CN104242256B - The regioselectivity chained approach of breaker, device and system - Google Patents

Abstract

The embodiment of the invention discloses an area selective interlocking method, device and system of circuit breakers. The method includes: setting a fault current threshold value; when the non-last stage circuit breaker determines that the detected fault current value is not less than the fault current threshold value, calculating the regional selective chain time t _zsi and/or based on the detected fault current value or the backup protection time t _sd , where the regional selectivity interlocking time t _zsi decreases as the detected fault current value increases, and the backup protection time t _sd decreases as the detected fault current value increases; it is judged that the non-final circuit breaker is in Whether the regional selective interlocking input signal from the next-stage circuit breaker is received within the regional selective interlocking time t _zsi , if yes, if the fault still exists after the standby protection time t _sd arrives, the non-final stage circuit breaker will trip; If not, the non-last stage circuit breaker trips after the zone selectivity interlocking time t _{zsi is} reached. Embodiments of the present invention reduce adverse effects of thermal and electromagnetic effects on lines, cables and circuit breakers in the system.

Description

Area-selective interlocking method, apparatus and system for circuit breakers

technical field

The invention relates to the field of power distribution technology, in particular to the field of circuit breakers.

Background technique

Selective protection is a basic requirement for relay protection of power supply and distribution systems. The specific meaning of selective protection means that when the system fails, the faulty part can be cut off from the system within the minimum range, so as to ensure the continuous power supply of the non-faulty part to the greatest extent. The use of Zone-Selective Interlocking (ZSI, Zone-Selective Interlocking) technology can better solve the problem of selective cooperation between low-voltage network levels. ZSI refers to a practical technology to realize the selectivity of the protection area. Its function is to realize the protection and remove the fault in the area in the shortest time under the premise of ensuring the selective cooperation between the upper and lower levels. That is, when a fault occurs in the lower protection area, The fault is quickly removed by the lower-level protection, and the upper-level protection is blocked at the same time, so as to realize the selective cooperation between the levels. In the traditional ZSI technology, if the current protection is disabled, when the upper-level circuit breaker detects a fault, it delays the zone selectivity interlocking time (t _zsi ) to wait for the ZSI signal from the lower-level circuit breaker. When the upper-level circuit breaker receives the ZSI signal, the upper-level circuit breaker delays the backup protection time (t _sd ) (that is, the upper-level circuit breaker does not perform the tripping action within the t _sd time), if the fault still exists after the t _sd time, the upper-level circuit breaker tripping to realize the function of backup protection. When the upper level circuit breaker does not receive the ZSI signal, the upper level circuit breaker trips after t _zsi time. In this technique, both t _zsi and t _sd are fixed time values. In the case of a large fault current (for example, tens of times the rated current), the thermal effect and electromagnetic effect within the time of t _zsi and t _sd will have a great adverse effect on the lines/cables in the system, and the service life of the circuit breaker will inevitably be affected.

Contents of the invention

The embodiment of the present invention proposes an area-selective interlocking method of circuit breakers to reduce adverse effects of fault currents.

Embodiments of the present invention provide a circuit breaker to reduce adverse effects of fault current.

Embodiments of the present invention propose a circuit breaker system to reduce adverse effects of fault currents.

The technical scheme of the embodiment of the present invention is as follows:

A region-selective interlocking method for circuit breakers, comprising:

Set the fault current threshold value;

When the non-last stage circuit breaker determines that the detected fault current value is not less than the fault current threshold value, it calculates the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd based on the detected fault current value, where the zone selection The interlocking time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value;

Judging whether the non-last stage circuit breaker receives the regional selective interlocking input signal from the next stage circuit breaker within the region selective interlocking time t _zsi , if yes, when the backup protection time t _sd arrives, if the failure If it still exists, the non-last stage circuit breaker trips; if not, the non-final stage circuit breaker trips after the zone selective interlocking time t _{zsi is} reached.

The calculation of zone selectivity interlocking time t _zsi and/or backup protection time t _sd based on the detected fault current value includes:

Calculating zone selective interlocking time t _zsi and/or backup protection time t _sd directly using fault current value;

Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ;

use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or

The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value.

The calculation of zone selectivity interlocking time t _zsi based on the detected fault current value includes:

Calculate the zone selectivity interlocking time t _zsi , where t _zsi is proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, ; where A is a predetermined coefficient; I _SD is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical trip time, and the mechanical trip time is the time required for the circuit breaker to perform the tripping action . The calculation of the standby protection time t _sd based on the detected fault current value includes:

Calculate backup protection time of nth level circuit breaker

in proportional to the fault current threshold, is the area selective interlocking time of the n-1 level circuit breaker, t _mec is the mechanical tripping time; t _p is the predetermined time value.

A circuit breaker, including a fault current threshold setting unit, a time calculation unit and a tripping unit, wherein:

A fault current threshold value setting unit, used to set the fault current threshold value;

The time calculation unit is used to calculate the area selective chain time t _zsi and/or the standby protection time t _sd based on the detected fault current value when it is determined that the detected fault current value is not less than the fault current threshold value, wherein the area The selective interlocking time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value;

The tripping unit is used to judge whether an area selective interlocking input signal is received from the circuit breaker of the next stage within the area selective interlocking time t _zsi , and if so, when the backup protection time t _sd arrives, if a fault occurs If it still exists, it will trip; if not, it will trip after the zone selective interlocking time t _zsi arrives.

A time calculation unit, which is used to directly use the fault current value to calculate the zone selective interlocking time t _zsi and/or the backup protection time t _sd ;

Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ;

use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or

The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value.

The time calculation unit is used to calculate the area selective interlocking time t _zsi , wherein t _zsi is proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, ; Among them, A is a predetermined coefficient; I _sd is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical tripping time.

The time calculation unit for calculating the backup protection time t _sd based on the detected fault current value includes:

Calculating backup protection time of nth level circuit breaker

in proportional to the fault current threshold, is the area selective interlocking time of the n-1 level circuit breaker, t _mec is the mechanical tripping time; t _p is the predetermined time value.

A circuit breaker system comprising a first circuit breaker and a second circuit breaker, wherein the second circuit breaker is located downstream of the first circuit breaker;

The first circuit breaker is used to set the fault current threshold value, and when it is determined that the detected fault current value is not less than the fault current threshold value, calculate the zone selective chain time t _zsi and/or based on the detected fault current value Standby protection time t _sd , wherein the area selective chain time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value; and judging that in the area selection Whether the area selective interlocking signal from the second circuit breaker is received within the sex interlocking time t _zsi , if yes, trip if the fault still exists after the arrival of the backup protection time t _sd ; if not, in the area Trip after the selective chain time t _zsi arrives;

The second circuit breaker is configured to send an area-selective interlocking signal to the first circuit breaker when a short-circuit fault is detected.

The first circuit breaker is used to directly use the fault current value to calculate the zone selective interlocking time t _zsi and/or the backup protection time t _sd ;

Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ;

use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or

The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value.

A machine-readable storage medium storing instructions for causing a machine to execute any one of the above methods.

A computer program that, when the computer program is run on a machine, causes the machine to perform any one of the above-mentioned methods.

In the embodiment of the present invention, the fault current threshold value is set; when the non-last stage circuit breaker determines that the detected fault current value is not less than the fault current threshold value, the regional selective chain time is calculated based on the detected fault current value t _zsi and/or the backup protection time t _sd , wherein the area selectivity interlocking time t _zsi decreases with the increase of the detected fault current value, and the backup protection time t _sd decreases with the increase of the detected fault current value; judging the Whether the non-last level circuit breaker receives the area selective interlocking input signal from the next level circuit breaker within the said area selective interlocking time t _zsi , if yes, if the fault still exists after the said backup protection time t _sd arrives Then the first circuit breaker trips; if not, the non-last stage circuit breaker trips after the zone selective interlocking time t _{zsi is} reached.

It can be seen from the above that after applying the embodiment of the present invention, t _zsi and t _sd are no longer fixed values, and the embodiment of the present invention adjusts the area selective interlocking time t _zsi and the standby protection time t _sd based on the detected fault current value The size reduces the impact of thermal and electromagnetic effects on the lines/cables and circuit breakers in the system.

Description of drawings

Fig. 1 is an area-selective interlocking method of circuit breakers according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a circuit breaker according to an embodiment of the present invention.

Fig. 3 is a structural diagram of a circuit breaker system according to an embodiment of the present invention.

Fig. 4 is a structural diagram of a regioselective linkage system according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of the work flow of the circuit breaker in the system of FIG. 4 .

Detailed ways

In order to make the technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to illustrate the present invention, and are not intended to limit the protection scope of the present invention.

The embodiment of the present invention proposes an area-selective interlocking method of circuit breakers.

Fig. 1 is an area-selective interlocking method of circuit breakers according to an embodiment of the present invention.

As shown in Figure 1, the method includes:

Step 101: Set a fault current threshold value.

In the implementation manner of the present invention, the fault current threshold value may be firstly set for circuit breakers at all levels. The fault current threshold value may be related to the rated current of each circuit breaker, such as a predetermined multiple of the rated current.

The fault current can include various forms, for example, it can be short-circuit current or leakage current. For example, in one embodiment, when a short-circuit fault occurs, the fault current threshold value may be 10, 12, 15 or 20 times the rated current of the circuit breaker, and so on. In one embodiment, when a leakage fault occurs, the fault current threshold value may be 0.1, 0.2, 0.3, 0.4 or 0.5 times the rated current of the circuit breaker, and so on.

Those skilled in the art can realize that although some specific numbers are listed above to describe the multiple relationship between the fault current threshold value and the rated current, this description is only exemplary and is not used for the implementation of the present invention. The scope of protection is limited.

Step 102: When the non-last stage circuit breaker determines that the detected fault current value is not less than the fault current threshold value, calculate the regional selective interlocking time t _zsi and/or the backup protection time t _sd based on the detected fault current value, Among them, the zone selective chain time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value.

Here, the start calculation point of the zone selective interlocking time t _zsi and the backup protection time t _sd of the non-last stage circuit breaker may be the moment when the last stage circuit breaker detects a fault current.

In one embodiment, calculating the zone selectivity interlocking time t _zsi and/or the standby protection time t _sd based on the detected fault current value may specifically include:

(1) Calculate the zone selectivity chain time t _zsi and/or the backup protection time t _sd directly by using the fault current value.

For example, it can be set that t _zsi is directly proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, ; Among them, A is a predetermined coefficient; I _sd is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical tripping time.

Moreover, it is also possible to calculate the backup protection time of the nth level circuit breaker based on the detected fault current value in:

proportional to the fault current threshold, is the regional selective interlocking time of the n-1th level circuit breaker, t _mec is the mechanical tripping time (that is, the time required for the circuit breaker to perform the tripping action); t _p is the predetermined time value.

can be calculated in various ways For example, for the n-1 level circuit breaker, the formula can be used calculated because decreases with increasing fault current, so the calculated It also naturally decreases with increasing fault current.

(2) Using the change rate of the fault current value to calculate the zone selectivity chain time t _zsi and/or the standby protection time t _sd .

For example, it can be set that t _zsi is directly proportional to the fault current threshold value, and t _zsi is inversely proportional to the rate of change of the detected fault current value.

(3) Using the energy of the fault current value to calculate the zone selectivity chain time t _zsi and/or the standby protection time t _sd .

For example, it can be set that t _zsi is directly proportional to the fault current threshold value, and t _zsi is inversely proportional to the energy of the detected fault current value.

(4) Using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the standby protection time t _sd .

For example, it can be set that t _zsi is directly proportional to the fault current threshold value, and t _zsi is inversely proportional to at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value. Specifically, weight factors can be set for the three parameters of the fault current value, the rate of change of the fault current value, and the energy of the fault current value, and the area selective chain time t _zsi and/or the backup protection time t _sd are calculated by the weighting algorithm .

for example:

t _zsi = f(I _fault (t), I _fault '(t), I ² t); t _sd = f ₁ (I _fault (t), I _fault '(t), I ² t); where I _fault (t) is the fault current function, I _fault '(t) is the change rate function of the fault current value; I ² t is the energy function of the fault current value. The functions f(x) and f ₁ (x) can have various implementation forms.

Those skilled in the art can realize that although some specific functions are listed above to describe how to calculate the zone-selective interlocking time t _zsi and/or the standby protection time t _sd based on the detected fault current value, this description is only exemplary It is not intended to limit the protection scope of the embodiments of the present invention.

Step 103: Judging whether the non-last stage circuit breaker receives an area selective interlocking input signal from the next stage circuit breaker within the area selective interlocking time t _zsi , if yes, arrives at the backup protection time t _sd Afterwards, if the fault still exists, the non-last stage circuit breaker will trip; if not, the non-final stage circuit breaker will trip after the zone selective interlocking time t _zsi arrives.

Specifically, the circuit breaker can be tripped by a trip unit. The release is a device that is mechanically connected (or integrated) with the circuit breaker to release the holding mechanism and automatically disconnect the circuit breaker. The trip unit can include electromagnetic trip unit, thermal magnetic trip unit and electronic trip unit. Specifically, the electromagnetic release only provides magnetic protection, that is, short-circuit protection. When the current is large enough, the magnetic field force generated overcomes the reaction force spring to attract the armature and strike the drawbar, thereby driving the mechanism to cut off the circuit. Thermal magnetic trip units provide magnetic protection and thermal protection, thermal protection is also overload protection. Generally speaking, thermal-magnetic releases are used to provide short-circuit and overload protection in the circuit. Only in some special occasions, electromagnetic releases are used to provide short-circuit protection, while other components (such as thermal relays) provide overload protection. The electronic trip unit can have all the above functions and can be easily set. The electronic trip unit is a circuit composed of electronic components, which detects the current of the main circuit, amplifies and pushes the tripping mechanism.

It can be seen that when there is a relatively high fault current in the circuit breaker system, the embodiment of the present invention reduces the thermal effect and electromagnetic effect on the lines/cables in the system by reducing the area selective chaining time t _zsi and the backup protection time t _sd and adverse effects caused by circuit breakers.

Based on the above detailed analysis, the embodiment of the present invention also proposes a circuit breaker.

Fig. 2 is a schematic structural diagram of a circuit breaker according to an embodiment of the present invention.

As shown in Figure 2, the circuit breaker includes a fault current threshold setting unit 201, a time calculation unit 202 and a tripping unit 203, wherein:

The fault current threshold setting unit 201 is used to set the fault current threshold;

The time calculation unit 202 is used to calculate the area selective chain time t _zsi and/or the standby protection time t _sd based on the detected fault current value when it is determined that the detected fault current value is not less than the fault current threshold value, wherein the area The selective interlocking time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value;

The tripping unit 203 is used to judge whether an area selective interlocking input signal is received from the next-level circuit breaker within the area selective interlocking time t _zsi , and if so, after the standby protection time t _sd arrives, the fault occurs If it still exists, it will trip; if not, it will trip after the zone selective interlocking time t _zsi arrives.

Obviously, the above functions of the fault current threshold value setting unit 201 and the time calculation unit 202 can be realized by programs. Meanwhile, hardware may also be used to implement the above functions of both. In one embodiment: the fault current threshold value setting unit 201 may specifically be a comparator or various memories for saving the fault current threshold value. The time calculation unit 202 may specifically be a microcontroller (MCU). The MCU can compare the detected fault current value with a fault current threshold value stored in a comparator or a memory, and calculate the zone selective interlocking time t _zsi and/or the backup protection time t _sd .

The trip unit 203 may include a trip unit and a control unit for controlling the action of the trip unit 203 . . The trip unit receives the zone-selective interlocking time t _zsi and/or the backup protection time t _sd from the MCU, and uses the trip unit to perform a specific tripping operation.

In one embodiment:

A time calculation unit 202, used to directly use the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the standby protection time t _sd ;

Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ;

use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or

The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value.

In one embodiment:

The time calculation unit 202 is used to calculate the area selective chain time t _zsi , wherein t _zsi is proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, ; Among them, A is a predetermined coefficient; I _SD is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical tripping time.

In one embodiment:

The time calculation unit 202, which is used to calculate the standby protection time t _sd based on the detected fault current value, includes:

Calculating backup protection time of nth level circuit breaker

in proportional to the fault current threshold, is the regional selective interlocking time of the n-1th level circuit breaker, t _mec is the mechanical tripping time; t _p is the predetermined time value.

The circuit breaker according to the embodiment of the present invention may be embodied in various types. For example, according to the operation mode, it can be implemented as: electric operation, energy storage operation and manual operation, etc.; according to the structure, it can be implemented as universal type and molded case type. According to the type of use, it can be implemented as: selective type and non-selective type; according to the arc extinguishing medium, it can be implemented as: oil-immersed type, sulfur hexafluoride, vacuum type and air type, etc.; according to the action speed, it can be implemented The implementation is: fast type and ordinary type; according to the number of stages, it can be implemented as: single-stage, two-stage, three-stage and four-stage, etc.; according to the installation method, it can be implemented as: plug-in type, fixed type and drawer type, etc.

More specifically, the circuit breaker in the embodiment of the present invention may be implemented as an air circuit breaker (ACB, air circuit breaker) or a molded case circuit breaker (MCCB, molded case circuit breaker). MCCB circuit breakers can be located downstream of ACBs to further protect and isolate sections of the power distribution system. MCCB circuit breakers can have various available capacities, and are usually arranged in multiple layers or stages, and multiple MCCBs are arranged in each layer.

Based on the above detailed analysis, the embodiment of the present invention also proposes a circuit breaker system.

Fig. 3 is a structural diagram of a circuit breaker system according to an embodiment of the present invention. A circuit breaker system may be provided in the power distribution system.

As shown in Fig. 3, the system includes a power supply, a first circuit breaker, a second circuit breaker and a load, wherein the second circuit breaker is located at the lower stage of the first circuit breaker. A circuit connected to a circuit breaker is called a protected circuit.

The first circuit breaker 301 is used to set the fault current threshold value, and when it is determined that the detected fault current value is not less than the fault current threshold value, calculate the zone selective chain time t _zsi and/or based on the detected fault current value or the standby protection time t _sd , wherein the area selectivity chain time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value; and it is judged that in the area whether to receive the area selective interlocking signal from the second circuit breaker within the selective interlocking time _{t zsi} ; Trip after the regional selective chain time t _zsi arrives;

The second circuit breaker 302 is configured to send an area selective chain signal to the first circuit breaker 301 when a short circuit fault is detected.

When the second circuit breaker 302 is the last stage circuit breaker, since there is no lower stage circuit breaker, its t _zsi is zero. When the second circuit breaker 302 is not the final stage circuit breaker, t _zsi and t _sd of the second circuit breaker 302 can be calculated in a manner similar to that of the first circuit breaker 301 .

In one embodiment:

The first circuit breaker 301 is used to directly use the fault current value to calculate the zone selective interlocking time t _zsi and/or the backup protection time t _sd ;

Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ;

use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or

The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value.

In one embodiment:

The first circuit breaker 301 is used to calculate the zone selective interlocking time t _zsi , wherein t _zsi is directly proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, ; Among them, A is a predetermined coefficient; I _SD is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical tripping time.

In one embodiment: the first circuit breaker 301 is used to calculate the backup protection time of the nth level circuit breaker

in proportional to the fault current threshold, is the regional selective interlocking time of the (n-1) level circuit breaker, t _mec is the mechanical tripping time; t _p is the predetermined time value.

In the circuit breaker system proposed by the present invention, the I protection of the non-final circuit breaker can be enabled or disabled. When the I protection of the non-last stage circuit breaker is enabled, a fault current threshold value is set for I protection, if the non-final stage circuit breaker determines that the detected fault current value is greater than the fault current threshold value set for I protection , then the non-last stage circuit breaker performs the existing operations related to I protection.

In the circuit breaker system proposed by the present invention, when the I protection of the non-last stage circuit breaker is disabled, only when it is determined that the detected fault current value is not less than the fault current threshold value proposed by the embodiment of the present invention, the The zone-selective interlocking function of non-last-stage circuit breakers is only valid. Moreover, when the detected fault current value reaches the fault current threshold value, both the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd will be dynamic.

Table 1 is a table of exemplary values of zone selective interlocking time t _zsi and backup protection time t _sd of a 6-stage circuit breaker system.

According to the order from the upper level to the lower level, the circuit breakers are Q11, Q21, Q31, Q41 and Q51, among which Q51 is the last level circuit breaker. The fault current threshold value of each level of circuit breaker can be set as a predetermined multiple of the rated current of the level of circuit breaker. For example, suppose the fault current I _fault is 30KA, t _mec is 35ms, and the maximum value of t _zsi is assumed to be 50ms, then even at very high circuit currents, the dynamic range of t _zsi is between 35ms and 50ms. Moreover, t _sd of Q51 is 0; t _sd of Q41 is the sum of t _zsi of Q51, mechanical tripping time (for example, 35ms) and allowable error (15ms), which is equal to 89ms.

The parameters of each level circuit breaker are as follows:

Table 1

In Table 1, both t _zsi and t _sd are related to the fault current. When the fault current changes, the values of t _zsi and t _sd will also change.

Based on the detailed analysis above, a specific embodiment of the present invention will be described below.

Fig. 4 is a structural diagram of a regioselective linkage system according to an embodiment of the present invention.

As shown in FIG. 4 , the system includes a power source 401 , a circuit breaker 402 , a circuit breaker 403 and a circuit breaker 404 , and each circuit breaker has regional selective chain protection connections. The circuit breaker 402 is directly connected to the power supply 401 and is located at the uppermost stage; the circuit breaker 403 is located at the upper stage of the circuit breaker 404 and at the lower stage of the circuit breaker 402 .

The fault current threshold for this stage can be set in the circuit breaker 403 . When a short-circuit situation occurs in the system, if the circuit breaker 403 judges that the detected fault current value is not less than the fault current threshold value, the circuit breaker 403 calculates its own regional selective chain time t _zsi and/or based on the detected fault current value Or the backup protection time t _sd , where the zone selectivity chain time t _zsi decreases as the detected fault current value increases, and the backup protection time t _sd decreases as the detected fault current value increases. Circuit breaker 403 also judges whether to receive the area selective interlocking input signal from circuit breaker 404 within the calculated area selective interlocking time t _zsi , if so, after the calculated standby protection time t _sd arrives, if the fault still exists , the circuit breaker 403 trips; if not, the circuit breaker 403 trips after the calculated zone selectivity interlocking time t _zsi arrives.

FIG. 5 is a schematic diagram of the working flow of the circuit breaker 403 in the system of FIG. 4 .

As shown in Figure 5, the method includes:

Step 501: When a fault occurs, the circuit breaker 403 sends a ZSI signal to the circuit breaker 402 at the upper level.

Step 502: The circuit breaker 403 judges whether the detected fault current value is not less than the preset fault current threshold value, if yes, calculate step 503 and subsequent steps, otherwise return to step 502.

Step 503: The circuit breaker 403 calculates the zone selective interlocking time t _zsi and/or the backup protection time t _sd based on the detected fault current value, wherein the zone selective interlocking time t _zsi decreases as the detected fault current value increases, The backup protection time t _sd decreases as the detected fault current value increases. The specific calculation method of the zone selectivity chain time t _zsi and/or the standby protection time t _sd is described above, and will not be repeated here.

Step 504: the circuit breaker 403 judges whether the ZSI signal sent by the circuit breaker 404 located at the lower level is received within the regional selectivity interlocking time t _zsi , if yes, then perform step 505 and its subsequent steps, if not then perform step 506 and its next steps.

Step 505: The circuit breaker 403 judges whether the standby protection time t _sd has ended, if yes, execute step 507 and subsequent steps, otherwise return to execute step 502.

Step 506: The circuit breaker 403 judges whether the zone selectivity chain time t _zsi has ended, if yes, execute step 508, otherwise return to execute step 502.

Step 507: Determine whether the fault still exists, if yes, execute step 508, otherwise return to execute step 502.

Step 508: The circuit breaker 403 trips.

The region-selective interlocking method of circuit breakers proposed in the embodiments of the present invention may be implemented in various forms. For example, the region-selective interlocking method of the circuit breaker can be written as a plug-in program installed in various computing devices according to a certain standard application program interface, or it can be packaged as an application program for users to download and use by themselves. When written as a plug-in program, it can be implemented as various plug-in forms such as ocx, dll, and cab. The regional selective chaining method of the circuit breaker proposed in the embodiment of the present invention can also be implemented through specific technologies such as Flash plug-in, RealPlayer plug-in, MMS plug-in, MIDI stave plug-in, ActiveX plug-in.

The area-selective interlocking method of circuit breakers proposed in the embodiments of the present invention can be stored on various storage media by means of storing instructions or instruction sets. These storage media include but are not limited to: floppy disk, CD, DVD, hard disk, flash memory, U disk, CF card, SD card, MMC card, SM card, Memory Stick (Memory Stick), xD card, etc.

In addition, the regional selective chaining method of circuit breakers proposed in the embodiment of the present invention can also be applied to storage media based on flash memory (Nand flash), such as U disk, CF card, SD card, SDHC card, MMC card, SM card , memory stick, xD card, etc.

To sum up, in the embodiment of the present invention, the fault current threshold value is set; when the non-last stage circuit breaker judges that the detected fault current value is not less than the fault current threshold value, it calculates based on the detected fault current value Zone-selective interlocking time t _zsi and/or backup protection time t _sd , where zone-selective interlocking time t _zsi decreases with detected fault current value and backup protection time t _sd increases with detected fault current value and reduce; judge whether the non-last stage circuit breaker receives the zone selective chain input signal from the next stage circuit breaker within the zone selectivity chain time t _zsi , if yes, then in the backup protection time t _sd If the fault still exists after arrival, the non-last stage circuit breaker will trip; if not, the non-final stage circuit breaker will trip after the zone selective interlocking time t _zsi arrives. It can be seen that after applying the embodiment of the present invention, t _zsi and t _sd are no longer fixed values. When there is a high fault current in the circuit breaker system, the embodiment of the present invention reduces the area selective chain time t _zsi and the backup protection time t _sd , reducing the influence of thermal and electromagnetic effects on the lines/cables in the system.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. A region-selective interlocking method of a circuit breaker, characterized in that, comprising: Set fault current thresholds for circuit breakers at all levels; When the non-last stage circuit breaker determines that the detected fault current value is not less than the fault current threshold value, it calculates an area selective chain time t _zsi and a backup protection time t _sd based on the detected fault current value, where the The zone selectivity interlocking time t _zsi decreases as the detected fault current value increases, and the backup protection time t _sd decreases as the detected fault current value increases; Judging whether the non-last-level circuit breaker receives an area-selective interlocking input signal from the next-level circuit breaker within the area-selective interlocking time _tzsi , If yes, if the fault still exists after the standby protection time t _sd arrives, the non-last stage circuit breaker trips; If not, the non-last stage circuit breaker trips after the zone selective interlocking time t _{zsi has been} reached. 2. The area selective interlocking method according to claim 1, characterized in that, the calculation of area selective interlocking time t _zsi and/or standby protection time t _sd based on the fault current value detected comprises: Calculating zone selective interlocking time t _zsi and/or backup protection time t _sd directly using fault current value; Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value. 3. area selective interlocking method according to claim 1, is characterized in that, described calculation area selective interlocking time t _zsi based on the detected fault current value comprises: Calculate the zone selectivity interlocking time t _zsi , where t _zsi is proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, Among them, A is a predetermined coefficient; I _sd is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical tripping time. 4. regional selective interlocking method according to claim 1, is characterized in that, described calculation standby protection time t _sd based on the detected fault current value comprises: Calculate backup protection time of nth level circuit breaker in It is proportional to the fault current threshold value, is the area selective interlocking time of the n-1 level circuit breaker, t _mec is the mechanical tripping time; t _p is the predetermined time value. 5. A circuit breaker comprising a fault current threshold setting unit, a time calculation unit and a tripping unit, wherein: a fault current threshold setting unit configured to set fault current thresholds for circuit breakers at all levels; A time calculation unit, which is configured to calculate the zone selective interlocking time t _zsi and the standby protection time t _sd based on the detected fault current value when it is determined that the detected fault current value is not less than the fault current threshold value, wherein the zone The selective interlocking time t _zsi decreases with the increase of the detected fault current value, and the standby protection time t _sd decreases with the increase of the detected fault current value; a trip unit configured to judge whether an area selective interlocking input signal is received from a circuit breaker of the next stage within said area selective interlocking time t _zsi , If yes, trip if the fault still exists after the standby protection time t _sd arrives; If not, tripping occurs after the zone selectivity interlocking time t _{zsi has been} reached. 6. The circuit breaker according to claim 5, wherein the time calculation unit is configured as: Calculating zone selective interlocking time t _zsi and/or backup protection time t _sd directly using fault current value; Using the rate of change of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; use the energy of the fault current value to calculate the zone selectivity interlocking time t _zsi and/or the backup protection time t _sd ; or The zone selectivity interlocking time t _zsi and/or the backup protection time t _sd are calculated using at least two of the three parameters of the fault current value, the rate of change of the fault current value and the energy of the fault current value. 7. The circuit breaker of claim 5, wherein: The time calculation unit is used to calculate the area selective chain time t _zsi , where t _zsi is proportional to the fault current threshold value, and t _zsi is inversely proportional to the detected fault current value, Among them, A is a predetermined coefficient; I _sd is the fault current threshold value; I _fault is the detected fault current value; t _mec is the mechanical tripping time. 8. The circuit breaker of claim 5, wherein: The time calculation unit is used to calculate the standby protection time t _sd based on the detected fault current value, including: Calculate backup protection time of nth level circuit breaker in It is proportional to the fault current threshold value, is the area selective interlocking time of the n-1 level circuit breaker, t _mec is the mechanical tripping time; t _p is the predetermined time value. 9. A circuit breaker system, comprising a first circuit breaker and a second circuit breaker, wherein the second circuit breaker is located at the lower stage of the first circuit breaker; characterized in that, The first circuit breaker is the circuit breaker according to any one of claims 5 to 8; The second circuit breaker is configured to send an area-selective interlocking signal to the first circuit breaker when a short-circuit fault is detected.