KR940004223B1 - Earth leakage circuit breaker - Google Patents

Abstract

The relay detects a state of load ground fault in a direct current distribution panel. The device includes a primary coils (LP1,LP2), a secondary coils (LS1,LS2,LS3, LS4,LS5) which generates a corresponding voltages, a pulse generator (300) which generates a low frequency pulse signal, a (-) ground current detector (310) which detects a (-) ground fault in the load, a (+) ground current detector(330) which detects a (+) ground fault in the load, a pulse generation and direct voltage control means (30) which contains an over voltage detector (350), a ground current detecting means (40) which contains ground current detectors (400A-400U), and a load fault signal output control means (50).

Description

DC multiload ground relay

1 shows a front panel of a direct current multiple load ground relay in accordance with the present invention;

2 is a block diagram of a direct current multiple load ground relay shown in FIG.

3 is a detailed circuit diagram of the power supply means, pulse generation and voltage control means of FIG.

4 is a schematic perspective view of a pulsed leak detection current transformer.

FIG. 5 is a detailed circuit diagram of the ground current detecting means and the load failure signal output controlling means of FIG.

* Explanation of symbols for main parts of the drawings

1: (+) DC voltmeter 2: (-) DC voltmeter

3: (+) ground display lamp 4: (-) ground display lamp

5: (+) ground test button 6: (-) ground test button

7: power switch 7A: power lamp

8: (+) ground current setter 9: (-) ground current setter

10: overvoltage trip protection regulator 11: overvoltage trip lamp

12A, 12B: DC power supply output lamp

13: digital clock 14: reset button

15A ~ 15U: Ground Current Sensitivity Regulator on Load Side

L1 ~ L20: Ground detection operation lamp

16: lamp test button 20: power supply means

30: pulse generation and DC voltage control means

40: ground current detection means 40A to 40U: leakage detection current transformer

50: load failure signal output control means

204: power transformer 300: pulse generator

310: (-) ground current detector 330: (+) ground current detector

350: overvoltage detector 400A ~ 400U: ground current detector

500A ~ 500U: Load fault signal output controller

The present invention relates to a DC load grounding relay installed in a DC switchgear for detecting a plurality of load grounds, and particularly, transmits a low frequency pulse in a range that does not affect other equipment on a DC voltage line, The present invention relates to a DC multi-load grounding relay that detects a leaking ground frequency to easily identify a ground state of a load.

In general, DC relay relays installed in DC switchboards to detect the ground condition of the load are operated only when the leakage current of the load flows above the rated value. Since the proper leakage current could not be set, excessive power supply to the load occurred, and the polarity of the ground current could not be classified.

Accordingly, the present invention has been invented in view of the above circumstances, and transmits a low frequency pulse in a range that does not affect a main circuit line that is centrally monitored for a large number of DC loads, and leaks due to grounding at the load side. It detects the grounding frequency and generates an output signal to turn on the light emitting lamp to display the fault load, as well as to easily detect the DC ground line by load, and to set the sensitivity current, polarity classification, and operation time indicator. Its purpose is to provide a DC multiple load grounding relay with built-in functionality that can be used as an efficient replacement for DC line grounding monitoring.

The present invention for achieving this object is a DC multiple load grounding relay installed in the DC switchboard for detecting a plurality of load ground conditions, which is required to generate a low frequency pulse on at least two primary coils and DC power line A first coil for generating a voltage, second and third coils for generating voltages (A-A1) and (B-B1) necessary for detecting the negative (-) and (+) ground currents on the load side, and for overvoltage protection. Power supply means comprising a fourth coil for generating a voltage C-C1 and a fifth coil for generating voltages (+ 12V, -12V) for detecting a fault signal; A pulse generator for providing a low frequency pulse signal in a range that does not affect other devices to the DC power lines P and N by inputting the voltage generated by the first coil, and the voltage generated by the second coil (A-A1). ) Is supplied with power and the (-) ground current detection unit for detecting the (-) ground state on the load side and the voltage (B-B1) generated from the third coil are supplied with power to Pulse generation and direct current including a (+) ground current detector for detecting and an overvoltage detector for protecting the relay from an overvoltage introduced to the input side of the relay by receiving the voltage (C-C1) generated from the fourth coil as a power source. Voltage control means; Ground current detecting means provided on a plurality of DC load-side power lines and including a plurality of ground current detectors for detecting a ground current by converting a low frequency pulse at the ground of the load side; The fault current output control means includes a plurality of fault fault output control means for inputting a ground current detection signal generated by the ground current detection means and outputting a signal indicating a plurality of load ground states, respectively. .

According to the present invention, the pulse generator is composed of a diode for converting the AC signal generated in the first coil in the power supply means to a direct current to apply a low frequency pulse signal of 110HZ ~ 130HZ to the DC line (P, N), (- The ground current detection unit is a diode, a capacitor and a constant voltage IC for converting the AC power (A-A1) generated in the second coil of the power supply means into direct current, and the current sensitivity due to the increased voltage on the DC power supply line (P). A variable resistor for setting a voltage, a comparison amplifier turned on when the voltage caused by the variable resistor increases by comparing the voltage passing through the variable resistor with a reference voltage, and a capacitor and a switch for delaying the output of the comparison amplifier. A delay circuit, a transistor turned on by the delayed signal, a relay and a relay contact for latching to operate a negative ground display lamp when the transistor is operated.

Further, according to the present invention, the (+) ground current detection unit includes a diode, a capacitor and a constant voltage IC for converting the AC power B-B1 generated by the third coil of the power supply means into direct current, and a direct current power supply line (N). A variable resistor that sets the current sensitivity due to the increased voltage of the phase, and a comparison amplifier that is turned on when the voltage caused by the variable resistor increases by comparing the voltage passing through the variable resistor with a reference voltage, and the output of the comparison amplifier. A delay circuit including a capacitor and a switch for delaying, a transistor turned on by the delayed signal, a relay and a relay contact for latching to operate a positive ground display lamp during operation of the transistor. The overvoltage detector sets a diode, a capacitor, and a constant voltage IC for converting the high current power C-C1 generated by the fourth coil of the power supply means into direct current, and an overvoltage trip voltage due to an increased voltage on the direct current power line. A comparison amplifier which is turned on when the voltage caused by the variable resistor increases by comparing the variable resistor, the voltage passing through the variable resistor with the reference voltage, the transistor turned on by the output of the comparison amplifier, and the operation of the transistor. It consists of a relay and a relay contact that latches to operate an overvoltage trip lamp.

In addition, according to the present invention, the plurality of ground current detection unit includes a comparison amplifier for converting the frequency pulse signal detected by each leakage detection current transformer into a digital signal, respectively, the plurality of fault fault signal output control unit, each ground current detection unit A load grounding current sensitivity adjusting resistor for setting a voltage level of a signal output from the signal, a comparison amplifier turned on when the voltage due to the variable increases by comparing the voltage by the resistor with the reference voltage, and the outputs of the comparison amplifiers. It is preferable to configure a delay circuit comprising a capacitor for delaying, a transistor turned on by the delayed signal, a relay for performing a latch operation so as to activate a ground detection operation lamp when the transistor operates, and a relay contact.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 shows a front panel of a DC multi-load ground relay according to the present invention, in which a front panel is provided with a (+) DC voltmeter (1) and a (-) DC voltmeter (2). Only the half voltage is indicated by dividing the display to the (+) and (-) sides, and when these supporting values are summed, the total DC input voltage becomes the same. Normally, the (+) DC voltmeter (1) and the (-) DC voltmeter (2) should indicate almost the same voltage, and it is normal. When grounding, the voltage is biased high or low on one side. Able to know. For example, when the input voltage is 110V, the positive DC voltmeter 1 indicates 75V and the negative DC voltmeter 2 indicates 35V, it can be easily seen that the negative polarity is grounded. Depending on site conditions, there may be voltage variations within about 3V, in which case they are not grounded.

If the DC line is grounded at the (+) polarity side, the red lamp (3) for grounding indicator lights up, and if it is grounded at the (-) polarity side, the green lamp (4) for grounding indicator lights up. Therefore, since the state of the ground is displayed for each polarity by these lamps 3 and 4, monitoring is easy, and at the same time, a fault signal can be sent to the small board and other monitoring circuits through an external contact.

In addition, the ground test buttons 5 and 6 are designed to check the state of the device by arbitrarily flowing a ground current to read the presence or absence of the relay according to the present invention. In this case, the arbitrary ground current is about 20 ~ 30㎃, and during the ground test, the contact is sent to the outside and the alarm is generated on the alarm control panel side. In addition, the power switch 7 is for providing AC input power to the relay shown in FIG. 1 by incorporating a light emitting diode 7A.

On the other hand, the (+) ground current setter 8 and (-) ground current setter 9 can set the ground current sensitivity of the main-stage line of the DC circuit, and the setting range is 4 to 14 ㎃. For example, the ground detection operation lamps L1 to L20 on the load side are lit on several times. When the ground current setters 8 and 9 are adjusted when the load side ground occurs, the ground display lamps 3 or 4 turn on. If the ground indicator lamp 3 or 4 is turned on when the ground current setter 8 or 9 is rotated to the left or right, it can be seen that the ground current at the set position is the ground current value detected at the load side. . Typically, the set current value of the ground current setters 8 and 9 is preferably about 6 to 10 mA.

In addition, when the DC input of the relay exceeds 10% of the rating, the internal power supply is temporarily cut off to protect the relay. The overvoltage trap protection regulator 10 can set the overvoltage. In the overvoltage input, the overvoltage trip lamp 11 is operated. In this case, if the user turns off the power switch 7 and then turns it on again, the relay may be restored to its original state.

On the other hand, the DC power supply output lamps 12A and 12B are for displaying the power supply (+ 12V, -12V) of the relay, and do not turn on when an abnormality occurs. In addition, the digital clock 13 is the same as the normal clock function, but the internal function is completely different, and normally indicates the current time, when the ground signal is detected from the main circuit side, the transmission signal is received to the digital clock 13 input The time is displayed in the stopped state at the time point. Then, after a certain time elapses, when the user presses the reset button 14, the current time is displayed again, and the stopped time will be the time when the failure occurs.

In FIG. 1, the plurality of load side ground current sensitivity regulators 15A to 15U are fine current detection regulators due to ground at the load side, and the detectable range thereof is about 3 to 20 mA. The first glance on the regulator is the 4 ㎃ ground detection range, and the detection range increases with 2, 3, 4, and 5, and the detection range per scale is as follows.

1 scale: about 3.5㎃ ~ 4.5㎃

2 divisions: about 4.0㎃ ~ 6.0㎃

3 divisions: about 5.5㎃ ~ 5.5㎃

4th scale: about 8.0㎃ ~ 12.0㎃

5th scale: about 11.0㎃ ~ 20.0㎃

The ground detection operation lamps L1 to L20 have one of the ground detection operation lamps L1 to L20 turned on when the ground is detected within the DC load side line. If the lamp (3 or 4) is not lit, by adding or subtracting with the main circuit ground current setter (8 or 9), it is possible to check the fault current ground current value. If the ground current indicator (3 or 4) does not turn on even if the ground current setter (8 or 9) is rotated to the left or right, it can be thought of as instantaneous grounding. As described later in FIG. 3, a delay circuit of about 1 second is embedded in the main circuit ground signal contact to avoid frequent operation by momentary grounding on the load side.

In addition, the reset button 14 is a release switch after detecting the fault alarm of the relay, and the ground detection operation lamps L1 to K20 for each load, the main circuit ground display lamps 3 and 4, the digital clock 13, etc. It will return automatically. However, when the main circuit is cut off due to the overvoltage of the DC input, the relay does not return even if the reset switch 14 is operated. In this case, therefore, the input power switch 7 must be turned off and then re-enter. The lamp test button 16 is for checking the operation of the ground detection operation lamps L1 to L20 on the load side. When the lamp test button 16 is pressed, the ground detection operation lamps L1 to L20 simultaneously operate. If any of the ground detection operation lamps L1 to L20 does not operate when the lamp test button 10 is pressed, the user must replace the lamp with a new one. 13A is a button for adjusting the time unit of the digital clock 13, and 13B is a button for adjusting the minute unit.

2 is a block diagram of the DC multiple load grounding relay according to the present invention shown in FIG. 1, the power supply means 20 is for supplying power to the main circuit and the load side circuit. In addition, the pulse generation and the DC voltage control means 30 transmits a low frequency pulse (for example, 110 to 130HZ) in a DC main circuit (P, N) in a range that does not affect other equipment, and when a ground occurs on the load side. It operates the DC voltmeters (1, 2) and ground indicator lamps (3, 4) of FIG. 1 and also cuts off the power supply of the relay to protect the device from overvoltage flowing from the front end of the receiver. In this case, the overvoltage trip lamp 11 is operated.

On the other hand, the ground current detecting means 40 is a low frequency signal sensed by a plurality of pulse-type leakage detection current transformers 40A to 40U, that is, pulse generation and DC voltage control means 30 to the DC line (P, N) The received low frequency signal is transmitted and converted into a digital signal to provide the load failure signal output control means (50). Then, the load failure signal output control means 50 causes the failure portion to be displayed as the ground detection operation lamps L1 to L20. Here, the leak detection current transformer 40A is formed of a hollow cylindrical nickel core as shown in FIG. 4, and a hollow hole 41 is formed, and two DC power lines P are formed in the hole 41. , N passes through, two DC power lines P and N pass through the cylindrical body 42, and screws 43A and 43B are formed in the cylindrical body 42 so that the DC power lines P, At the time of N), a pulse signal is provided to the ground current detecting means 40. In FIG. 2, reference numeral NFB denotes a circuit breaker, 60 denotes a means for controlling the digital clock 13, and the remaining leak detection current transformers 40B to 40N also have the same structure as the current transformer 40A.

FIG. 3 is a detailed circuit diagram of the power supply means 20 and the pulse generation and DC voltage control means 30 shown in FIG. 2. When the user turns on the power switch 7, the AC power supply 220V is a power switch. (7) and the light-emitting diode 7A are turned on via the rectifier diode 70, and are applied to a surge protection circuit composed of the TNR 201, the resistor 202, and the capacitor 203, and a power transformer. 204 is applied to the primary coils LP1 and LP2. The secondary coil LS1 generates an alternating voltage of about 110 V by the primary coil LP1 of the transformer 204, and the power supply of the overvoltage detector 350, which will be described later, in the secondary coil LS2. C, C1) (e.g., 18V).

The primary coil LP2 generates power (A, A1) (for example, 18 V) of the negative ground current detector 310 in its secondary coil LS3, and in another secondary coil LS4. Power supply B and B1 (for example, 18V) of the (+) ground current detector 330 is generated, and an AC voltage of 16V is generated in another secondary coil LS5. The AC voltage generated in the secondary coil LS5 is rectified to DC voltage by the bridge circuit 205 and smoothed by the smoothing capacitors 206 and 207, and then + 12, -12V by the constant voltage ICs 208 and 209. Is generated to supply power to the circuit of FIG.

The power generated from the coil LS1 is half-wave rectified by the half-wave rectifying diodes 301 and 302 constituting the pulse generator 300, and then, through the terminal P and N, the DC line P shown in FIG. 2. , N). At this time, the supplied signal is a low frequency (110 ~ 130HZ) pulse signal may be supplied to the DC line (P, N) so as not to affect other equipment.

The operation of the relay according to the present invention will now be described in detail.

First, when the negative DC line N is grounded, the voltage of the negative DC voltmeter 2 decreases, and the voltage of the positive DC voltmeter 1 increases. In this case, the voltage level of the P-point rises, and this voltage is set through the internal variable resistor 311 and the resistor 312 constituting the (-) ground current detector 310 (9). And a resistor 313 are provided to the non-inverting input terminal of the comparison amplifier 314. The reference voltages of the resistors 315 and 316 and the zener diode 317 are applied to the inverting input terminals of the comparison amplifier 314.

Therefore, when the voltage of the (+) DC voltmeter (1) is higher than the voltage of the (-) DC voltmeter (2), the comparative amplifier 314 outputs a high state signal to the diode 320 through the resistors (318, 319) And a condenser 321 and a switch 322. Here, the switch 322 and the condenser 321 are delay circuits for operating the transistor 323 after about one second when the output of the comparison amplifier 314 is high.

On the other hand, the power generated from the secondary coil LS3 of the power transformer 204 is applied to the terminals A-A1. In this case, the DC voltage rectified by the rectifying diode 324 and the capacitor 325 is a constant voltage. Maintained by the IC 326 at about 12V and applied to the one side input terminal of the light emitting diode 4 for the relay coil X1 and the ground indicator lamp. When the transistor 323 is turned on, a current flows in the relay coil X1. At this time, the relay contact RS1 is connected and the light emitting diode 4 is turned on. It is easy to know that the grounding phenomenon occurred in the negative current line. However, in FIG. 3, when the switch 322 is momentarily grounded by the capacitor 321, the lamp 4 is not driven. In other words, when the output of the comparator 314 becomes high, by frequently turning on the transistor 323 after the charging of the capacitor 321 is completed, it is possible to avoid frequent operation by momentary grounding on the load side. If the ground of the DC line is restored and the output of the comparator 314 becomes low and the transistor 323 is turned off, the relay contact RS1 remains on, so that the negative ground display lamp 4 remains on. When the user presses the reset switch 14, the power supply A-A1 is temporarily turned off and then restored normally. In this case, the relay coil X1 supplied from the constant voltage IC 326 is initialized. That is, it is turned off, and accordingly, the relay contact RS1 is turned off. As the relay contact RS1 is turned off and the transistor 323 is also turned off, the negative ground indicator lamp 4 is turned off so that the relay according to the present invention can be restored to normal.

On the other hand, when the (+) DC line P is grounded, the voltage of the (+) DC voltmeter 2 goes down and the voltage of the (-) DC voltmeter 1 rises. In this case, the voltage level at the N-point rises, and this voltage is passed through the internal variable resistor 331 and the resistor 332 constituting the (+) ground current detector 330. 8) and a resistor 333 are provided to the non-inverting input terminal of the comparative amplifier 334. The reference voltages of the resistors 335 and 336 and the zener diodes 337 are applied to the inverting input terminals of the comparison amplifier 334.

Therefore, when the voltage of the negative DC voltmeter 1 is higher than the voltage of the positive DC voltmeter 2, the comparative amplifier 334 outputs a signal in a high state and the diode 334 through the resistors 338 and 339. And a condenser 341 and a switch 342. Here, the switch 342 and the capacitor 341 are delay circuits for operating the transistor 343 after about one second when the output of the comparison amplifier 334 is high.

On the other hand, the power generated from the secondary coil LS4 of the power transformer 204 is applied to the terminal B-B1, in which case the DC voltage rectified by the rectifying diode 344 and the capacitor 345 is The voltage is maintained at about 12V by the constant voltage IC 346 and applied to the one side input terminal of the light emitting diode 3 for the relay coil X2 and the ground indicator lamp. When the transistor 343 is turned on, a current flows in the relay coil X2. At this time, the light emitting diode 3 is turned on at the same time as the relay contact RS2 is connected. It is easy to know that a ground phenomenon has occurred in the positive current line. By the way, in FIG. 3, when there is instantaneous grounding by the switch 342 and the condenser 341, the lamp 3 is not driven. In other words, when the output of the comparator 334 becomes high, first, the transistor 343 is turned on after charging of the capacitor 341 is completed, and then the transistor 343 is turned on after the loading of the load is completed, and the instantaneous ground on the load side is turned on. Frequent operation by the user can be avoided. If the ground of the (+) DC line is restored and the output of the comparator 334 is turned low and the transistor 343 is turned off, the relay contact RS2 remains on, so that the (+) ground display lamp 3 When the user presses the reset button 14, the power supply B-B1 is temporarily turned off and then restored normally. In this case, the relay coil X2 supplied from the constant voltage IC 346 is maintained. ) Becomes an initial state, i.e., an off state, whereby the relay contact RS2 is turned off. As the relay contact RS2 is turned off and the transistor 343 is also turned off, the (+) ground display lamp 3 is turned off so that the relay according to the present invention can be restored to normal.

To test the operating status of the ground indicator lamps (3,4), press the ground test buttons (5,6). If you want to test the operating status of the (+) ground indicator lamp (3), test the ground. Press button (5). When the ground test button 5 is pressed, the voltage level of the (+) DC voltmeter 1 decreases, and the voltage level of the (-) DC voltmeter 2 rises, in which case the comparator 334 as described above. The transistor 343 is turned on to operate the relay coil X2, and the relay contact RS2 is turned on so that the light emitting diode 3 can be turned on. If is not lit, the light emitting diode 3 is broken and must be replaced with a new one. When the reset button 14 is pressed, the operation of the light emitting diodes 3 is stopped to test the operation of the lamp. In addition, when the operation state of the lamp 4 is tested, the negative ground test button 6 is pressed. In this case, the comparator 314 operates, and the relay coil 323 is driven by the output of the transistor 323. X1) and the relay contact RS1 are turned on so that the lamp 4 can be tested as described above.

However, when an overvoltage occurs in the DC input power line, the voltage at the Q-point of FIG. 3 is increased, and the voltage is increased by the resistor 351 constituting the overvoltage detector 350 and the resistor 10 for overvoltage trip protection adjustment. And a non-inverting input terminal of the comparative amplifier 353 through the resistor 352. The reference voltages of the resistors 354 and 355 and the zener diode 356 are applied to the inverting input terminal of the comparison amplifier 353. Therefore, the reference voltage of the comparison amplifier 353 is preferably set to about 10% higher than the DC input voltage. When the DC input voltage is higher than the reference voltage, the comparison amplifier 353 outputs a signal in a high state so that the resistance ( Via 357, 358, transistor 359 can be turned on immediately.

On the other hand, the power generated from the secondary coil LS2 of the power transformer 204 is applied to the terminal C-C1, in which case the DC voltage rectified by the rectifying diode 360 and the capacitor 361 is a constant voltage. It is maintained at about 12V by the IC 362 and applied to the one side input terminal of the relay coil X3 and the overvoltage light emitting diode 11. When the transistor 359 is turned on, a current flows in the relay coil X3, and at this time, the light emitting diode 11 is turned on at the same time as the relay contact RS3 is connected, so that the user may turn on the overvoltage display lamp 11. It can be easily seen that an overvoltage has occurred. In addition, a buzzer 363 may be provided to notify the occurrence of overvoltage. Here, when the relay coil X3 is operated, the relay contact RS3 is kept on, so that the lamp 11 is continuously lit, while the overvoltage control contact RS3 in the power supply means 20 is turned off. When the contact RS3 is turned off, the primary coil LP2 of the power transformer 204 is opened so that a voltage signal is not output from the secondary coils LS3, LS4, and LS5 of the power transformer 204. 310 and the (+) ground current detection unit 330 and the circuit shown in FIG. 5 do not operate, but since the primary coil LP1 of the source transformer 204 is live, the secondary coils LS1 and LS2 Since the voltage is continuously generated, the low frequency pulse signal for the DC lines N and P continues to be supplied, and since the power C-C1 is continuously applied, the overvoltage detector 350 continues to operate. However, even if the DC input voltage returns normally, the lamp 11 shown in FIG. 3 does not turn off. Therefore, even if the reset button 14 is pressed, the overvoltage detection unit 350 does not recover. In this case, when the power switch 7 is turned off and then on again, the power to the relay coil X3 is temporarily turned off. Since the relay contact RS3 is turned off, the operation of the light emitting diode 11 is stopped. Accordingly, the contact RS3 is closed so that the relay of FIG. 3 can be returned to its normal state.

By the way, in FIG. 3, when the relay coil X1 or X2 is operated, the digital clock control means 60 shown in FIG. 2 is the digital clock at the time when the relay coil X1 or X2 is operated. By causing (13) to stop, the time at which the ground is generated is displayed. As described above, when the reset button 14 is pressed, the operations of the (-) DC ground detector 310 and the (+) DC ground detector 330 are stopped, and the digital clock control means 60 of FIG. The digital clock 13 then displays the current time.

FIG. 5 is a detailed circuit diagram of the ground current detecting means 40 and the fault signal output control means 50 shown in FIG. 2. In FIG. 5, reference numerals 40A to 40U denote leak detection shown in FIG. The current transformers 400A to 400U constitute a part of the ground current detection means 40 to display the ground current detection units for detecting signals of the leak detection current transformers 40A to 40U installed on each load side. Reference numerals 500A to 500U denote circuits for operating the ground state of the load as the ground detection operation lamps L1 to L20. By the way, the ground current detectors 44A to 400U have the same configuration, and the load fault signal output control units 500A to 500U also have the same configuration, and like reference numerals denote the same components.

If the leakage detection current transformer 40A of the plurality of leakage detection current transformers 40A to 40U is operated (that is, when a ground signal is detected), the low frequency pulse signal loaded on the DC lines N and P is the leakage detection current transformer 40A. In this case, the leakage detection current transformer 40A provides a frequency voltage signal to the comparison amplifier 405A via the coupling capacitor 410A, the resistors 402A, 403A, and the capacitor 404A. At this time, the comparative amplifier 405A outputs a high state signal to generate a DC voltage through the resistor 406A, the diode 407A, and the capacitor 408A.

The generated voltage is provided to the variable resistor 15A via the resistor 510A and the internal variable resistor 502A in the fault signal output control unit 500A. At this time, the voltage level adjusted by the variable resistor 15A is provided to the non-inverting input terminal of the comparison amplifier 504A through the resistor 503A. On the other hand, the reference voltages of the resistors 505A and 506A and the zener diode 507A are applied to the inverting input terminals of the comparison amplifier 504A. In this case, the comparison amplifier 504A outputs a signal in a high state so that the resistance 508A is applied. Is applied to the base of the transistor 510A via 509A. Here, the capacitor 511A at the base of the transistor 510A is for delaying the output of the comparator 504A to a certain degree (about 0.5 seconds), which is to prevent the case of returning to the original state after the momentary grounding of the load side. will be. If the high state output of the comparator 504A is generated for a long time, the transistor 510A is turned on. In this case, the relay coil XA is operated.

When the relay coil XA is activated, the relay contact RXA is turned on. As the transistor 510A and the relay contact RXA are turned on, the power supply (+ 12V) is grounded through the reset button 14 which is turned on. The ground detection operation lamp L1 is turned on because the operation lamp is bypassed to ground through the collector-emitter of the light emitting diode L1, the resistor 512A, the diode 513A, the relay contact RXA, and the transistor 510A. Done.

If the sensitivity current by the ground current sensitivity adjustment variable resistor 15A on the first load side is set to 5 mA, the sensitivity current by the (+) or (-) ground current setting resistor 8 or 9 is 10. If it is set to ㎃, when a ground current of 5 에 flows to the (+) side of the first load, the ground alarm ground detection operation lamp L1 turns on, but the (+) ground detector 330 shown in FIG. Ground display lamp (3) does not light up. This is because the positive ground current setter 8 on the main circuit side is not detected at the position of 10 mA. In this case, if you turn the (+) ground current setter 8 slowly counterclockwise, the ground indicator lamp 3 turns on, so that the user can know that the ground current at the load side is grounded at approximately 5 ㎃. do.

On the other hand, when the ground of the load is restored, the output of the comparative amplifier 405A is turned low, so that the comparative amplifier 504A is also turned down so that the transistor 510A is turned off, but the relay contact RXA is turned on. Since the light emitting diode L1 is kept in the lit state. In this case, when the user presses and releases the reset button 14, the power supply (+ 12V, -12V) is turned off and then turned on again, so that the relay coil XA is reset, the relay contact RXA is turned off, and the light emitting diode L1 is turned off. At the same time, the lamp 3 or 4 shown in FIG. 3 is also turned off, so that the relay of the present invention is reset to an initial state so that the ground of the load is continuously monitored.

When the user presses the lamp test button 16, the power supply (+ 12V) is connected to the reset button 14, the light emitting diode L1, and the resistor 512A regardless of the relay coil XA and the relay contact RXA. Bypassing to ground via the diode 514A and the lamp test button 16, the light emitting diode L1 is turned on so that the user can check whether there is an abnormality of the lamp L1.

As shown in the lower part of FIG. 5, the circuit also operates in the same manner as in the case of the first load, as described above.

The present invention operates as described above and transmits a low frequency pulse in a range that does not affect other devices on the main circuit line, and fixes the ground frequency leaked by ground at the load side by lighting an lamp with an output signal received from a special digital conversion circuit. It displays the part, and sets the ground-sensitivity current for each polarity and protects the power supply of the relay when the rated voltage exceeds the range of about 10% to protect it from overvoltage flowing from the front end of the receiver. It is designed to cope with surge invading from the outside by adding surge protection circuit, and if the signal is detected by the ground of load side and the relay is operated, the instruction of the hour meter is automatically stopped by the memory. If you return after troubleshooting, The built-in display function makes it easy to read the down time.

Although the present invention has been described with reference to the accompanying drawings, the present invention is not limited thereto, and many changes and modifications may be made without departing from the scope of the following claims. For example, as shown in FIG. 1, 20 loads are shown, but the number of loads may be reduced to 10 or extended to 30 or more. In this case, the load side of FIG. This is possible by expanding a plurality of circuits.

Claims (7)

A DC multiple load grounding relay installed in a DC switchgear for detecting a plurality of load ground states; At least two primary coils LP1 and LP2, a secondary coil LS1 for generating a voltage required to generate a low frequency pulse on a DC power line, and a negative (+) ground current on the load side. Secondary coils LS3 and LS4 for generating voltages A-A1 and B-B1, secondary coils LS2 for generating a voltage C-C1 for overvoltage protection, and for detecting a fault signal A power supply means 20 comprising two coils LS5 for generating voltages (+ 12V, -12V); The pulse generator 300 and the voltage for providing a low frequency pulse signal in a range that does not affect other devices to the DC power supply lines P and N by inputting the voltage generated by the secondary coil LS1. (-) Ground current detection unit 310 for detecting (-) grounding state of load side by receiving (A-A1) as a power source and (+) A ground current detector 330 for detecting ground current and an overvoltage detector 350 for protecting the relay from an overvoltage introduced to the input side of the relay by receiving the voltage C-C1 as a power source; Pulse generation and direct voltage control means (30); Ground current detecting means (40) provided on a plurality of DC load-side power lines and including a plurality of ground current detection units (400A-400U) for converting the low frequency pulses into digital signals to detect ground currents when the load side is grounded; ; Load fault including a plurality of load fault signal output control unit (500A ~ 500U) for inputting the ground current detection signal generated by the contact current detection means 40 to output a signal indicating a plurality of load ground state, respectively DC multiple load grounding relay, characterized in that consisting of signal output control means (50). The method of claim 1, wherein the pulse generator 300 converts the AC signal generated by the secondary coil LS1 in the power supply means 20 to direct current to 110HZ to the direct current line (P, N). A DC multiple load grounding relay comprising a diode (301, 302) for applying a low frequency pulse signal of 120 Hz. The diode (324) of claim 1, wherein the (-) ground current detector 310 converts AC power A-A1 generated by the secondary coil LS3 of the power supply means 20 into direct current. ), A capacitor 325 and a constant voltage IC 326, a variable resistor 9 for setting the current sensitivity due to the increased voltage on the DC power supply line P, a voltage passing through the variable resistor and a reference voltage. In comparison, a delay circuit including a comparison amplifier 314 turned on when the voltage by the variable resistor 9 increases, and a capacitor 321 and a switch 322 for delaying the output of the comparison amplifier 314. And a transistor 323 turned on by the delayed signal, a relay X1 and a relay contact RS1 for latching to operate the negative ground indicator lamp 4 when the transistor 323 is operated. DC multiple load grounding relay, characterized in that the configuration. The method of claim 1, wherein the (+) ground current detector 330 is a diode for converting the AC power (B-B1) generated in the secondary coil (LS4) of the power supply means 20 to direct current ( 344, the capacitor 345 and the constant voltage IC 346, the variable resistor 8 for setting the current sensitivity by the increased voltage on the DC power supply line (N), the voltage passing through the variable resistor and the reference voltage In comparison, a delay circuit including a comparative amplifier 334 which is turned on when the voltage by the variable resistor 8 increases, and a capacitor 341 and a switch 342 for delaying the output of the comparison amplifier 334. And a transistor 343 turned on by the delayed signal, a relay X2 and a relay contact RS2 which perform a latching operation to operate a positive ground indication lamp 3 when the transistor 343 is operated. DC multi-load ground relay, characterized in that consisting of). The method of claim 1, wherein the over-voltage detection unit 350 is a diode 360, a capacitor for converting the AC power (C-C1) generated in the secondary coil (LS2) of the power supply means 20 to direct current 361 and a constant voltage IC 362, a variable resistor 10 for setting an overvoltage trip voltage due to an increased voltage on the DC power line, and a variable resistor 10 by comparing the voltage passing through the variable resistor with a reference voltage. The comparison amplifier 353 turned on when the voltage of the transistor increases), the transistor 359 turned on by the output of the comparison amplifier 353, and the overvoltage trip lamp 11 when the transistor 359 is operated. DC multi-load ground relay, characterized in that consisting of a relay (X3) and a relay contact (RS3) for the latch operation to operate. The plurality of ground current detectors 400A to 400U respectively include comparative amplifiers 405A to 405U for converting the frequency pulse signals detected by the leak detection current transformers 40A to 40U into digital signals. DC multi-load grounding relay characterized in that the. The load ground current sensitivity adjusting resistor (15A) of claim 1, wherein the plurality of load fault signal output controllers (500A through 500U) set voltage levels of signals output from the respective ground current detectors (400A through 400U). 15U) and the comparison amplifiers 412A to 412U that are turned on when the voltage due to the variable resistors 15A to 15U increases by comparing the voltage by the resistor with the reference voltage, and the outputs of the comparison amplifiers 412A to 412U. A delay circuit comprising capacitors 419A to 419U for delaying the circuit, transistors 418A to 418U turned on by the delayed signal, and ground detection operation lamps L1 to L20 during operation of the transistors 418A to 418U. DC multi-load ground relay, characterized in that each consisting of a relay (XA ~ XU) and a relay contact (RXA ~ RXU) that performs a latch operation to operate.