KR101336067B1 - Apparatus for displaying abnormality of power system - Google Patents

Abstract

The present invention relates to a power system abnormality display device, and the power system abnormality display device according to the present invention includes an opening detection unit (110) for monitoring the input voltage input from the secondary side of the current transformer to sense the opening of the secondary side terminal of the current transformer. And a voltage abnormality detection unit 120 for monitoring whether the voltage of the secondary terminal of the transformer is out of a predetermined ratio from the threshold voltage by detecting the voltage of the secondary terminal of the transformer, and receiving the breaker auxiliary voltage as an input. Auxiliary voltage abnormality detection unit 130 that detects deviation from the threshold voltage by a predetermined ratio or more, and when the secondary terminal of the current transformer is opened, the secondary terminal of the current transformer is short-circuited and the secondary terminal of the current transformer is short-circuited and defective contact and the secondary side of the transformer. Relay unit 140 for operating the alarm according to the terminal and breaker auxiliary voltage abnormality, and the current flow A display unit 150 indicating an opening of the transformer and a secondary voltage of the secondary terminal of the transformer; and when the current transformer secondary terminal opening is maintained for a predetermined time through the open detector, the relay unit is controlled to short-circuit the secondary terminal of the current transformer. And a control unit 170 to control the display unit to display a fault, and to detect an abnormality in the transformer secondary terminal voltage and the breaker auxiliary voltage by the voltage abnormality detecting unit and the auxiliary voltage abnormality detecting unit. Characterized in that.

Description

Power system abnormal display device {APPARATUS FOR DISPLAYING ABNORMALITY OF POWER SYSTEM}

The present invention relates to a power system abnormality display device for detecting and displaying an abnormality of a current transformer opening and contact failure of a power system and an abnormality of a transformer secondary terminal voltage and a breaker auxiliary voltage (breaker trip voltage), respectively.

In general, a current transformer (CT) is a type of transformer and is a device for extending the measuring range of an alternating current ammeter by obtaining a small current proportional to the number of turns from a large current of an alternating current. Such a current transformer is wound around a primary coil with a small number of turns and a secondary coil with a large number of turns on an iron core such as a transformer. The secondary coil connects an ammeter, a power meter, and a relay to the secondary coil. The current ratio of the current flowing through the primary coil and the secondary coil is inversely proportional to the turn ratio of the primary coil and the secondary coil. The rating of the primary current varies from tens of amps to several thousand amps, but the rating of the secondary current is mostly 5 amps (A).

On the other hand, current transformers are different from transformers, so it is safe to short the secondary terminals, but it is dangerous to open them. This is because when the secondary terminal is opened, the primary current magnetizes all the iron cores so that the iron cores saturate and generate heat, which may cause damage to the coil, explosion risk of the current transformer, and risk of electric shock. Therefore, if the current circuit is opened inside or outside the ammeter, power meter, or relay connected to the secondary coil of the current transformer, or if the secondary coil of the current transformer is open due to other reasons, the current state is immediately sensed and shut off. That is, it is necessary to connect a circuit having a function of immediately shorting the open secondary terminal to the secondary side of the current transformer.

Conventional current transformer open detection device has been proposed to prevent short-circuit current transformer and electric shock by short-circuit immediately when the current transformer secondary terminal is opened.

However, the conventional current transformer open detection device is difficult to detect the occurrence of contact faults that cause the current transformer secondary terminal opening and the voltage abnormality in each of the secondary side of the transformer, not the opening of the current transformer secondary terminals.

In addition, according to the related art, a breaker auxiliary voltage (trip voltage) abnormality cannot be detected without using a transformer secondary terminal voltage detection device.

-Prior Document 1: Korean Laid-Open Patent Publication No. 2013-0039475 (April 22, 2013) An overcurrent relay for diagnosing an open state of a secondary circuit of a current transformer and a method thereof

The present invention has been made to solve the problems of the prior art, a power system abnormality display device that can detect and display the contact failure and opening of the secondary terminal of the current transformer by monitoring the voltage input from the secondary terminal of the current transformer To provide.

In addition, the present invention provides a power system abnormality display device capable of monitoring the voltage of each phase of the secondary side of the transformer to display a phase in which a voltage abnormality has occurred.

In addition, the present invention is to provide a power system abnormality display device that monitors the breaker auxiliary voltage separately from the voltage of each phase of the transformer secondary side to turn on and display the light emitting element when an error occurs in the breaker auxiliary voltage.

In order to solve the above problems, the power system fault display device according to the present invention monitors the input voltage input from the secondary terminal of the current transformer to detect the opening of the secondary terminal of the current transformer 110 and the transformer secondary side The voltage abnormality detection unit 120 that detects whether the voltage of the secondary terminal of the transformer deviates by a predetermined ratio from the threshold voltage by monitoring the voltage of the terminal, and receives the circuit breaker auxiliary voltage as an input, and the input circuit breaker auxiliary voltage is constant from the threshold voltage. Auxiliary voltage abnormality detection unit 130 for detecting whether the ratio is more than the ratio, and when the secondary terminal of the current transformer is opened, the secondary terminal of the current transformer is short-circuited and the secondary terminal terminal short circuit and contact failure and the transformer secondary terminal and breaker auxiliary Relay unit 140 for operating the alarm according to the voltage abnormality, opening and transformer of the current transformer The display unit 150 displaying the secondary side terminal voltage abnormality, and when the current transformer secondary terminal opening is maintained for a predetermined time through the opening detection unit, the relay unit is controlled to short-circuit the secondary terminal of the current transformer and the display unit is broken. And a control unit 170 for controlling the display unit to display occurrence of voltage abnormality when the voltage abnormality detecting unit and the auxiliary voltage abnormality detecting unit detect an abnormality of the transformer secondary terminal voltage and the breaker auxiliary voltage. do.

The open detector 110 may include an overvoltage protection unit 111 that prevents overvoltage from being input to an input terminal directly connected to the secondary terminal of the current transformer, and adjusts an amplitude of an input voltage input through the input terminal at a predetermined ratio. An input voltage attenuator 112 for attenuating the voltage, an input voltage attenuated by the input voltage attenuator 112, and a comparison unit 113 for outputting a comparison result, and a comparison result; The light emitting device is turned on, and the light receiving device receives an optical signal output from the light emitting device, converts the light signal into an electric signal, and outputs the electrical signal, and generates a pulse according to the electric signal output from the insulating device. It characterized in that it comprises a short pulse generator 115.

The voltage abnormality detection unit includes an overvoltage protection unit 121 for protecting a circuit by bypassing an overvoltage when an overvoltage is input to an input terminal directly connected to a secondary terminal of a transformer, and an analog for converting an input voltage input through the input terminal into a digital signal. A digital converter (hereinafter referred to as an AC / DC converter) 122, a pulse width modulator 123 for modulating the pulse width of the input voltage converted by the AC / DC converter, and the pulse width modulation. The light emitting element is turned on according to the rough input voltage, and the light receiving element is turned on by the light emitting element being turned on to output an electric signal, and the electric signal output from the insulator 124 is converted into a DC signal. It characterized in that it comprises a direct current (DC) converter (125).

When the control unit detects the opening of the secondary side of the current transformer, the controller controls the relay unit to short-circuit an input terminal of the open detection unit connected to the secondary side terminal of the current detecting unit and a relay connection terminal.

The control unit, by operating the relay unit is connected to the current transformer short-circuit alarm contact and the relay connection terminal, characterized in that the alarm to open the current transformer.

The display unit may include respective light emitting devices for indicating an open detection and a failure of the secondary terminal of the current transformer, a failure relay operation, and a terminal voltage abnormality or a breaker auxiliary voltage abnormality.

As described above, the power system fault display apparatus according to the embodiment of the present invention may monitor and detect a voltage input from the secondary terminal of the current transformer to detect and display contact failure and opening of the secondary terminal of the current transformer.

In addition, the present invention can monitor the voltage of each phase of the transformer secondary side to display a phase in which a voltage abnormality has occurred.

In addition, the present invention monitors the breaker auxiliary voltage separately from the voltage of each phase of the transformer secondary side, and when an abnormality occurs in the breaker auxiliary voltage, the light emitting device may be turned on and displayed.

1 is a block diagram illustrating an internal power system abnormality display device according to an exemplary embodiment of the present invention.
FIG. 2 is a circuit diagram of the open detector shown in FIG. 1. FIG.
3 is a circuit diagram of the voltage abnormality detecting unit and the auxiliary voltage abnormality detecting unit shown in FIG. 1;
4 is a circuit diagram illustrating a relay unit and a display unit illustrated in FIG. 1.
FIG. 5 is a circuit diagram illustrating the relay unit illustrated in FIG. 4. FIG.
FIG. 6 is a circuit diagram illustrating the display unit illustrated in FIG. 4. FIG.

Hereinafter, a power system abnormality display device according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating an internal power system fault display device according to an exemplary embodiment of the present invention, FIG. 2 is a circuit diagram of the open detector shown in FIG. 1, and FIG. 3 is a voltage abnormality detector shown in FIG. 1. And a circuit diagram of the auxiliary voltage abnormality detecting unit, FIG. 4 is a circuit diagram showing the relay unit and the display unit shown in FIG. 1, FIG. 5 is a circuit diagram showing the relay unit shown in FIG. 4, and FIG. It is a circuit diagram showing the illustrated display portion.

As shown in FIG. 1, the power system abnormality display device 100 according to an exemplary embodiment of the present invention may include an open detector 110, a voltage abnormality detector 120, an auxiliary voltage abnormality detector 130, and a relay unit 140. , A display unit 150, a power supply unit 160, and a controller 170. The input terminal of the power system fault display device 100 is connected to the secondary terminal of the current transformer and the transformer to receive the voltage induced when the secondary terminal of the current transformer is opened as an input signal, and the voltage of the secondary terminal of the transformer as an input signal. Receive. In addition, the power system abnormality display device 100 monitors an input signal of each phase (R phase, S phase, T phase) and detects whether the current transformer is open or contact failure and / or voltage abnormality of the secondary terminal of the transformer. .

The open detector 110 receives the voltage of the secondary terminal of the current transformer as an input, and recognizes that the input voltage is a contact failure when the input voltage is detected above the threshold voltage, and opens the secondary terminal of the current transformer when the input voltage is higher than the threshold voltage for a predetermined time. Recognize.

The open detector 110 includes an overvoltage protector 111, an input voltage attenuator 112, a comparator 113, an insulator 114, and a short pulse generator 115. In the following, since the circuits of the R phase, the S phase, and the T phase are all the same, a description will be given based on the R phase of the current transformer secondary terminal.

The overvoltage protection unit 111 is directly connected to the secondary terminal of the current transformer corresponding to each of the R phase, the S phase, and the T phase, thereby preventing overvoltage from being input to the input terminal of the open detection unit 100. The overvoltage protection unit 111 may be implemented as varistors INR1 and INR2. The overvoltage protection unit 11 protects the circuit by short-circuit such that current flows to the ground through a varistor having a low impedance when the secondary terminal of the current transformer is opened and the induced voltage becomes higher than a threshold voltage.

The input voltage attenuation unit 112 adjusts the amplitude of the input voltage input from the input terminal to attenuate and output the voltage at a predetermined ratio.

The comparison unit 113 checks whether the input voltage attenuated by the input voltage attenuation unit 112 is greater than or equal to the threshold voltage. That is, the comparator 113 compares the attenuated input voltage with a threshold voltage and outputs a comparison result. As shown in FIG. 2, the comparator 113 may include an op-amp (LM358) and a resistor (R7). In this case, a buffer ultra-short amplifier may be further included between the input voltage attenuator 112 and the comparator 113 to amplify the input voltage adjusted by the input voltage attenuator 112 according to a level.

The insulating unit 114 may be configured using a photocoupler (TLP181) including a light emitting element and a light receiving element. The insulator 114 lights the light emitting device according to the output of the comparator 113, and the light receiving device receives an optical signal output from the light emitting device and converts the light signal into a predetermined electric signal (for example, a voltage).

The short pulse generator 116 generates a pulse according to the output electrical signal when the light receiving element is turned on by light emission of the light emitting element of the insulator 114 and an electric signal of a predetermined size is output from the insulator 114. To print.

The voltage abnormality detection unit 120 receives the voltage of the transformer (PT) secondary terminal of each phase (R phase, S phase, T phase), and monitors the input voltage to input the voltage of the secondary terminal. If the threshold voltage is out of a certain ratio, a signal indicating the voltage abnormality is output. The voltage abnormality detector 120 includes an overvoltage protection unit 121, an analog / digital converter (AC / DC) converter 122, a pulse width modulator 123, and an insulation unit 124. And a DC converter 125. In the following, since the circuits of the R phase, the S phase, and the T phase are all the same, a description will be given based on the R phase of the secondary terminal of the transformer.

The overvoltage protection unit 121 is for preventing overvoltage from being input to the input terminal of the voltage abnormality detection unit 120 and may be configured as a zener diode. The overvoltage protection unit 121 bypasses the zener diode when a noisy overvoltage is applied between the input voltage of each transformer secondary side and ground.

When the AC / DC converter 122 receives the voltage of the transformer secondary terminal, the AC / DC converter 122 converts the input analog input voltage into a digital signal.

The pulse width modulator 123 modulates the pulse width of the input voltage converted by the AC / DC converter 122. The pulse width modulator 123 outputs a high ('H') signal when the converted input voltage is greater than or equal to a threshold voltage, and outputs a low ('L') signal when the converted input voltage is less than or equal to a threshold voltage. The width is converted and output as a digital signal. This is for transmitting a digital signal for lighting the light emitting device of the insulating unit 124 to be described later.

The insulation unit 124 includes a light emitting device that is turned on or off according to an input voltage modulated by the pulse width modulator 123, and includes a light receiving device that receives an optical signal output from the light emitting device and converts the light signal into an electrical signal. do. The insulating unit 124 may be configured using a photocoupler TLP181 including a light emitting element and a light receiving element.

The DC converter 125 converts an electric signal (AC signal) output from the insulation unit 124 into a DC signal and outputs the DC signal. The DC converter 125 is configured using two op amps LM833.

The auxiliary voltage abnormality detection unit 130 receives a circuit breaker auxiliary voltage, which is a direct current (DC) voltage, as an input and detects an abnormality of the circuit breaker auxiliary voltage. That is, the auxiliary voltage abnormality detecting unit 130 determines that the auxiliary voltage abnormality is greater than the auxiliary voltage when the breaker auxiliary voltage is out of the threshold voltage by a predetermined ratio or more. The auxiliary voltage abnormality detection unit 130 includes an overvoltage protection unit 131, a pulse width modulator 133, an insulation unit 134, and a DC converter 135. The overvoltage protection unit 131, the pulse width modulator 133, the insulation unit 134, and the DC converter 135 of the auxiliary voltage abnormality detection unit 130 may include the overvoltage protection unit 121 of the voltage abnormality detection unit 120, Since the operation is the same as the pulse width modulator 123, the insulator 124, and the DC converter 125, a detailed description thereof will be omitted.

According to the present invention, the breaker auxiliary voltage abnormality detecting unit 130 may be provided without using the voltage abnormality detecting unit 120. The auxiliary voltage abnormality detection unit 130 monitors the voltage applied between the DC voltage input terminal and the ground terminal common, and if the voltage between the DC voltage input terminal and the ground terminal deviates from the threshold voltage by a predetermined ratio or more, The relay between the alarm contact point and the relay connection terminal is turned on to turn on the DC voltage relay output LED.

When the secondary terminal of the current transformer is opened, the relay unit 140 turns on the relay connected to the open terminal to the ON state and connects the corresponding terminal to the relay connection terminal to short-circuit the secondary terminal of the current transformer. As shown in FIG. 4, the relay unit 140 turns on the relay by turning on the photocoupler ISO17 from the voltage applied to 5DV to short-circuit the secondary terminal of the current transformer. Therefore, it is possible to prevent current transformer burnout and electric shock.

The display unit 150 displays a short circuit, a fault, a fault relay operation of the current transformer, a voltage abnormality of the secondary terminal of the transformer, and a breaker auxiliary voltage abnormality, respectively, and includes a plurality of light emitting diodes (LEDs). The display unit 150 is composed of three LEDs (SET-LED, DETECTING-LED, and RELAY) respectively indicating short-circuit, failure and failure relay operation of the secondary terminal of the current transformer for each phase.

In addition, the display unit 150 includes one LED for each phase indicating whether the voltage of the transformer secondary terminal is abnormal. That is, when monitoring the secondary terminal voltage of the three-phase transformer, the display unit 150 is an LED indicating the voltage of the R phase, S phase, T phase abnormality (R phase VOLT RELAY output display LED, S phase VOLT RELAY output display LED, T Phase VOLT RELAY output LED). In addition, the display unit 150 includes one LED (DC VOLT RELAY output display LED) indicating the breaker auxiliary voltage or more.

The power supply unit 160 supplies an analog voltage and / or a digital voltage of 90V or more and 260V or less to the power system abnormality display device 100.

The control unit 170 detects when the input voltage input from the secondary terminal of the current transformer is greater than or equal to the threshold voltage and turns on the detection LED of the display unit 150. At this time, the controller 170 controls the relay unit 140 to operate a relay between the CT contact bad signal contact and the relay connection terminal.

The controller 170 turns on the fault LED (SET-LED) and operates the relay unit 140 when the voltage of the secondary terminal of the current transformer is maintained for a predetermined time (for example, 3 seconds) above the threshold voltage. Connect between input terminal and relay connection terminal of to form a loop on the secondary side of current transformer. That is, the controller 170 short-circuits the current transformer secondary terminal when the opening of the current transformer secondary terminal is detected through the open detector 110. The controller 170 turns off the detection LED when the current transformer secondary terminal is short-circuited, and the relay between the CT short-circuit alarm contact point and the relay connection terminal is turned off.

In addition, the control unit 170 monitors the transformer PT secondary side terminal voltages (R phase voltage, S phase voltage, and T phase voltage) through the voltage abnormality detection unit 120, and the transformer secondary terminal voltage is reduced from the threshold voltage. If a certain ratio is out of the range, the relay between the voltage alarm contact point and the relay connection terminal is turned on to turn on the voltage error indication LED of the phase in which the voltage error occurs.

In addition, the control unit 170 monitors the circuit breaker auxiliary voltage through the auxiliary voltage abnormality detection unit 130, and turns on the relay between the voltage alarm contact point and the relay connection terminal when the circuit breaker auxiliary voltage deviates by a predetermined ratio or more from the threshold voltage. Control 150 to turn on the auxiliary voltage error display LED.

The power system fault display apparatus according to the present invention includes an interlocking interlock terminal electrically connected between a plurality of current transformers to determine whether one of the current transformers is open.

100: power system abnormal display
110: open detection unit
120: voltage abnormality detection unit
130: auxiliary voltage error detection unit
140: relay unit
150:
160:
170:

Claims (6)

An opening detection unit 110 for monitoring an input voltage input from the current transformer secondary terminal and detecting an opening of the current transformer secondary terminal;
A voltage abnormality detection unit 120 for monitoring a voltage of the secondary terminal of the transformer and detecting whether the voltage of the secondary terminal of the transformer deviates by a predetermined ratio or more from a threshold voltage;
An auxiliary voltage abnormality detection unit 130 which receives a circuit breaker auxiliary voltage as an input and detects whether the received circuit breaker auxiliary voltage deviates by a predetermined ratio or more from a threshold voltage;
A relay unit 140 which short-circuits the secondary terminal of the current transformer and operates an alarm according to the transformer secondary terminal short-circuit and contact failure and the transformer secondary terminal and breaker auxiliary voltage abnormalities when the secondary terminal of the current transformer is opened;
A display unit 150 for displaying the opening of the current transformer and an abnormal voltage of a secondary terminal of the transformer;
If the current transformer secondary terminal opening is maintained for a predetermined time through the opening detection unit, the relay unit is controlled to short-circuit the secondary terminal of the current transformer and the display unit is displayed to indicate a fault. The voltage abnormality detecting unit and the auxiliary voltage abnormality detecting unit And a control unit (170) for controlling the display unit to display the occurrence of voltage abnormality when detecting an abnormality of the transformer secondary terminal voltage and the breaker auxiliary voltage. The method of claim 1,
The opening detection unit 110,
An overvoltage protection unit 111 for preventing overvoltage from being input to an input terminal directly connected to the secondary terminal of the current transformer;
An input voltage attenuation unit 112 for attenuating the voltage at a predetermined rate by adjusting the amplitude of the input voltage input through the input terminal;
A comparator 113 for comparing the input voltage attenuated by the input voltage attenuator 112 with a threshold voltage and outputting a comparison result thereof;
An insulator 114 for turning on the light emitting device according to the comparison result and receiving the optical signal output from the light emitting device, converting the light signal into an electrical signal, and outputting the light signal;
And a short pulse generator (115) for generating a pulse in accordance with the electrical signal output from the insulation unit. The method of claim 1,
The voltage abnormality detection unit,
An overvoltage protection unit 121 which bypasses and protects a circuit when an overvoltage is input to an input terminal directly connected to a secondary terminal of a transformer,
An analog-to-digital converter (hereinafter, referred to as an AC / DC converter) 122 for converting an input voltage input through the input terminal into a digital signal;
A pulse width modulator 123 for modulating a pulse width of an input voltage converted by the AC / DC converter;
An insulator 124 for turning on the light emitting device according to the input voltage subjected to the pulse width modulation, and conducting the light receiving device by turning on the light emitting device to output an electric signal;
And a direct current (DC) converter (125) for converting an electrical signal output from the insulation unit (124) into a direct current signal. The method of claim 1,
The control unit,
And detecting an opening of the secondary terminal of the current transformer to control the relay unit to short-circuit an input terminal of the opening detection unit connected to the secondary terminal of the current transformer detected by the opening and a relay connection terminal to short-circuit. 5. The method of claim 4,
The control unit,
And operating the relay unit to connect the current transformer short-circuit alarm contact point and the relay connection terminal to alarm the opening of the current transformer. The method of claim 1,
The display unit includes:
And a light emitting device for displaying an open detection and a failure of the secondary terminal of the current transformer, a fault relay operation, and a terminal voltage abnormality of each transformer secondary phase and an abnormality of a circuit breaker auxiliary voltage.

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