CN211014553U - Boundary switch function detection circuit - Google Patents

Abstract

The utility model relates to a power grid equipment test instrument technical field, its aim at provide a boundary switch function detection circuitry, the utility model discloses a boundary switch function detection circuitry, including heavy current generator, P L C, fifth resistance, zero resistance, first resistance, zero contactor, first contactor, fifth contactor, sixth contactor, eighth contactor, tenth contactor and twelfth signal relay the utility model discloses the structure is fairly simple, low-priced, portable, the device of easy operation replaces expensive relay protection tester, does not need more frequent transform wiring, and the parameter of operating mode when can be more close joining in marriage net fault carries out more comprehensive detection to boundary switch protect function.

Description

A demarcation switch function detection circuit

technical field

The utility model relates to the technical field of power grid equipment testing instruments, in particular to a boundary switch function detection circuit.

Background technique

The demarcation switch is a device used for line protection of branch lines and end users. It has the function of automatic isolation of overhead line user faults and can automatically remove the ground fault in the user boundary. Among them, the demarcation switch with the circuit breaker as the main body can automatically remove the short-circuit fault between phases within the user boundary; the demarcation switch with the load switch as the main body can realize the isolation of the short-circuit fault between the phases in the user boundary by cooperating with the circuit breaker of the previous level. In order to avoid expanding the blackout range of the medium-voltage distribution network and affecting the normal power consumption of other users.

At present, most of the manufacturers have insufficient technical strength and small production scale. Most of them use their own production of switch bodies, and purchased controllers to form user boundary switches, which are prone to problems in function matching. In order to ensure the safety of the application of the demarcation switch, it is necessary to perform functional testing before it leaves the factory. In the prior art, when testing the function of the demarcation switch, the manufacturer generally uses a high-current generator for testing. This method is quite different from the line fault conditions encountered in the operation of the switch, and the detection is too one-sided. In engineering applications, when it is necessary to detect the protection function of the user boundary switch, the personnel of professional testing units generally use relay protection testers or high-current generators for testing. There are various testing methods, but there are basically different testing contents. It is comprehensive and prone to the problem that the test conditions differ greatly from the line fault conditions.

Utility model content

In order to solve the above problems existing in the prior art, the utility model provides a circuit for detecting the function of a boundary switch.

The technical scheme adopted by the utility model is:

A boundary switch function detection circuit, comprising a large current generator, a PLC, a fifth resistor, a zeroth resistor, a first resistor, a zeroth contactor, a first contactor, a fifth contactor, a sixth contactor, an eighth contactor contactor, tenth contactor and twelfth signal relay;

The power connection pole of the PLC is connected to both ends of the primary side winding of the high current generator; the zeroth signal output pole of the PLC is connected to the same name end of the primary side winding of the high current generator through the coil of the zeroth contactor, and the PLC The first signal output pole of the PLC is connected to the same name terminal of the primary side winding of the high current generator through the coil of the first contactor, and the fifth signal output pole of the PLC is connected to the primary side winding of the high current generator through the coil of the fifth contactor. The synonymous end of the PLC is connected, the sixth signal output pole of PLC is connected to the synonymous end of the primary side winding of the high current generator through the coil of the sixth contactor, and the eighth signal output pole of the PLC is connected to the coil of the eighth contactor with the The synonymous end of the primary side winding of the high-current generator is connected, the tenth signal output pole of the PLC is connected to the synonymous end of the primary side winding of the high-current generator through the coil of the tenth contactor, and the eighth signal input pole of the PLC is connected. Connect with the common negative pole of PLC through the contact of the twelfth signal relay;

Two ends of the primary side winding of the high current generator are respectively connected with two poles of the power supply; A detection point, the zeroth resistor and the contacts of the zeroth contactor are connected in series to form a first branch, the first resistor and the contacts of the first contactor are connected in series to form a second branch, and the first branch is connected to the first branch. Both branches are connected in parallel with the fifth resistor; the junction point of the fifth resistor and the contact of the fifth contactor is connected to the first detection point of phase B, the fifth resistor and the fifth contactor through the contact of the sixth contactor The junction point of the contact of the eighth contactor is connected to the first detection point of the C phase, and the junction point of the fifth resistor and the contact point of the fifth contactor is also connected to the live wire of the power supply; The different names of the secondary windings are respectively connected to the second detection point of A-phase, the second detection point of B-phase and the second detection point of C-phase through the contacts of the tenth contactor. The name end is connected with the junction point of the fifth resistor and the contact point of the fifth contactor through the coil of the twelfth signal relay, and the different end of the secondary winding of the high current generator is also connected with the neutral line of the power supply;

Both ends of the primary side winding of the large current generator are connected to the power supply pole of the demarcation switch.

Preferably, the boundary switch function detection circuit further includes a fourth resistor, a fourth contactor, a seventh contactor and a ninth contactor;

The fourth signal output pole of the PLC is connected to the synonymous end of the primary side winding of the high-current generator through the coil of the fourth contactor, and the seventh signal output pole of the PLC is connected to the primary side of the high-current generator through the coil of the seventh contactor. The synonymous end of the side winding is connected, and the ninth signal output pole of the PLC is connected to the synonymous end of the primary side winding of the large current generator through the coil of the ninth contactor;

The fourth resistor and the contacts of the fourth contactor are connected in series to form a third branch, and the third branch is connected in parallel with the fifth resistor; the opposite end of the secondary winding of the large current generator passes through the contact of the seventh contactor It is connected with the first detection point of the B phase, and the different end of the secondary winding of the large current generator is connected with the first detection point of the C phase through the contact point of the ninth contactor.

Further preferably, the boundary switch function detection circuit further includes a third resistor, a third contactor and an eleventh contactor;

The third signal output pole of the PLC is connected to the synonymous end of the primary side winding of the high current generator through the coil of the third contactor, and the eleventh signal output pole of the PLC is connected to the high current generator through the coil of the eleventh contactor The synonym end connection of the primary side winding;

The contacts of the third resistor and the third contactor are connected in series to form a fourth branch, and the fourth branch is connected in parallel with the fifth resistor;

One end of the contact point of the eleventh contactor is connected to the opposite end of the primary side winding of the large current generator, and the other end of the contact point of the eleventh contactor is connected to the power output pole of the demarcation switch.

Further preferably, the demarcation switch function detection circuit also includes a short circuit detection switch, an enlarged zero sequence current detection switch, a current calibration switch and a fault indicator detection switch; the second signal input pole of the PLC passes through the short circuit detection switch and the PLC common. The negative pole is connected, the third signal input pole of the PLC is connected to the common negative pole of the PLC by increasing the zero sequence current detection switch, the fourth signal input pole of the PLC is connected to the common negative pole of the PLC through the current calibration switch, and the fifth signal input pole of the PLC is connected to the common negative pole of the PLC. Connect with the common negative pole of PLC through the fault indicator detection switch.

Preferably, the boundary switch function detection circuit further includes a start switch and a stop switch; the zeroth signal input pole of the PLC is connected to the common negative pole of the PLC through the start switch, and the first signal input pole of the PLC is connected to the common negative pole of the PLC through the stop switch connect.

Preferably, the boundary switch function detection circuit further includes a leakage switch, a first air switch and a second air switch, the leakage switch is arranged between the primary side winding of the high current generator and the power supply, and the first air switch The second air switch is arranged between the primary side winding of the high current generator and the power connection pole of the PLC, and the second air switch is arranged between the primary side winding of the high current generator and the power supply connection pole of the demarcation switch.

Preferably, the power supply is a single-phase power frequency sine wave AC power supply.

Preferably, the detection method further includes a fault indicator detection method.

The beneficial effects of the present utility model are embodied in:

1. The device of the present utility model is relatively simple in structure, cheap, portable and easy to operate. It replaces the expensive relay protection tester, does not need to change the wiring more frequently, and can be relatively close to the parameters of the working conditions when the distribution network fails. The protection function is more comprehensively detected.

2. The utility model adopts automatic detection according to the flow through PLC, and it is not necessary to adjust various detection parameters during detection, and it is not necessary to change various wirings. The detection parameters and wiring methods are automatically converted by the device, so a functional switch detection process is normal. Time-consuming. The detection speed is more than 10 times faster than that of the detection devices such as the relay protection instrument and the high current generator in the prior art.

3. The detection of the boundary switch of the present invention increases whether the three-phase unbalanced load produces a zero-sequence overcurrent detection item, which is rarely considered in the detection of other methods in the past, and can effectively check out the combination of the synthetic zero-sequence current switch. Is the zero-order algorithm correct or not?

4. The utility model can be used to simply judge the quality of the fault indicator, so as to achieve the effect of one machine with multiple functions. It can solve the needs of grass-roots personnel engaged in power operation and maintenance and construction who need an instrument for fault finger detection, which is convenient for work.

Description of drawings

Fig. 1 is the circuit schematic diagram of embodiment 1;

Fig. 2 is the circuit schematic diagram of Embodiment 1 and the demarcation switch when performing switch function detection;

FIG. 3 is a circuit schematic diagram of Embodiment 1 and the demarcation switch when the fault indicator is detected.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted here that, although the description of these embodiments is used to help the understanding of the present invention, it does not constitute a limitation to the present invention. Specific structural and functional details disclosed herein are merely illustrative of example embodiments of the present invention. However, the present invention may be embodied in many alternative forms and should not be construed as limited to the embodiments set forth herein.

It should also be noted that in some alternative implementations, the functions/acts may occur out of the order in which they occur in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently, or the two figures shown in succession may sometimes be executed in the reverse order, depending upon the functionality/acts involved.

It should be understood that specific details are provided in the following description to facilitate a thorough understanding of example embodiments. However, it will be understood by those of ordinary skill in the art that example embodiments may be practiced without these specific details. For example, systems may be shown in block diagrams to avoid obscuring the examples with unnecessary detail. In other instances, well-known processes, structures and techniques may not be shown in unnecessary detail to avoid obscuring example embodiments.

Example 1:

This embodiment provides a boundary switch function detection circuit, as shown in FIG. 1 , including a large current generator T, a PLC, a fifth resistor R5, a zeroth resistor R0, a first resistor R1, a zeroth contactor C00, a first contactor C01, fifth contactor C05, sixth contactor C06, eighth contactor C08, tenth contactor C10 and twelfth signal relay C12;

In this embodiment, the PLC adopts a PLC manufactured by Xiamen Shuangyuan Technology Co., Ltd., which is a programmable controller with 8 inputs and 16 outputs, and the 16 outputs of the PLC are all realized by 5A relays. It should be understood that the PLC can also be a PLC with model FP-2020MR manufactured by Loudi Jiansi Control Co., Ltd. or MM-30MR-4MT-700-FX- manufactured by Shenzhen Zhongda Youkong Technology Co., Ltd. A PLC.

The rated capacity of the zeroth contactor C00, the first contactor C01, the second contactor C02, the third contactor C03, the tenth contactor C10 and the eleventh contactor C11 are all 25A; The rated capacity of the fifth contactor C05, the sixth contactor C06, the seventh contactor C07, the eighth contactor C08, and the ninth contactor C09 are all 2×63A; the working voltage of the twelfth signal relay C12 is AC 12V.

The power connection pole of the PLC is connected to both ends of the primary winding of the high current generator T; the VCC pin of the PLC is connected to the same name terminal of the primary winding of the high current generator T, and the GND pin of the PLC is connected to the high current generator The different-named terminal of the primary side winding of T is connected; the zeroth signal output pole of PLC is connected to the same-named terminal of the primary side winding of the high-current generator T through the coil of the zeroth contactor C00, and the first signal output pole of the PLC is connected through the The coil of a contactor C01 is connected to the same name terminal of the primary side winding of the high current generator T, and the fifth signal output pole of the PLC is connected to the same name terminal of the primary side winding of the high current generator T through the coil of the fifth contactor C05 Connection, the sixth signal output pole of PLC is connected to the different end of the primary side winding of the large current generator T through the coil of the sixth contactor C06, and the eighth signal output pole of the PLC is connected to the large current through the coil of the eighth contactor C08. The synonymous end of the primary winding of the current generator T is connected, the tenth signal output pole of the PLC is connected to the synonymous end of the primary winding of the high current generator T through the coil of the tenth contactor C10, and the eighth signal of the PLC The input pole is connected to the common negative pole of the PLC through the contact of the twelfth signal relay C12;

The two ends of the primary side winding of the high current generator T are respectively connected with the two poles of the power supply; The same-named end of the power supply is connected to the neutral line of the power supply; the same-named end of the secondary winding of the high-current generator T is connected to the first detection point A1 of the A-phase through the fifth resistor R5 and the contacts of the fifth contactor C05 in turn. The zeroth resistor R0 and the contacts of the zeroth contactor C00 are connected in series to form a first branch, the first resistor R1 and the contacts of the first contactor C01 are connected in series to form a second branch, and the first branch and the second branch are connected in series. The branches are all connected in parallel with the fifth resistor R5; the junction point of the fifth resistor R5 and the contact point of the fifth contactor C05 is connected to the first detection point B1 of the B phase through the contact point of the sixth contactor C06, and the fifth resistor R5 The junction point with the contact point of the fifth contactor C05 is connected to the C-phase first detection point C1 through the contact point of the eighth contactor C08, and the junction point of the fifth resistor R5 and the contact point of the fifth contactor C05 is also connected to the power supply. The live wire connection of the high-current generator T; Detection point C2, the synonymous end of the secondary winding of the high current generator T is connected to the junction point of the fifth resistor R5 and the contact point of the fifth contactor C05 through the coil of the twelfth signal relay C12, the high current generator The synonym end of the secondary winding of T is also connected to the neutral line of the power supply;

Both ends of the primary side winding of the high current generator T are connected with the power supply pole of the demarcation switch; The synonymous end of the primary winding of T is connected with the power output pole of the demarcation switch; specifically, as shown in Figure 2, the demarcation switch includes a demarcation switch controller and a switch body, wherein the demarcation switch controller includes a control output circuit, an AC sampling Circuit and CPU, the switch body is connected with the first detection point A1 of phase A, the first detection point B1 of phase B, the first detection point C1 of phase C, the second detection point A2 of phase A, the second detection point B2 of phase B and the first detection point of phase C The two detection points C2 are electrically connected, and the synonymous end of the primary winding of the high-current generator T is electrically connected to the demarcation switch controller. The switch body can send the sampling signal to the CPU through the AC sampling circuit, and the CPU processes the sampling signal and sends it to the CPU. The processed sampling signal is sent to the control output circuit, and the control output circuit can feed back the processed sampling signal to the switch body.

The A-phase first detection point A1 and the A-phase second detection point A2 are respectively connected to both ends of the A-phase switch of the boundary switch, and the B-phase first detection point B1 and the B-phase second detection point B2 are respectively connected to the B-phase switch of the boundary switch. Both ends of the switch are connected, and the C-phase first detection point C1 and the C-phase second detection point C2 are respectively connected to both ends of the C-phase switch of the demarcation switch.

The boundary switch function detection circuit also includes a second resistor R2 and a second contactor C02. The second signal output pole of the PLC is connected to the different end of the primary side winding of the high-current generator T through the coil of the second contactor C02. The two resistors R2 and the contacts of the second contactor C02 are connected in series to form a fifth branch, and the fifth branch is connected in parallel with the fifth resistor R5.

Further, the boundary switch function detection circuit further includes a fourth resistor R4, a fourth contactor C04, a seventh contactor C07 and a ninth contactor C09;

The fourth signal output pole of the PLC is connected to the opposite end of the primary winding of the high current generator T through the coil of the fourth contactor C04, and the seventh signal output pole of the PLC is connected to the high current through the coil of the seventh contactor C07 The synonymous end of the primary side winding of the generator T is connected, and the ninth signal output pole of the PLC is connected to the synonymous end of the primary side winding of the high-current generator T through the coil of the ninth contactor C09;

The contacts of the fourth resistor R4 and the fourth contactor C04 are connected in series to form a third branch, and the third branch is connected in parallel with the fifth resistor R5; The contact of the contactor C07 is connected to the first detection point B1 of the B phase, and the opposite end of the secondary winding of the large current generator T is connected to the first detection point C1 of the C phase through the contact of the ninth contactor C09.

Further, the boundary switch function detection circuit further includes a third resistor R3, a third contactor C03 and an eleventh contactor C11;

The third signal output pole of the PLC is connected to the opposite end of the primary side winding of the large current generator T through the coil of the third contactor C03, and the eleventh signal output pole of the PLC is connected to the large current through the coil of the eleventh contactor C11. The connection of the different ends of the primary side winding of the current generator T;

The contacts of the third resistor R3 and the third contactor C03 are connected in series to form a fourth branch, and the fourth branch is connected in parallel with the fifth resistor R5;

One end of the contact point of the eleventh contactor C11 is connected to the opposite end of the primary winding of the large current generator T, and the other end of the contact point of the eleventh contactor C11 is connected to the power output pole of the boundary switch.

The contact of the zeroth contactor C00, the contact of the first contactor C01, the contact of the second contactor C02, the contact of the third contactor C03, the contact of the fifth contactor C05, the contact of the sixth contactor C06 contacts of the eighth contactor C08, contacts of the tenth contactor C10, contacts of the fourth contactor C04, contacts of the seventh contactor C07, contacts of the ninth contactor C09, The contacts of the eleventh contactor C11 and the contacts of the twelfth signal relay C12 are both normally open contacts.

In this embodiment, the boundary switch function detection circuit further includes a short-circuit detection switch, an enlarged zero-sequence current detection switch, a current calibration switch and a fault indicator detection switch; the second signal input pole of the PLC passes through the short-circuit detection switch and the PLC's The common negative pole is connected, the third signal input pole of the PLC is connected to the common negative pole of the PLC by increasing the zero-sequence current detection switch, the fourth signal input pole of the PLC is connected to the common negative pole of the PLC through the current calibration switch, and the fifth signal input pole of the PLC is connected to the common negative pole of the PLC. The pole is connected to the common negative pole of the PLC through the fault indicator detection switch.

In this embodiment, the boundary switch function detection circuit further includes a start switch and a stop switch; the zeroth signal input pole of the PLC is connected to the common negative pole of the PLC through the start switch, and the first signal input pole of the PLC is connected to the PLC through the stop switch. Common negative connection.

In this embodiment, the boundary switch function detection circuit further includes a leakage switch Z1, a first air switch Z2 and a second air switch Z3, and the leakage switch Z1 is arranged between the primary side winding of the high current generator T and the power supply The first air switch Z2 is arranged between the primary side winding of the high current generator T and the power connection pole of the PLC, and the second air switch Z3 is arranged between the primary side winding of the high current generator T and the boundary switch between the power connections.

In this embodiment, the power supply is a single-phase power frequency sine wave AC power supply. Specifically, in this embodiment, a single-phase power supply is used for power supply and detection, and a three-phase power supply is not used, and the power is not large, which is convenient for power connection. Moreover, the structure is simple, the weight is relatively light, and the manufacturing cost is low, which is also conducive to detection under field conditions.

The beneficial effects of this embodiment are as follows:

1. The structure of this embodiment is relatively simple, cheap, portable and easy to operate. It replaces the expensive relay protection tester, does not need to change the wiring more frequently, and can be relatively close to the parameters of the working conditions when the distribution network fails. The protection function is more comprehensively detected.

2. In this embodiment, automatic detection according to the process is adopted by PLC, and there is no need to adjust various detection parameters during the detection, and it is not necessary to change various wirings. The detection parameters and wiring methods are automatically converted by the device, so a functional switch detection process is normal. Time-consuming. The detection speed is more than 10 times faster than that of the detection devices such as the relay protection instrument and the high current generator in the prior art.

3. The detection of the boundary switch in this embodiment adds a detection item of whether the three-phase unbalanced load produces zero-sequence overcurrent, which is rarely considered in other detection methods in the past. Is the zero-order algorithm correct or not?

4. This embodiment can be used to simply judge whether the fault indicator is good or bad, so as to achieve the effect of one machine with multiple uses. It can solve the needs of grass-roots personnel engaged in power operation and maintenance and construction who need an instrument for fault finger detection, which is convenient for work.

Example 2:

This embodiment provides a detection method according to the demarcation switch function detection circuit in Embodiment 1, which includes a switch function detection method. The connection diagram of the demarcation switch and the switch function detection in Embodiment 1 is shown in FIG. 2 . The detection method includes the following steps:

Perform ground fault zero-sequence overcurrent setting lower limit detection;

Perform ground fault zero-sequence overcurrent setting upper limit detection;

Perform zero-sequence overcurrent detection for three-phase unbalanced load (two-phase flow, simulating phase-opening condition) and lower limit detection of phase-to-phase short-circuit overcurrent flow rate;

Check whether the three-phase unbalanced load has zero-sequence overcurrent detection (one big and two small, three-phase current, simulating the three-phase power unbalanced condition);

Carry out the upper limit detection of the over-current flow rate determination value in the interphase short circuit (including no power on the power supply side at the moment of short circuit, simulating the tripping condition of the substation switch after the fault).

Further, the detection method also includes a fault indicator detection method. A schematic diagram of the connection between the boundary switch and the fault indicator detection in Embodiment 1 is shown in FIG. 2 .

Specifically, before the detection is performed, the first detection point A1 of the A phase and the second detection point A2 of the A phase are respectively connected to both ends of the A phase switch of the boundary switch, and the first detection point B1 of the B phase and the second detection point of the B phase are respectively connected. The detection point B2 is respectively connected with both ends of the B-phase switch of the boundary switch, and the C-phase first detection point C1 and the C-phase second detection point C2 are respectively connected with both ends of the C-phase switch of the boundary switch;

The method for detecting the lower limit of the ground fault zero-sequence overcurrent setting value includes the following steps, taking the A-phase detection of the boundary switch as an example:

The PLC sends electrical signals to the coil of the fifth contactor C05 and the coil of the tenth contactor C10 respectively, and the contacts of the fifth contactor C05 and the tenth contactor C10 are closed; The same-named end of the primary side winding of the generator T, the same-named end of the secondary side winding of the high-current generator T, the contacts of the fifth resistor R5 and the fifth contactor C05 are sent to one end of the A-phase switch of the demarcation switch, and the power The zero-line voltage is sent to the A phase of the demarcation switch through the synonym end of the primary side winding of the high current generator T, the synonym end of the secondary side winding of the high current generator T and the contact of the tenth contactor C10. the other end of the switch;

The PLC reads the opening and closing signals of the contacts of the twelfth signal relay C12. Preferably, the PLC reads the opening and closing signals of the contacts of the twelfth signal relay C12 after 0.5 seconds, and sets a delay of 0.5 seconds to prevent each Influence of switch jitter; if the demarcation switch is in the open state, the contact of the twelfth signal relay C12 is closed, and the PLC can read the closing signal of the contact of the twelfth signal relay C12; if the demarcation switch is in the closed state, the The contact of the twelfth signal relay C12 is disconnected, and the PLC can read the open signal of the contact of the twelfth signal relay C12; if the PLC reads the closing signal of the contact of the twelfth signal relay C12, this When the demarcation switch is closed, the contact of the twelfth signal relay C12 is disconnected, the PLC reads the disconnection signal of the contact of the twelfth signal relay C12, and the PLC makes the detection program wait for 10 seconds before entering the next step. Otherwise the PLC directly goes to the next step. It should be noted that the PLC makes the detection program wait for 10 seconds before entering the next step, to wait for the demarcation switch with automatic electric energy storage to complete the energy storage, or the panel to the opening energy storage position after the manual operation mechanism is closed;

The PLC sends an electrical signal to the coil of the zeroth contactor C00, and the contact of the zeroth contactor C00 is closed;

The PLC reads the opening and closing signals of the contacts of the twelfth signal relay C12. Preferably, the PLC waits for 4 seconds before reading the opening and closing signals of the contacts of the twelfth signal relay C12, and then stops sending the signal to the zeroth contactor C00. The coil sends an electrical signal, and the contact of the zeroth contactor C00 is disconnected; if the PLC reads the disconnection signal of the contact of the twelfth signal relay C12, it determines that the ground fault of the A-phase switch of the demarcation switch is over zero sequence. The current setting lower limit function is normal; if the PLC reads the closing signal of the contact of the twelfth signal relay C12, it is determined that the ground fault zero-sequence overcurrent setting lower limit function of the A-phase switch of the boundary switch is abnormal;

The ground fault zero-sequence overcurrent fixed value upper limit detection includes the following steps, taking the A-phase detection of the boundary switch as an example:

The PLC sends electrical signals to the coil of the fifth contactor C05 and the coil of the tenth contactor C10 respectively, and the contacts of the fifth contactor C05 and the tenth contactor C10 are closed; The same-named end of the primary side winding of the generator T, the same-named end of the secondary side winding of the high-current generator T, the contacts of the fifth resistor R5 and the fifth contactor C05 are sent to one end of the A-phase switch of the demarcation switch, and the power The zero-line voltage is sent to the A phase of the demarcation switch through the synonym end of the primary side winding of the high current generator T, the synonym end of the secondary side winding of the high current generator T and the contact of the tenth contactor C10. the other end of the switch;

The PLC reads the opening and closing signals of the contacts of the twelfth signal relay C12. Preferably, the PLC reads the opening and closing signals of the contacts of the twelfth signal relay C12 after 0.5 seconds, and sets a delay of 0.5 seconds to prevent each Influence of switch jitter; if the demarcation switch is in the open state, the contact of the twelfth signal relay C12 is closed, and the PLC can read the closing signal of the contact of the twelfth signal relay C12; if the demarcation switch is in the closed state, the The contact of the twelfth signal relay C12 is disconnected, and the PLC can read the open signal of the contact of the twelfth signal relay C12; if the PLC reads the closing signal of the contact of the twelfth signal relay C12, this When the demarcation switch is closed, the contact of the twelfth signal relay C12 is disconnected, the PLC reads the disconnection signal of the contact of the twelfth signal relay C12, and the PLC makes the detection program wait for 10 seconds before entering the next step. Otherwise the PLC directly goes to the next step. It should be noted that the PLC makes the detection program wait for 10 seconds before entering the next step, to wait for the demarcation switch with automatic electric energy storage to complete the energy storage, or the panel to the opening energy storage position after the manual operation mechanism is closed;

The PLC sends electrical signals to the coil of the zeroth contactor C00 and the coil of the first contactor C01, and the contacts of the zeroth contactor C00 and the first contactor C01 are both closed;

The PLC reads the opening and closing signals of the contacts of the twelfth signal relay C12. Preferably, the PLC waits for 4 seconds before reading the opening and closing signals of the contacts of the twelfth signal relay C12, and then stops sending the signal to the zeroth contactor C00. The coil of the first contactor C01 and the coil of the first contactor C01 send electrical signals, and the contact of the zeroth contactor C00 and the contact of the first contactor C01 are both disconnected; if the PLC reads the contact of the twelfth signal relay C12 If the signal is closed, it is determined that the ground fault zero-sequence overcurrent setting upper limit of the A-phase switch of the demarcation switch is normal; if the PLC reads the disconnection signal of the contact of the twelfth signal relay C12, it is determined that the A-phase of the demarcation switch The ground fault zero-sequence overcurrent setting upper limit function of the switch is abnormal.

The detection principles of the B-phase of the boundary switch and the C-phase of the boundary switch are the same as above.

This detection step is to verify whether the demarcation switch can be opened according to the instruction of the controller when the zero-sequence current is higher than the fixed value.

The method for detecting whether the three-phase unbalanced load produces zero-sequence overcurrent and the method for detecting the lower limit of the interphase short-circuit overcurrent flow rate determination value include the following steps. A-B phase detection as an example:

The PLC sends electrical signals to the coil of the fifth contactor C05 and the coil of the seventh contactor C07 respectively, the contacts of the fifth contactor C05 and the contact of the seventh contactor C07 are closed, and the PLC reads the first contact after 0.5 seconds. For the opening and closing signals of the contacts of the twelve-signal relay C12, a delay of 0.5 seconds is set to prevent the influence of each switch jitter; The same-named end of the secondary side winding, the contact of the fifth resistor R5 and the fifth contactor C05 are sent to one end of the A-phase switch of the demarcation switch, and the zero line voltage of the power supply passes through the primary side winding of the high current generator T in turn. The different end, the different end of the secondary winding of the high current generator T and the contact of the seventh contactor C07 are sent to one end of the B-phase switch of the demarcation switch. If the contact of the boundary switch is in the open state, the contact of the twelfth signal relay C12 is closed, the PLC reads the contact closure signal of the twelfth signal relay C12, and the boundary switch is closed at this time, and the twelfth signal relay C12 The contact is disconnected, the PLC reads the disconnection signal of the contact of the twelfth signal relay C12, the PLC makes the detection program wait for 10 seconds, and then goes to the next step.

The PLC sends an electrical signal to the coil of the fourth contactor C04, and the contact of the fourth contactor C04 is closed;

PLC waits for 1 second;

The PLC reads the opening and closing signal of the contact of the twelfth signal relay C12; if the PLC reads the disconnection signal of the contact of the twelfth signal relay C12, it determines that the A-B phase-to-phase short circuit of the demarcation switch and the lower limit detection function of the flow rate break are normal. . If the closing signal of the contact of the twelfth signal relay C12 is read, it is determined that the A-B phase-to-phase short circuit of the boundary switch is abnormal, and the lower limit detection function of the overcurrent is abnormal, and the PLC records the abnormality of the function.

The PLC waits for another 3 seconds, and then reads the opening and closing signal of the contact of the twelfth signal relay C12. If the disconnection signal of the contact point of the twelfth signal relay C12 is read, it is determined that the three-phase unbalanced load of the boundary switch does not produce zero-sequence overcurrent tripping. If it reads the closing signal of the twelfth signal relay C12, it is determined that the three-phase unbalanced load of the boundary switch produces a zero-sequence overcurrent trip, and the PLC records the abnormality of this function.

The detection principles of B-C phase of the boundary switch and C-A phase of the boundary switch are the same as above.

This detection step is to verify the demarcation switch. When the three-phase unbalanced load has zero-sequence overcurrent trip, the three-phase unbalanced load simulates the open-phase condition, the two-phase current flows, and the three-phase current vector sum is 0. And when the line current is lower than the phase-to-phase short-circuit overcurrent value, the opening should not be performed.

The method for detecting whether the three-phase unbalanced load produces zero-sequence overcurrent is that one large and two small, three-phase current flow, and simulate the unbalanced three-phase power consumption condition, including the following steps, taking the A-BC phase detection of the boundary switch as example:

The PLC sends electrical signals to the coil of the fifth contactor C05, the coil of the seventh contactor C07 and the coil of the ninth contactor C09, respectively, the contacts of the fifth contactor C05, the contacts of the seventh contactor C07 and the ninth contactor C09 The contact of the contactor C09 is closed, and the PLC reads the opening and closing signal of the contact of the twelfth signal relay C12 after 0.5 seconds; The same-named end of the secondary winding of the generator T, the contacts of the fifth resistor R5 and the fifth contactor C05 are sent to one end of the A-phase switch of the demarcation switch, and the zero line voltage of the power supply passes through the high current generator T in turn. The synonym end of the primary side winding, the synonym end of the secondary side winding of the high current generator T and the contact of the seventh contactor C07 are sent to one end of the B-phase switch of the demarcation switch, and the other way of the neutral voltage of the power supply It is sent to one end of the B-phase switch of the boundary switch through the synonym end of the primary winding of the high current generator T, the synonym end of the secondary winding of the high current generator T and the contact of the ninth contactor C09. If the demarcation switch is in the off state, the contact of the twelfth signal relay C12 is closed, and the PLC reads the closing signal of the contact of the twelfth signal relay C12. At this time, the demarcation switch is closed, and the contact of the twelfth signal relay C12 is closed. When disconnected, PLC reads the disconnection signal of the contact of the twelfth signal relay C12, and the PLC makes the detection program wait for 10 seconds to enter the next step. Otherwise the PLC directly goes to the next step.

The PLC command C04 closes, the PLC waits for 4 seconds, and reads the opening and closing signal of the twelfth signal relay C12. Then C04 is disconnected.

If the twelfth signal relay C12 disconnection signal is read, it is considered that the three-phase unbalanced load of the boundary switch does not cause zero sequence overcurrent tripping, and the detection continues to the next step. If the closing signal of the twelfth signal relay C12 is read, it is considered that the three-phase unbalanced load of the boundary switch produces a zero-sequence overcurrent trip, and the PLC records the abnormality of this function and continues to the next step to detect.

The detection principle of the B-CA phase of the boundary switch and the C-AB phase of the boundary switch is the same as above.

The detection step is to verify the boundary switch, when the three-phase unbalanced load produces zero-sequence overcurrent trip, but the three-phase current vector sum is 0.

This item is added to prevent some manufacturers from cheating in the detection of zero-sequence overcurrent tripping for three-phase unbalanced loads. Two-phase flow is used, that is, the three-phase unbalanced load that simulates the lack of phase conditions has a zero-sequence overcurrent detection method. Some manufacturers have set up a cheating method of blocking zero-sequence overcurrent tripping when one-phase current is 0 in the control program. After adopting three-phase current flow, for example, in A-BC detection, due to the difference in contact resistance in the primary side connection of B and C phases, the current passing through A phase is not evenly distributed to B and C phases, but a random number. , which can effectively prevent the above cheating methods.

The method for detecting the upper limit of the over-current flow rate determination value in the interphase short circuit, that is, the power supply side has no power at the moment of the short circuit, and simulates the tripping condition of the substation switch after the fault, including the following steps, taking the A-B phase detection of the boundary switch as an example:

The PLC commands C05 and C07 to close, and the PLC reads the opening and closing signal of the twelfth signal relay C12 after 0.5 seconds; the live line voltage is sent from L2→R5→L3→C05 to the A1 side of the demarcation switch, and the neutral line voltage is sent from N2→N3→C07 to the side of the boundary switch Demarcation switch B1 side. If the contact of the demarcation switch is in the open state, the voltage relay of the twelfth signal relay C12 is closed with a voltage, and the PLC reads the closing signal of the twelfth signal relay C12, and the PLC waits for the detection procedure and does not execute the next step; Demarcation switch, the contact of the twelfth signal relay C12 is disconnected, the PLC reads the disconnection signal of the twelfth signal relay C12, the PLC makes the detection program wait for 10 seconds, and then goes to the next step. If the PLC closes C05 and C07, and the PLC reads the opening signal of the twelfth signal relay C12 after 0.5 seconds, it will not wait for the program to proceed.

The PLC commands C03 and C04 to close, the PLC waits for 1 second, and reads the opening and closing signal of the twelfth signal relay C12. Then C03 and C04 are disconnected.

If the closing signal of the twelfth signal relay C12 is read, it is considered that the demarcation switch has a normal interphase short-circuit and over-flow rate breaking upper limit detection function, and the detection continues to the next step. If the twelfth signal relay C12 disconnection signal is read, it is considered that the boundary switch interphase short-circuit and over-current flow cut-off upper limit detection function is abnormal, and the PLC records this function abnormality and continues to the next step for detection.

The B-C phase detection principle of the boundary switch is the same as above.

This detection step is to verify the demarcation switch. When the phase-to-phase short-circuit current is higher than the fixed value, it should act to open the switch. At this time, the outgoing switch of the substation is not opened, and the distribution line still has voltage.

In the detection of the C-A phase of the boundary switch, the PLC commands C05 and C09 to close, and the PLC reads the opening and closing signal of the twelfth signal relay C12 after 0.5 seconds; the live wire voltage is sent from L2→R5→L3→C05 to the boundary switch A1 side, the neutral line The voltage is sent to the C1 side of the demarcation switch from N2→N3→C09. If the contact of the demarcation switch is in the open state, the voltage relay of the twelfth signal relay C12 is closed with a voltage, and the PLC reads the closing signal of the twelfth signal relay C12, and the PLC waits for the detection procedure and does not execute the next step; Demarcation switch, the contact of the twelfth signal relay C12 is disconnected, the PLC reads the disconnection signal of the twelfth signal relay C12, the PLC makes the detection program wait for 10 seconds, and then goes to the next step. If the PLC closes C05 and C09, and the PLC reads the opening signal of the twelfth signal relay C12 after 0.5 seconds, it will not wait for the program to proceed.

The PLC commands C03, C04, and C11 to close, the PLC waits for 1 second, and reads the opening and closing signal of the twelfth signal relay C12.

If the closing signal of the twelfth signal relay C12 is read, it is considered that the demarcation switch has a normal interphase short-circuit and over-flow rate breaking upper limit detection function, and the detection continues to the next step. If the twelfth signal relay C12 disconnection signal is read, it is considered that the interphase short circuit of the boundary switch and the upper limit detection function of the flow rate and the upper limit are abnormal, and the PLC records the abnormality of this function. After C11 is closed, after a delay of 1 second, C11 is disconnected. The whole inspection is completed.

This detection step is to verify the demarcation switch. When the phase-to-phase short-circuit current is higher than the fixed value, it should act to open the switch. At this time, the outgoing switch of the substation is opened, and the distribution line has no voltage.

A schematic diagram of the connection between the boundary switch and the fault indicator detection in Embodiment 1 is shown in Figure 3, and the fault indicator detection method includes the following steps:

Pass 360A current 0.5S;

Manually observe whether the card is flopped;

Pass 7A current for 1min;

Turn on the 360A current again for 0.5S;

Manual observation to see if the card is flopped.

In the prior art, for the fault indicator, because it is not very important in the distribution network, the price is also low (ordinary type 100 yuan / piece), and the special detection device is expensive (more than 100,000 yuan), and the general municipal level. The following power supply companies, construction teams, and professional testing companies are difficult to have testing equipment, so it is difficult to understand the status of the fault indicator after new installation or operation for a period of time. However, this embodiment can generate a controllable large current, so it can also be used for simple judgment on the quality of the fault indicator by the way, so as to achieve the effect of one machine with multiple uses.

The multiple embodiments described above are only illustrative. If the units described as separate components are involved, they may or may not be physically separated; if the components shown as units are involved, they may or may not be physically separated. It may not be a physical unit, that is, it may be located in one place, or it may be distributed over multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.

The above embodiments are only used to illustrate the technical solutions of the present utility model, but not to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be used for the foregoing implementations. Modifications are made to the technical solutions described in the examples, or equivalent replacements are made to some of the technical features. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Finally, it should be noted that the present invention is not limited to the above-mentioned optional embodiments, and anyone can draw other various forms of products under the inspiration of the present invention. The above specific embodiments should not be construed as limiting the protection scope of the present invention, which should be defined in the claims, and the description can be used to interpret the claims.

Claims (7)

1. The demarcation switch function detection circuit is characterized by comprising a large current generator (T), a P L C, a fifth resistor (R5), a zero resistor (R0), a first resistor (R1), a zero contactor (C00), a first contactor (C01), a fifth contactor (C05), a sixth contactor (C06), an eighth contactor (C08), a tenth contactor (C10) and a twelfth signal relay (C12);

a power supply connection pole of the P L C is connected with two ends of a primary winding of the large current generator (T), a zeroth signal output pole of the P L C is connected with a dotted terminal of the primary winding of the large current generator (T) through a coil of a zeroth contactor (C00), a first signal output pole of the P L C is connected with a dotted terminal of the primary winding of the large current generator (T) through a coil of a first contactor (C01), a fifth signal output pole of the P L C is connected with a dotted terminal of the primary winding of the large current generator (T) through a coil of a fifth contactor (C05), a sixth signal output pole of the P L C is connected with the dotted terminal of the primary winding of the large current generator (T) through a coil of a sixth contactor (C06), an eighth signal output pole of the P L C is connected with the dotted terminal of the primary winding of the large current generator (T) through a coil of an eighth contactor (C08), a tenth signal output pole of the P L C is connected with a dotted terminal of a twelfth signal input terminal of a twelfth contactor (C L);

two ends of a primary side winding of the large-current generator (T) are respectively connected with two poles of a power supply; the dotted terminal of a secondary side winding of a large-current generator (T) is connected with an A-phase first detection point (A1) through contacts of a fifth resistor (R5) and a fifth contactor (C05) in sequence, the contacts of a zero resistor (R0) and a zero contactor (C00) are connected in series to form a first branch, the contacts of a first resistor (R1) and a first contactor (C01) are connected in series to form a second branch, and the first branch and the second branch are connected with the fifth resistor (R5) in parallel; a connection point of contacts of a fifth resistor (R5) and a fifth contactor (C05) is connected with a B-phase first detection point (B1) through a contact of a sixth contactor (C06), a connection point of contacts of the fifth resistor (R5) and a fifth contactor (C05) is connected with a C-phase first detection point (C1) through a contact of an eighth contactor (C08), and a connection point of contacts of the fifth resistor (R5) and a fifth contactor (C05) is also connected with a live wire of a power supply; the synonym end of the secondary side winding of the large-current generator (T) is respectively connected with an A-phase second detection point (A2), a B-phase second detection point (B2) and a C-phase second detection point (C2) through a contact of a tenth contactor (C10), the synonym end of the secondary side winding of the large-current generator (T) is connected with a combination point of contacts of a fifth resistor (R5) and a fifth contactor (C05) through a coil of a twelfth signal relay (C12), and the synonym end of the secondary side winding of the large-current generator (T) is also connected with a zero line of a power supply;

and two ends of a primary side winding of the large-current generator (T) are connected with a power supply electrode of the boundary switch.

2. The demarcation switch function detection circuit of claim 1, wherein: the demarcation switch function detection circuit further comprises a fourth resistor (R4), a fourth contactor (C04), a seventh contactor (C07) and a ninth contactor (C09);

a fourth signal output electrode of the P L C is connected to the synonym terminal of the primary winding of the large current generator (T) through a coil of a fourth contactor (C04), a seventh signal output electrode of the P L C is connected to the synonym terminal of the primary winding of the large current generator (T) through a coil of a seventh contactor (C07), and a ninth signal output electrode of the P L C is connected to the synonym terminal of the primary winding of the large current generator (T) through a coil of a ninth contactor (C09);

a fourth resistor (R4) and a contact of a fourth contactor (C04) are connected in series to form a third branch, and the third branch is connected with a fifth resistor (R5) in parallel; the synonym end of the secondary side winding of the large-current generator (T) is connected with the first detection point (B1) of the B phase through the contact of a seventh contactor (C07), and the synonym end of the secondary side winding of the large-current generator (T) is connected with the first detection point (C1) of the C phase through the contact of a ninth contactor (C09).

3. The demarcation switch function detection circuit of claim 2, wherein: the demarcation switch function detection circuit also comprises a third resistor (R3), a third contactor (C03) and an eleventh contactor (C11);

a third signal output electrode of the P L C is connected to the synonym terminal of the primary winding of the large current generator (T) through a coil of a third contactor (C03), and an eleventh signal output electrode of the P L C is connected to the synonym terminal of the primary winding of the large current generator (T) through a coil of an eleventh contactor (C11);

the third resistor (R3) and a contact of the third contactor (C03) are connected in series to form a fourth branch, and the fourth branch is connected with the fifth resistor (R5) in parallel;

one end of a contact of the eleventh contactor (C11) is connected to the unlike end of the primary winding of the large current generator (T), and the other end of the contact of the eleventh contactor (C11) is connected to the power output electrode of the boundary switch.

4. The boundary switch function detection circuit of claim 3, further comprising a short-circuit detection switch, an increasing zero-sequence current detection switch, a current correction switch and a fault indicator detection switch, wherein the second signal input pole of P L C is connected to the common negative pole of P L C through the short-circuit detection switch, the third signal input pole of P L C is connected to the common negative pole of P L C through the increasing zero-sequence current detection switch, the fourth signal input pole of P L C is connected to the common negative pole of P L C through the current correction switch, and the fifth signal input pole of P L C is connected to the common negative pole of P L C through the fault indicator detection switch.

5. The demarcation switch function detection circuit of claim 1, further comprising a start switch and a stop switch, wherein the zeroth signal input pole of P L C is connected to the common negative pole of P L C through the start switch, and the first signal input pole of P L C is connected to the common negative pole of P L C through the stop switch.

6. The boundary switch function detection circuit of claim 1, further comprising a leakage switch (Z1), a first air switch (Z2) and a second air switch (Z3), wherein the leakage switch (Z1) is disposed between the primary winding of the large current generator (T) and the power supply, the first air switch (Z2) is disposed between the primary winding of the large current generator (T) and the power supply connection terminal of P L C, and the second air switch (Z3) is disposed between the primary winding of the large current generator (T) and the power supply connection terminal of the boundary switch.

7. The demarcation switch function detection circuit of claim 1, wherein: the power supply is a single-phase power frequency sine wave alternating current power supply.

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