JP6932964B2 - DC power supply circuit disconnection discriminator and wiring discriminator - Google Patents

Description

The present invention relates to a disconnection discriminating device and a wiring discriminating device for a DC power supply circuit that discriminates a disconnection and wiring of a DC power supply circuit that supplies DC power to a control circuit for operating an electric device of an electric place.

Electric stations such as substations and switchyards are provided with a DC power supply circuit that supplies DC power to a control circuit for operating electric devices such as circuit breakers and disconnectors. A plurality of DC power supply circuits are drawn from the DC bus to which the DC power supply device is connected, and further branch off from the DC power supply circuit to supply DC power to a control circuit which is a large number of DC loads.

In such a DC power supply circuit, a DC ground relay (64D) for detecting a ground fault in the DC power supply circuit is installed. The DC ground relay is provided in a voltage dividing circuit in which the positive and negative electrodes of the DC bus of the DC power supply circuit are divided by resistance, and the middle point of the voltage dividing circuit is grounded via a resistor. The DC ground relay operates when the voltage of the voltage divider circuit is out of balance.

A DC ground relay can detect a ground fault in the DC power supply circuit, but a DC ground relay cannot detect a disconnection in the DC power supply circuit. For example, if the DC power supply circuit downstream of the output contact of the protective relay is disconnected, the trip coil and closing coil of the circuit breaker cannot be operated even if the protective relay operates, so the output of the protective relay It is required to determine whether or not the DC power supply circuit downstream of the contact is broken.

In addition, the wiring of the DC power supply circuit may be changed due to construction work at an electric station, etc. In that case, if there is a connection error in the DC power supply circuit, the DC power supply may be hindered or a facility accident may occur. Alternatively, it may lead to a serious situation such as wiring damage. Therefore, it is necessary to check whether or not the connection of the wire whose wiring has been changed is correctly wired. To check the wire connection, perform wire insulation resistance measurement, conduction resistance measurement, low voltage application measurement, operation test, etc. with the electrical equipment (main circuit) and control circuit of the electric station stopped (power failure). Is inspected to see if it is wired correctly. It is also conceivable to measure the voltage of the electric wire while the operation is continued (live line state).

Here, when a DC ground fault relay detects a ground fault in the DC power supply circuit, the ground fault current is generated by opening and closing the relay contact with the flicker relay while the operation is continued (live line state). Is converted into a rectangular wave pulsating current and output, and the rectangular wave pulsating current is detected by a detector to improve the detection accuracy of the search for a DC grounding point (see, for example, Patent Document 1).

Special Fair 5-35384 Gazette

However, in order to determine whether or not the DC power supply circuit downstream of the output contact of the protection relay is broken, the protection relay is operated with the main circuit and control circuit of the electric station stopped, and the trip coil of the circuit breaker is turned on. Since it is determined whether or not the coil operates, a power failure occurs in the main circuit, which hinders the power supply to the consumer. Further, when checking whether or not the connection of the changed electric wire is correctly wired, the main circuit and the control circuit of the electric station are stopped, so that a power failure occurs in the main circuit. Therefore, it is required to determine whether or not the DC power supply circuit is broken and whether or not the wiring is connected in a state where the main circuit is continuously operated (live line state).

In order to determine whether the DC power supply circuit is broken or not and whether the wiring is connected or not in the live state, measure the voltage at both ends of the electric wire or apply an exploration current that does not operate the electrical equipment. It is conceivable to discriminate by detection. The exploration current is set so that the electrical equipment does not operate in order to prevent unnecessary operation of the electrical equipment.

In Patent Document 1, the ground fault current is converted into a rectangular pulsating current by opening and closing the relay contact with a flicker relay in a state where the operation is continued (live wire state), and the rectangular pulsating current is output. By detecting the flow with a detector, the detection accuracy of the DC grounding point search is improved, but the ground fault current is converted into a rectangular wave pulsating current and output to search for the DC grounding point. Therefore, it does not operate unless a ground fault current is generated. Therefore, it cannot be applied as it is to the one for determining the presence or absence of disconnection of the DC power supply circuit and the quality of wiring connection in the live wire state.

In addition, regarding the judgment of the quality of wiring, a wraparound voltage may be generated via a branch of the control circuit or an auxiliary relay coil in the control circuit, so it is possible to judge the quality of wiring only by measuring the voltage at both ends of the wire. It may not be possible. This is because even if the wiring is erroneously wired, a wraparound voltage may be generated at the other end of both ends of the electric wire via the other wiring.

An object of the present invention is to provide a DC power supply circuit disconnection discrimination device and a wiring discrimination device capable of discriminating the presence or absence of a disconnection of a DC power supply circuit and determining the quality of wiring connection in a live wire state.

The disconnection discriminating device for the DC power supply circuit according to the invention of claim 1 is the positive and negative sides of the DC bus of the DC power supply circuit that supplies DC power from the DC power supply device to the control circuit for operating the electric equipment of the electric station. A DC ground fault relay that operates when the voltage balance of the voltage splitting circuit is lost and detects a ground fault failure of the DC power supply circuit is provided between the voltage dividing circuit and the voltage dividing circuit. It is a disconnection discriminating device for the DC power supply circuit that inspects the presence or absence of disconnection of the DC power supply circuit that it has; A connection terminal for connecting to an electric wire located on the side; a grounding device for grounding the connection point of the connection terminal to the ground; forcibly grounding the connection point of the connection terminal to the grounding device at the time of inspection. The grounding unit is connected to the connection terminal, and the connection terminal is forcibly grounded to the grounding device at the time of inspection, and a DC exploration current from the DC power supply device is applied to the connection terminal. A forced ground switch for supplying from the connection point to the circuit to be inspected, a current limiting resistor connected in series to the forced ground switch to limit the exploration current, and a voltage for detecting the ground voltage at the connection point of the connection terminal. The detection unit, the current detection unit that detects the exploration current flowing through the connection point of the connection terminal, and the voltage / current determination unit that determines the quality of the voltage value and the current value detected by the voltage detection unit and the current detection unit. It is characterized in that it checks for disconnection of the DC power supply circuit based on the determination result of the voltage / current determination unit of the grounding unit.

In the invention of claim 1, the grounding unit is connected in series with the current limiting resistor, and the magnitude of the exploration current is a predetermined constant value. It is characterized by having a current limiting circuit that adjusts to.

In the invention of claim 1 or the invention of claim 2, the grounding unit is the voltage value detected by the voltage detection unit and the current detection unit. It is characterized by including a message output unit that outputs a message of the current value detected in the above and the determination result of the voltage / current determination unit.

In the invention of any one of claims 1 to 3, the grounding unit is a lamp that displays the determination result of the voltage / current determination unit. It is characterized by having a display unit.

The wiring discriminating device for the DC power supply circuit according to the invention of claim 5 is a positive and negative electrode of the DC bus of the DC power supply circuit that supplies DC power from the DC power supply device to the control circuit for operating the electric equipment of the electric station. A DC ground fault relay that operates when the voltage balance of the voltage splitting circuit is lost and detects a ground fault failure of the DC power supply circuit is provided between the voltage dividing circuit and the voltage dividing circuit. It is a wiring discriminator for the DC power supply circuit that checks the quality of the wiring of the DC power supply circuit that it has; at one end of the circuit to be inspected that checks the quality of the wiring of the DC power supply circuit at the time of inspection. A first unit to be connected; a second unit connected to the other end of the inspection target circuit at the time of inspection; the first unit is the DC power supply device as one end of the inspection target circuit. A connection terminal for connecting to an electric current located outside the end on the opposite side of the device, and a grounding device for grounding the connection point of the connection terminal to the ground; A grounding unit according to any one of claims 2 to 4 for forcibly grounding the grounding device; the second unit is outside the end on the DC power supply side as the other end of the circuit to be inspected. A high-sensitivity DC current clamp meter that detects the DC exploration current supplied from the DC power supply device after being clamped to the electric wire located in the above and adjusting the zero point, and the exploration current detected by the high-sensitivity DC current clamp meter. It has an intermediate unit having a current determination unit for determining the quality of the current value of the DC power supply circuit; based on the determination results of the voltage / current determination unit of the ground unit and the current determination unit of the intermediate unit. It is characterized by checking the quality of wiring connections.

The wiring discriminating device for the DC power supply circuit according to the invention of claim 6 is the invention of claim 5, wherein the intermediate unit is a current value detected by the high-sensitivity DC current clamp meter , and a determination result of the current determination unit. It is characterized by having a message output unit for outputting a message.

In the invention of claim 5 or 6, the intermediate unit includes a lamp display unit for displaying the determination result of the current determination unit. It is characterized by that.

According to the invention of claim 1, when inspecting for disconnection, the connection terminal is connected to an electric current located on the DC power supply side of the circuit to be inspected, and the forced grounding switch of the grounding unit is turned on to connect the connection terminals. The location is grounded to the ground via a grounding device, the DC exploration current limited by the current limiting resistance is supplied from the DC power supply device to the circuit to be inspected, and the voltage / current determination unit of the grounding unit is detected by the voltage detection unit. The quality of the exploration current flowing through the connection point detected by the ground voltage and current detection unit of the connection point is judged, and the disconnection of the DC power supply circuit is determined based on the judgment result of the voltage / current judgment unit. Even if it is, the disconnection of the DC power supply circuit can be determined.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, a current limiting circuit for adjusting the magnitude of the DC exploration current limited by the current limiting resistor so as to be a predetermined constant value is provided. Therefore, the exploration current becomes a constant value. Therefore, the current detected by the current detection unit can be stably detected.

According to the invention of claim 3, in addition to the effect of the invention of claim 1 or the invention of claim 2, the message output unit includes the voltage value of the connection portion of the connection terminal of the inspection target circuit and the connection terminal of the inspection target circuit. Since the current value of the exploration current flowing through the connection point and the judgment result of the voltage / current determination unit are output as a message, the quality result of the voltage value and the current value of the connection point of the connection terminal of the circuit to be inspected can be easily grasped.

According to the invention of claim 4, in addition to the effect of the invention of any one of claims 1 to 3, the determination result of the voltage / current determination unit is displayed on the lamp display unit, so that the connection terminal of the circuit to be inspected is displayed. It is possible to visually grasp the quality result of the voltage value and the current value of the connection point of.

According to the invention of claim 5, when checking the quality of the wiring connection, the grounding unit is connected to the electric wire located on the outside opposite side of the DC power supply device of the circuit to be inspected, and the current limiting resistance is applied from the DC power supply device. The limited current DC exploration current is supplied to the circuit to be inspected, and the voltage / current determination unit of the grounding unit determines the quality of the ground voltage at the connection point and the exploration current flowing through the connection point, while the high-sensitivity DC current clamp meter. Is clamped to the electric wire located outside the DC power supply side of the inspection target circuit of the DC power supply circuit, and the current judgment part of the intermediate unit judges the quality of the current value of the probe current detected by the high-sensitivity DC current clamp meter. Then, based on the judgment results of the voltage / current judgment unit of the grounding unit and the current judgment unit of the intermediate unit, the quality of the connection of the wiring of the DC power supply circuit is determined. The quality of the connection can be determined.

According to the invention of claim 6, in addition to the effect of the invention of claim 5, the message output unit of the intermediate unit outputs a message of the current value on the DC power supply side of the circuit to be inspected and the determination result of the current determination unit. , The quality result of the current value on the DC power supply side of the circuit to be inspected can be easily grasped.

The DC power supply circuit wiring discriminating device according to the invention of claim 7 has the effect of the invention of claim 5 or 6, and the lamp display unit of the intermediate unit has a current value on the DC power supply side of the circuit to be inspected. Since the judgment result of is displayed, it is possible to visually grasp the quality result of the current value on the DC power supply side of the circuit to be inspected.

The block diagram which shows an example of the disconnection discriminating apparatus of the DC power supply circuit which concerns on 1st Embodiment of this invention. FIG. 5 is an explanatory diagram of an exploration current path that flows when the forced grounding switch of the grounding unit of the disconnection discriminating device of the DC power supply circuit according to the first embodiment of the present invention shown in FIG. 1 is turned on. It is a block diagram which shows another example of the grounding unit of the disconnection determination device of the DC power supply circuit which concerns on 1st Embodiment of this invention. The graph which shows the voltage-current characteristic of the current limiting circuit of the grounding unit shown in FIG. The block diagram which shows an example of the wiring discriminating device of the DC power supply circuit which concerns on 2nd Embodiment of this invention. The block diagram which shows an example of the 2nd unit of the wiring discriminating device of the DC power supply circuit which concerns on 2nd Embodiment of this invention. The explanatory view of the exploration current path which flows when the forced grounding switch of a grounding unit is turned on when the wiring of the circuit to be inspected is normal in the 2nd Embodiment of this invention. FIG. 5 is an explanatory diagram of an example of an exploration current path that flows when a wiring discriminating device is connected to a circuit to be inspected and the forced grounding switch of the grounding unit is turned on when the wiring is incorrect in the second embodiment of the present invention. FIG. 8 is an explanatory diagram of an example of an exploration current path that flows when a wiring discriminating device is connected to another circuit to be inspected and the forced grounding switch of the grounding unit is turned on in the case of incorrect wiring shown in FIG. FIG. 5 is an explanatory diagram of an example of an exploration current path that flows when a wiring discriminating device is connected to a circuit to be inspected and the forced grounding switch of the grounding unit is turned on when another miswiring is performed in the second embodiment of the present invention. FIG. 10 is an explanatory diagram of an example of an exploration current path that flows when a wiring discriminating device is connected to another circuit to be inspected and the forced grounding switch of the grounding unit is turned on when the wiring is incorrect as shown in FIG. The explanatory view of the exploration current path which flows when the forced grounding switch of a grounding unit is turned on when the wiring of the circuit to be inspected of a negative electrode property is normal in 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a configuration diagram showing an example of a disconnection determination device for a DC power supply circuit according to the first embodiment of the present invention, and shows a case where the presence or absence of disconnection of the DC power supply circuit downstream of the output contact of the protective relay is determined. Shown.

In the DC circuit of an electric station, DC power is supplied from the DC bus 12 to which the DC power supply device 11 is connected to the control circuit 15 via the switch 34 and the switchboard 13 via the DC power supply circuit 14. The DC bus 12 of the DC circuit is composed of a positive electrode bus 12P and a negative electrode bus 12N, the positive electrode bus 12P is connected to the positive DC power supply circuit 14P via the switch 34P and the switchboard 13, and the negative electrode bus 12N is the switch. It is connected to the negative electrode DC power supply circuit 14N via 34N and the switchboard 13.

Between the positive electrode bus 12P of the DC bus 12 and the negative electrode bus 12N (between the positive electrode and the negative electrode), a voltage dividing circuit 16 is installed in which the positive electrode and the negative electrode are subjected to resistance voltage division and the voltage dividing middle point is resistance grounded. The voltage dividing circuit 16 constitutes an element of the DC ground fault relay 17 for detecting the ground fault of the DC circuit, and the DC ground fault relay 17 operates when the voltage of the voltage dividing circuit 16 is out of balance.

The switchboard 13 houses a monitoring control device that monitors and controls the control circuit 15, and the control circuit 15 houses an operating device for operating various electric devices in an electric place. FIG. 1 shows a case where a protective relay 18 and its output contact 19 are installed on the switchboard 13, and a circuit breaker operating device 20 operated by the output contact 19 of the protective relay 18 is housed in the control circuit 15. There is. The circuit breaker operating device 20 includes a trip coil that opens the circuit breaker main contact, a closing coil that closes the circuit breaker main contact, and the like, but only the trip coil 21 is shown in FIG.

Here, in determining whether or not the DC power supply circuit 14 downstream of the output contact 19 of the protective relay 18 is disconnected, the disconnection determination device of the DC power supply circuit according to the first embodiment of the present invention is the DC power supply circuit 14. Connected to. The disconnection determination device includes a connection terminal 22, a grounding unit 23, and a grounding device 24.

The connection terminal 22 is a terminal connected to an electric wire located on the DC power supply device 11 side of the circuit to be inspected for checking for disconnection in the DC power supply circuit. In FIG. 1, since the DC power supply circuit 14 downstream of the output contact 19 of the protective relay 18 is the circuit to be inspected, the connection terminal 22 is the DC power supply 11 side of the electric wires downstream of the output contact 19 of the protective relay 18. That is, it is connected to the immediate downstream of the output contact 19.

The grounding unit 23 includes a forced grounding switch 25, a current limiting resistor 26, a voltage detection unit 27, a current detection unit 28, a voltage / current determination unit 29, and an output unit 30, and has a voltage value and a current value at the connection point of the connection terminal 22. The quality of the above is determined and output to the output unit 30.

The forced grounding switch 25 and the current limiting resistor 26 of the grounding unit 23 are connected in series with the connection terminal 22, and when the forced grounding switch 25 is turned on, the connection terminal 22 is grounded to the ground via the grounding device 24. FIG. 1 shows a case where the forced grounding switch 25 is off.

The current limiting resistor 26 limits the exploration current, and limits the exploration current to a current such that the trip coil of the circuit breaker operating device 20 does not operate. This prevents the trip coil from operating unnecessarily due to the exploration current when determining the presence or absence of disconnection.

The voltage detection unit 27 detects the voltage to ground at the connection point of the connection terminal 22, and inputs the voltage to ground of the voltage detection resistor internally connected in parallel to the series circuit of the forced ground switch 25 and the current limiting resistor 26. It is converted into a signal that can be processed by the voltage / current determination unit 29 and output to the voltage / current determination unit 29. Since one end of the voltage detection resistor is grounded to the grounding device 24, the voltage of this voltage detection resistor is detected as the ground voltage at the connection point of the connection terminal 22 regardless of whether the forced grounding switch 25 is turned on or off.

On the other hand, the current detection unit 28 detects the exploration current flowing through the connection point of the connection terminal 22, and a part of the current limiting resistance is used as the current detection resistance, and the voltage to ground of the current detection resistance is measured. The current flowing through the current limiting resistor 26 is input as a search current, converted into a signal that can be processed by the voltage / current determination unit 29, and output to the voltage / current determination unit 29. When the forced ground switch 25 is off, the exploration current flowing through the current limiting resistor 26 is zero.

The voltage / current determination unit 29 determines the quality of the voltage value and the current value detected by the voltage detection unit 27 and the current detection unit 28. Judge the quality of the exploration current flowing through. The voltage to ground at the connection point of the connection terminal 22 should be a value around 1/2 of the DC power supply voltage E (voltage E between the positive electrode and the negative electrode) of the DC power supply device 11. The voltage reference value for pass / fail judgment is set to a value of about 1/2 of the DC power supply voltage E because the voltage dividing midpoint of the voltage dividing circuit 16 is grounded when the forced grounding switch 25 is turned on. This is because the voltage to ground at the connection point of the connection terminal 22 is the voltage between the positive or negative voltage of the DC power supply device 11 and the voltage dividing midpoint (grounding point) of the voltage dividing circuit 16.

Further, since the exploration current flowing through the connection point of the connection terminal 22 is determined by the ground voltage of the connection point of the connection terminal 22 and the size of the current limiting resistor 26, the current reference value limited by the current limiting resistor 26 is obtained in advance. It is acceptable if the exploration current flowing through the connection point of the connection terminal 22 has a magnitude of the current reference value. The quality of the voltage to ground at the connection point of the connection terminal 22 and the exploration current flowing through the connection point of the connection terminal 22 is determined by giving a range to the voltage reference value and the current reference value in consideration of a predetermined error range.

The quality determination result of the voltage / current determination unit 29 is output to the output unit 30. The output unit 30 has a message output unit 31 and a lamp display unit 32. In addition to the quality determination result of the voltage / current determination unit 29, the message output unit 31 also displays and outputs the voltage value of the connection portion of the connection terminal 22 of the circuit to be inspected and the current value of the exploration current flowing through the connection portion of the connection terminal 22. .. For example, when the determination result is good, the characters are displayed as good or OK, and when the judgment result is bad, the characters are displayed as no or NO. The voltage value and current value are displayed numerically. As a result, it is possible to easily grasp the quality result of the voltage value and the current value at the connection point of the connection terminal of the circuit to be inspected. Further, the lamp display unit 32 displays the determination result of the voltage / current determination unit 29 as a lamp. For example, when the judgment result is good, it is displayed in green, and when it is not, it is displayed in red. As a result, it is possible to visually grasp the quality result of the voltage value and the current value at the connection point of the connection terminal of the circuit to be inspected.

FIG. 2 is an explanatory diagram of the path of the exploration current that flows when the forced grounding switch of the grounding unit of the disconnection determining device of the DC power supply circuit according to the first embodiment of the present invention shown in FIG. 1 is turned on. As shown in FIG. 2, when the forced grounding switch 25 of the grounding unit 23 is turned on, the forced grounding switch 25 is connected to the connection terminal 22, so that the connection terminal 22 is the forced grounding switch 25 and the current limiting resistor 26. It is connected to the grounding device 24 via a series circuit and grounded to the ground. As a result, the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, the ground, the current limiting resistance 26, the forced ground switch 25, the connection terminal 22, the circuit to be inspected, and the negative electrode of the DC power supply device 11 are closed. (Exploration current circuit) is formed. Further, a closed circuit (voltage dividing midpoint diversion circuit) of the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply device 11 is also formed. Therefore, a direct current flows from the DC power supply device 11 to the exploration current circuit and the voltage dividing midpoint diversion circuit as indicated by the dotted arrows. The exploration current supplied to the inspection target circuit is a current flowing through the exploration current circuit, and this exploration current is supplied to the trip coil 21 of the circuit breaker operating device 20 of the inspection target circuit.

The exploration current flowing through the exploration current circuit is detected by the current detector 28 of the grounding unit 23. The exploration current detected by the current detector 28 is input to the voltage-current determination unit 29, and is compared and determined by the voltage-current determination unit 29 with a predetermined current reference value to determine whether the current value is good or bad. Then, the determination result is output to the message output unit 31 and the lamp display device 32. When the current value of the exploration current detected by the current detector 28 is within the range of the current reference value, it is determined that no disconnection has occurred. When the exploration current is zero, it is determined that a disconnection has occurred. If it is not zero but is less than or equal to the current reference value, it is determined that a failure other than disconnection has occurred. As described above, the voltage to ground at the connection point of the connection terminal 22 is a voltage detection internally connected in parallel to the series circuit of the forced ground switch 25 and the current limiting resistor 26 regardless of whether the forced ground switch 25 is turned on or off. The voltage of the resistor is detected by the voltage detector 27, and the voltage / current determination unit 29 compares and determines the voltage with a predetermined voltage reference value to determine whether the voltage value is good or bad.

Next, another example of the grounding unit 23 will be described. FIG. 3 is a configuration diagram showing another example of the grounding unit 23. The grounding unit 23 shown in FIG. 1 is provided with a current limiting circuit 33 added to the series circuit of the forced grounding switch 25 and the current limiting resistor 26. The current limiting circuit 33 is a circuit that adjusts the magnitude of the exploration current so that it becomes a predetermined constant value, and is configured by connecting a series circuit of the constant current diode CRD and the diode D in antiparallel.

In the constant current diode CRD, the current value increases or decreases in proportion to the applied voltage in the range of 0 [V] to Vk [V], but when it exceeds Vk [V], a constant current (pinch-off current) flows and the direction is opposite. The characteristic is an element that exhibits a constant voltage characteristic similar to the forward characteristic of the diode D. Therefore, the current limiting circuit 33 is configured by connecting a series circuit of the constant current diode CRD and the diode D in antiparallel in order to have bidirectional characteristics. Although FIG. 3 shows a current limiting circuit 33 configured by using a constant current diode CRD, the current limiting circuit 33 may be configured to flow a constant current by using a transistor.

Since the exploration current becomes a constant value by additionally providing the current limiting circuit 33, the exploration current flowing through the exploration current circuit has a constant value even if the current flowing through the voltage dividing midpoint diversion circuit shown in FIG. 2 fluctuates. Can be kept in. Further, the exploration current circuit includes the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, the ground, the current limiting resistance 26, the forced grounding switch 25, the connection terminal 22, the circuit to be inspected, and the negative electrode of the DC power supply device 11. Since it is formed by a closed circuit of, the resistance value may fluctuate depending on the circuit to be inspected, and the exploration current may also fluctuate. Even in such a case, the exploration current can be kept constant by the current limiting circuit 33, so that the current detected by the current detector 28 can be stably maintained as long as the exploration current circuit is formed. Can be detected.

FIG. 4 is a graph showing an example of the voltage-current characteristics of the current limiting circuit 33. FIG. 4 shows an example of voltage-current characteristics for a positive voltage. That is, in the region of 0 [V] to 35 [V], the current value increases in proportion to the applied voltage, and when it exceeds 35 [V], the constant current (pinch-off current) becomes 1.0 [mA]. It shows the current characteristics. As described above, the DC power supply voltage E (voltage E between the positive and negative sides) of the DC power supply device 11 is usually 110 [V], so that when the voltage dividing midpoint of the voltage dividing circuit 16 is grounded. Since the voltage between the voltage dividing midpoint and the positive voltage bus 12P is 55 [V], the voltage reference value is 55 [V].

Here, 1.0 [mA] was selected as the exploration current so that it is sufficiently smaller than the operating current of the trip coil 21 or the electromagnetic contactor used in the control circuit in order to prevent malfunction of the control circuit. This is to satisfy the condition that the value is within the measurable range of the high-sensitivity DC current clamp meter of the second embodiment described later.

When the grounding unit 23 is forcibly grounded by the forced grounding switch 25, the voltage dividing midpoint of the voltage dividing circuit 16 is grounded, so that the grounding unit 23 is connected in parallel to the voltage dividing circuit 16 and the above-mentioned voltage dividing circuit 16 is connected. A midpoint voltage divider circuit is formed. Therefore, since the resistance value between the voltage dividing midpoint and the positive electrode bus 12P decreases, the voltage between the voltage dividing midpoint and the positive electrode bus 12P decreases.

Therefore, if a voltage drop of 0 to -20% and a measurement error of ± 10% are expected at the connection point of the connection terminal 22, an allowable range of -30% to + 10% is expected. Therefore, the quality judgment of the voltage detected by the pressure detector 27 is judged to be good when the voltage reference value range Vr is in the range of 38.5 [V] to 60.5 [V]. Therefore, the current limiting circuit 33 keeps the exploration current constant even if the voltage at the connection point of the connection terminal 22 fluctuates within the voltage reference value range Vr of 38.5 [V] to 60.5 [V]. Adopt the voltage-current characteristics that can be achieved. In the above description, the positive voltage has been described, but in the case of the negative voltage, only the polarity is reversed, which is the same as in the case of the positive voltage. The voltage reference value range Vr is -38.5 [V] to -60.5 [V].

Here, the detected voltage is expected to decrease by 0 to -20% as a voltage drop, but the voltage is not limited to this. For example, when the resistance of the trip coil 21 is a value that cannot be ignored, the voltage drop in the trip coil 21 may be taken into consideration to set the voltage section forward value range Vr and determine the quality. ..

According to the first embodiment of the present invention, the grounding unit 23 is connected to the connection terminal 22 located on the DC power supply device 11 side of the circuit to be inspected, and the voltage / current determination unit 29 of the grounding unit 23 is detected by the voltage detection unit 27. Since the quality judgment is made based on whether or not the voltage to ground at the connected connection point is within the voltage reference value range Vr, the voltage division midpoint diversion circuit is formed to form a voltage division midpoint between the positive voltage bus 12P. Even if the voltage fluctuates, it is possible to accurately judge whether the voltage to ground at the connection point of the connection terminal is good or bad. Prior to the determination of the voltage range by forced grounding, it may be determined whether or not the power supply voltage is normally applied to the connection point before forced grounding. For example, soundness can be determined by connecting the forced grounding switch 25 to a desired connection location before forced grounding and then measuring the voltage before forced grounding.

Further, the forced grounding switch 25 of the grounding unit 23 is turned on, the connection point of the connection terminal 22 is grounded to the ground via the grounding device 24, and the DC exploration current limited by the current limiting resistor 26 is applied from the DC power supply device 11. The voltage / current determination unit 29 of the grounding unit 23 supplies to the circuit to be inspected, determines the quality of the exploration current flowing through the connection point detected by the current detection unit 28, and direct current based on the determination result of the voltage / current determination unit 29. Since the disconnection of the power supply circuit 14 is determined, the disconnection of the DC power supply circuit 14 can be determined even in the live wire state. Further, when the current limiting circuit 33 is provided, the magnitude of the DC exploration current becomes a predetermined constant value, so that the quality of the exploration current is not affected by the current flowing through the voltage dividing midpoint diversion circuit. The determination can be made, and the presence or absence of disconnection of the DC power supply circuit 14 can be accurately determined.

Next, a second embodiment of the present invention will be described. FIG. 5 is a configuration diagram showing an example of a wiring discriminating device for a DC power supply circuit according to a second embodiment of the present invention, and shows a case where the quality of the wiring connection of the DC power supply circuit is discriminated.

In the DC circuit of an electric station, DC power is supplied from the DC bus 12 to which the DC power supply device 11 is connected to the control circuit 15 via the switch 34 and the switchboard 13 via the DC power supply circuit 14. The switchboard 13 houses a monitoring control device that monitors and controls a control circuit 15 (not shown), and the control circuit 15 houses an operating device for operating various electric devices of an electric facility (not shown). Further, a voltage dividing circuit 16 is installed between the positive electrode bus 12P of the DC bus 12 and the negative electrode bus 12N (between the positive electrode and the negative electrode) by dividing the positive electrode and the negative electrode by resistance and grounding the middle point of the voltage dividing by resistance. The voltage dividing circuit 16 constitutes an element of the DC ground fault relay 17 for detecting the ground fault of the DC circuit, and the DC ground fault relay 17 operates when the voltage of the voltage dividing circuit 16 is out of balance.

FIG. 5 shows a case where a plurality of control circuits 15a to 15n are used. In contrast to the plurality of control circuits 15a to 15n, the positive electrode bus 12P has a positive electrode property via a switch 34aP to 34nP and a switchboard 13. DC power supply circuits 14aP to 14nP are connected to the above, and similarly, negative electrode DC power supply circuits 14aN to 14nN are connected to the negative electrode bus 12N via switches 34aN to 34nN and the switchboard 13. Further, FIG. 5 shows a case where the positive electrode DC power supply circuit 14nP connected to the positive electrode bus 12P is a DC power supply circuit 14n1P to 14nkP composed of a plurality of electric wires (k lines) for the control circuit 15n. The case where the negative electrode DC power supply circuit 14nN connected to the negative electrode bus 12N is one is shown. The negative electrode power supply circuit 14nN connected to the negative electrode bus 12N may not be combined into one, but may be provided for each DC power supply circuit 14nP connected to the positive electrode bus 12P.

Here, in checking the quality of the connection of the wiring of the DC power supply circuit 14, the wiring discriminating device of the DC power supply circuit according to the second embodiment of the present invention is connected to the DC power supply circuit 14. FIG. 5 shows a case where the wiring discriminating device is connected to the DC power supply circuit 14n1P which is the inspection target circuit.

The wiring discriminating device includes a first unit 35 and a second unit 36. The first unit 35 has the quality of the voltage and current of one end (the end opposite to the DC power supply device 11) of the inspection target circuit (DC power supply circuit 14n1P) for checking the quality of the wiring of the DC power supply circuit 14. The second unit 36 makes a determination and checks the quality of the wiring of the DC power supply circuit 14. The quality of the current at the other end (the end on the DC power supply 11 side) of the inspection target circuit (DC power supply circuit 14n1P) is determined. When the determination results of both the first unit 35 and the second unit 36 are good, it is determined that the wiring is correctly connected.

The first unit 35 and the second unit 36 are connected so as to sandwich both ends of the circuit to be inspected (DC power supply circuit 14n1P). The first unit 35 is connected to one end of the circuit to be inspected (the end opposite to the DC power supply device 11), and is composed of a connection terminal 22A, a grounding unit 23A, and a grounding device 24A. The second unit 36 is connected to the other end of the circuit to be inspected (the end on the DC power supply 11 side), and is composed of a high-sensitivity DC current clamp meter 37 and an intermediate unit 38.

The first unit 35 has the same configuration as the disconnection discriminating device of the first embodiment. The difference is that the connection terminal 22 of the disconnection determination device of the first embodiment is connected to the electric wire located on the DC power supply device 11 side of the circuit to be inspected, whereas the connection terminal 22A of the first unit 35 is the circuit to be inspected. The point connected to the electric current located outside the opposite end (one end) of the DC power supply device 11 of the (DC power supply circuit 14n1P) and the grounding unit 23A of the first unit 35 are shown in FIG. The grounding unit 23 has the current limiting circuit 33 shown, and does not include the grounding unit 23 having no current limiting circuit 33.

Similar to the disconnection determination device of the first embodiment, the grounding device 24A grounds the connection portion of the connection terminal 22A to the ground when the forced grounding switch 25 of the grounding unit 23A is turned on, and the first unit 35. Since the grounding unit 23A of the above has the same configuration as the grounding unit 23 having the current limiting circuit 33 shown in FIG. 3, the same components as the disconnection determining device of the first embodiment will be described below in duplicate. Omit.

The grounding unit 23A of the first unit 35 is the voltage value of the ground voltage at one end of the DC power supply circuit 14n1P (the end opposite to the DC power supply device 11), which is the circuit to be inspected, that is, the connection point of the connection terminal 22A. In addition to determining the quality of the search current, the quality of the exploration current flowing through the connection point of the connection terminal 22A is determined.

On the other hand, the high-sensitivity DC current clamp meter 37 of the second unit 36 detects the current at the other end (the end of the DC power supply side 11) of the DC power supply circuit 14n1P, which is the circuit to be inspected, and detects the current of the second unit 36. The intermediate unit 38 determines whether the current value of the exploration current detected by the high-sensitivity DC current clamp meter 37 is good or bad.

The high-sensitivity DC current clamp meter 37 of the second unit 36 is clamped to an electric wire located outside the other end (the end of the DC power supply side 11) of the DC power supply circuit 14n1P, which is the circuit to be inspected, and has a zero point. After making the adjustment, the DC exploration current supplied from the DC power supply device 11 is detected. The zero point adjustment of the high-sensitivity DC current clamp meter 37 is performed because the high-sensitivity DC current clamp meter 37 detects the direct current by passing an AC bias to the secondary side, so that the zero point offset is corrected. This is because the zero point adjustment is required for each measurement. As the high-sensitivity DC current clamp meter, a commercially available one (for example, a high-sensitivity DC clamp meter manufactured by Multi-Measuring Instruments Co., Ltd., M-700, DC 0 to 100 mA, resolution 0.01 mA) is adopted.

The intermediate unit 38 of the second unit 36 determines that the current value of the exploration current is good if the current value of the exploration current detected by the high-sensitivity DC current clamp meter 37 is within the range of the current reference value. The range of the current reference value shall have a width of ± 25% with respect to the exploration current (1 [mA]) maintained at a constant value by the current limiting circuit 33 of the grounding unit 23A. This is because the individual difference of the current limiting circuit and the second unit 36 are non-contact measurement and the measurement error is large (the first unit 35 is the direct measurement and the measurement error is small).

FIG. 6 is a configuration diagram showing an example of the second unit 36. As described above, the high-sensitivity DC current clamp meter 37 is clamped to the electric wire located outside the end (the other end) of the DC power supply side 11 of the inspection target circuit (DC power supply circuit 14n1P) to adjust the zero point. Then, the DC exploration current supplied from the DC power supply device 11 to the inspection target circuit (DC power supply circuit 14n1P) is detected.

The input processing unit 39 of the intermediate unit 38 inputs the exploration current detected by the high-sensitivity DC current clamp meter 37 and converts it into a signal that can be processed by the current determination unit 40. It is output to the current determination unit 40. The current determination unit 40 of the intermediate unit 38 determines the quality of the current value of the exploration current detected by the high-sensitivity DC current clamp meter, and the exploration current detected by the high-sensitivity DC current clamp meter is positive. When the exploration current is within the range of the current reference value (1 [mA]) ± 25%), it is determined that the exploration current is good, and in other cases, it is determined to be negative. The quality determination result of the current determination unit 40 is output to the output unit 30A. The high-sensitivity DC current clamp meter shall be installed with the polarity aligned with the direction of the exploration current that flows when forced grounding is performed.

The output device 30A has a message output unit 31A and a lamp display unit 32A, similarly to the output unit 30 of the grounding unit 23A shown in FIG. The message output unit 31A displays and outputs the current value of the exploration current flowing through the high-sensitivity DC current clamp meter 37 in addition to the quality determination result of the current determination unit 40. For example, when the determination result is good, the characters are displayed as good or OK, and when the judgment result is bad, the characters are displayed as no or NO. The current value is displayed numerically. As a result, it is possible to easily grasp the quality result of the current value at the clamped portion of the high-sensitivity DC current clamp meter 37 of the circuit to be inspected. Further, the lamp display unit 32A displays the determination result of the current determination unit 40 as a lamp. For example, when the judgment result is good, it is displayed in green, and when it is not, it is displayed in red. As a result, it is possible to visually grasp the quality result of the current value at the clamped portion of the high-sensitivity DC current clamp meter 37 of the circuit to be inspected.

Next, the operation of the wiring discrimination circuit will be described when the wiring of the circuit to be inspected is normal in the second embodiment of the present invention. FIG. 7 is an explanatory diagram of the path of the exploration current that flows when the forced grounding switch 35 of the grounding unit 23A is turned on when the wiring of the circuit to be inspected is normal in the second embodiment of the present invention.

FIG. 7 shows the path of the exploration current that flows when the forced grounding switch 25 of the grounding unit 23A shown in FIG. 3 of the DC power supply circuit according to the second embodiment of the present invention shown in FIG. 5 is turned on. The case where the circuit to be inspected is a DC power supply circuit 14n1P is shown. Since the circuit to be inspected is the DC power supply circuit 14n1P, the first unit 35 is connected to one end (the end opposite to the DC power supply 11) of the DC power supply circuit 14n1P which is the inspection target circuit. The 2 unit 37 is connected to the other end (the end on the DC power supply 11 side) of the DC power supply circuit 14n1P, which is the circuit to be inspected.

When the forced grounding switch 25 of the grounding unit 23A shown in FIG. 3 in the first unit 35 is turned on, the forced grounding switch 25 is connected to the connection terminal 22A, so that the connection terminal 22A is connected to the grounding device 24A and touches the ground. Be grounded. As a result, as shown in FIG. 7, the positive electrode of the DC power supply device 11, the DC bus line of the power distribution board 13, the other end of the DC power supply circuit 14n1P which is the inspection target circuit (the end on the DC power supply device 11 side), and the DC power supply. One end of the supply circuit 14n1P (the end on the opposite side of the DC power supply 11), the connection terminal 22A, the grounding device 24A of the grounding unit 23A, the ground, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply 11. , A closed circuit (exploration current circuit) is formed. Further, a circuit for the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply device 11 (voltage dividing midpoint diversion circuit) is also formed. Therefore, a direct current flows from the DC power supply device 11 to the exploration current circuit and the voltage dividing midpoint diversion circuit as indicated by the dotted arrows.

The current flowing through the exploration current circuit is the exploration current supplied to the DC power supply circuit 14n1P, which is the circuit to be inspected, and is 1 [mA] maintained at a constant value by the current limiting circuit 33 of the grounding unit 23A. Therefore, the exploration current detected by the current detector 28 of the grounding unit 23A is 1 [mA], which is within the range of the current reference value of the exploration current. Therefore, the voltage / current determination unit 29 of the grounding unit 23A has a good current value. Judge that there is.

Further, as for the voltage to ground at the connection point of the connection terminal 22A, since the voltage dividing midpoint of the voltage dividing circuit 16 is grounded as described above, the DC power supply device 11 has a DC power supply device 11 regardless of whether the forced grounding switch 25 is turned on or off. The value is about 1/2 of the DC power supply voltage E (voltage E between the positive and negative electrodes). Therefore, the ground voltage at the connection point of the connection terminal 22A detected by the voltage detector 27 of the grounding unit 23A is a value of around 55 [V], and the ground voltage at the connection point of the connection terminal 22A is within the range of the voltage reference value. Therefore, the voltage / current determination unit 29 of the grounding unit 23A determines that the voltage value is good.

On the other hand, the current value of the exploration current detected by the high-sensitivity DC current clamp meter of the second unit 37 is the current supplied from the positive electrode of the DC electric power device 11 to the inspection target circuit (DC power supply circuit 14n1P). Since the current reference value is (1 [mA]) ± 25%) in consideration of individual differences and measurement errors of the current limiting circuit, the current determination unit 40 of the intermediate unit 38 of the second unit 36 shown in FIG. 6 is searched. The current is judged to be good. As described above, since the determination results of both the first unit 35 and the second unit 36 are good, it is determined that the wiring of the inspection target circuit (DC power supply circuit 14n1P) is correctly connected.

Next, FIG. 8 shows an example of the exploration current path that flows when the wiring discriminating device is connected to the circuit to be inspected and the forced grounding switch of the grounding unit is turned on when the wiring is incorrect in the second embodiment of the present invention. It is an explanatory diagram, and FIG. 8 shows a case where there is an erroneous wiring in the DC power supply circuits 14n1P and 14n3P, a wiring discrimination device is connected to the DC power supply circuit 14n1P as an inspection target circuit, and the forced grounding switch of the grounding unit is turned on. ing.

The miswiring shown in FIG. 8 is as follows. Correctly, one end of the DC power supply circuit 14n1P (the end opposite to the DC power supply 11) and the other end of the DC power supply circuit 14n1P (the end on the DC power supply 11 side) are connected to form a DC. The figure shows where one end of the power supply circuit 14n3P (the end opposite to the DC power supply 11) and the other end of the DC power supply circuit 14n3P (the end on the DC power supply 11 side) should be connected. In 8, one end of the DC power supply circuit 14n1P (the end opposite to the DC power supply 11) and the other end of the DC power supply circuit 14n3P (the end on the DC power supply 11 side) are erroneously connected. Then, one end of the DC power supply circuit 14n3P (the end opposite to the DC power supply 11) and the other end of the DC power supply circuit 14n1P (the end on the DC power supply 11 side) are connected.

Now, suppose that the circuit to be inspected in such a state inspects the DC power supply circuit 14n1P with a wiring discriminator for the quality of the wiring connection. Since the circuit to be inspected is the DC power supply circuit 14n1P, the first unit 35 is connected to one end (the end opposite to the DC power supply 11) of the DC power supply circuit 14n1P which is the inspection target circuit. The 2 unit 37 is connected to the other end (the end on the DC power supply 11 side) of the DC power supply circuit 14n1P, which is the circuit to be inspected.

In this state, the grounding unit 23A of the first unit 35 forcibly grounds the connection terminal 22A to the ground by the grounding device 24A. That is, when the forced grounding switch 25 of the grounding unit 23A shown in FIG. 3 in the first unit 35 is turned on, the forced grounding switch 25 is connected to the connection terminal 22A, so that the connection terminal 22A is connected to the grounding device 24A. Grounded on the ground. As a result, as shown in FIG. 8, the positive electrode of the DC power supply device 11, the DC bus of the power distribution board 13, the other end of the miswired DC power supply circuit 14n3P (the end on the DC power supply 11 side), and the DC power supply. One end of the circuit 14n1P (the end on the opposite side of the DC power supply 11), the connection terminal 22A, the grounding device 24A of the grounding unit 23A, the ground, the voltage dividing midpoint of the voltage dividing circuit 16, the negative electrode of the DC power supply 11. Closed circuit (exploration current circuit) is formed. Further, a circuit for the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply device 11 (voltage dividing midpoint diversion circuit) is also formed. Therefore, a direct current flows from the DC power supply device 11 to the exploration current circuit and the voltage dividing midpoint diversion circuit as indicated by the dotted arrows.

Compared with the exploration current circuit shown in FIG. 7, the exploration current circuit shown in FIG. 8 replaces the other end of the DC power supply circuit 14n1P (the end on the DC power supply 11 side) and is miswired DC. The difference is that it passes through the other end of the power supply circuit 14n3P (the end on the DC power supply 11 side).

That is, even in the case of erroneous wiring, since the exploration current circuit is formed via one end of the DC power supply circuit 14n1P (the opposite end of the DC power supply device 11), the current detection of the grounding unit 23A Since the exploration current is detected by the device 28 and the exploration current is within the range of the current reference value, the voltage / current determination unit 29 of the grounding unit 23A determines that the current value of the exploration current is good. Further, as for the voltage to ground at the connection point of the connection terminal 22A, since the voltage dividing midpoint of the voltage dividing circuit 16 is grounded as described above, the DC power supply device 11 is used regardless of whether the forced grounding switch 25 is turned on or off. Since the value is about 1/2 of the DC power supply voltage E (voltage E between the positive and negative sides), the voltage-current determination unit 29 of the grounding unit 23A has a good voltage value to the ground at the connection point of the connection terminal 22A. Is determined to be.

In this way, even if the wiring is incorrect, the voltage / current determination unit 29 of the grounding unit 23A determines that the ground voltage and the exploration current at the connection point of the connection terminal 22A are good. This is because even if the wiring is erroneous, a wraparound voltage is generated at one end of the DC power supply circuit 14n1P (the opposite end of the DC power supply device 11).

On the other hand, the other end of the DC power supply circuit 14n1P (the end on the DC power supply 11 side) on which the high-sensitivity DC current clamp meter of the second unit 37 is clamped does not serve as a path for the exploration current circuit. No current is supplied from the positive pole of 11. As a result, the high-sensitivity DC current clamp meter of the second unit 37 does not detect the current (the detected current is zero), so that the current determination unit 40 of the intermediate unit 38 of the second unit 36 shown in FIG. Is determined to be no. Therefore, the determination result of the first unit 35 is good, but the determination result of the second unit 36 is no, so it is determined that the wiring of the inspection target circuit (DC power supply circuit 14n1P) is erroneous wiring.

Next, FIG. 9 illustrates an example of the exploration current path that flows when the wiring discriminating device is connected to another inspection target circuit and the forced grounding switch of the grounding unit is turned on in the case of the incorrect wiring shown in FIG. FIG. 9 shows a case where a wiring discriminating device is connected to the DC power supply circuit 14n3P as an inspection target circuit and the forced grounding switch of the grounding unit is turned on among the DC power supply circuits 14n1P and 14n3P of erroneous wiring. There is.

Since the circuit to be inspected is the DC power supply circuit 14n3P, the first unit 35 is connected to one end (the end opposite to the DC power supply 11) of the DC power supply circuit 14n3P which is the inspection target circuit. The 2 unit 37 is connected to the other end (the end on the DC power supply 11 side) of the DC power supply circuit 14n3P, which is the circuit to be inspected.

In this state, when the connection terminal 22A is forcibly grounded to the ground by the grounding device 24A by the grounding unit 23A of the first unit 35, as shown in FIG. 9, the positive electrode of the DC power supply device 11, the DC bus of the switchboard 13 are erroneously wired. The other end of the DC power supply circuit 14n1P (the end on the DC power supply 11 side), the one end of the DC power supply circuit 14n3P (the opposite end of the DC power supply 11), the connection terminal 22A, and the grounding unit 23A. A closed circuit (exploration current circuit) of the grounding device 24A, the ground, the middle point of the voltage dividing circuit 16 and the negative electrode of the DC power supply device 11 is formed. Further, a circuit for the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply device 11 (voltage dividing midpoint diversion circuit) is also formed. Therefore, a direct current flows from the DC power supply device 11 to the exploration current circuit and the voltage dividing midpoint diversion circuit as indicated by the dotted arrows.

In this way, since the exploration current circuit is formed via one end of the DC power supply circuit 14n3P (the opposite end of the DC power supply device 11), the exploration current is detected by the current detector 28 of the grounding unit 23A. Therefore, the voltage / current determination unit 29 of the grounding unit 23A determines that the current value of the exploration current is good. Further, since the voltage to ground at the connection point of the connection terminal 22A is about 1/2 of the DC power supply voltage E (voltage E between the positive and negative sides) of the DC power supply device 11, the voltage and current of the grounding unit 23A The determination unit 29 determines that the voltage value of the ground voltage at the connection point of the connection terminal 22A is also good.

On the other hand, the other end of the DC power supply circuit 14n3P (the end on the DC power supply 11 side) on which the high-sensitivity DC current clamp meter of the second unit 37 is clamped does not serve as a path for the exploration current circuit. No current is supplied from the positive pole of 11. As a result, the high-sensitivity DC current clamp meter of the second unit 37 does not detect the current (the detected current is zero), so that the current determination unit 40 of the intermediate unit 38 of the second unit 36 says that the exploration current is negative. judge. Therefore, the determination result of the first unit 35 is good, but the determination result of the second unit 36 is no, so it is determined that the wiring of the inspection target circuit (DC power supply circuit 14n3P) is erroneous wiring.

FIG. 10 shows an example of a search current path that flows when a wiring discriminating device is connected to the circuit to be inspected and the forced grounding switch of the grounding unit is turned on when another miswiring is performed in the second embodiment of the present invention. FIG. 10 shows a case where the DC power supply circuit 14n3P has an erroneous wiring, a wiring discriminating device is connected to the DC power supply circuit 14n1P as an inspection target circuit, and the forced grounding switch of the grounding unit is turned on.

The miswiring shown in FIG. 10 is as follows. Correctly, one end of the DC power supply circuit 14n3P (the end opposite to the DC power supply 11) and the other end of the DC power supply circuit 14n3P (the end on the DC power supply 11 side) should be connected. However, in FIG. 10, one end of the DC power supply circuit 14n1P (the end opposite to the DC power supply 11) and the other end of the DC power supply circuit 14n3P (the end on the DC power supply 11 side) are mistakenly shown. ) Is connected.

Now, suppose that the circuit to be inspected in such a state inspects the DC power supply circuit 14n1P with a wiring discriminator for the quality of the wiring connection. Since the circuit to be inspected is the DC power supply circuit 14n1P, the first unit 35 is connected to one end (the end opposite to the DC power supply 11) of the DC power supply circuit 14n1P which is the inspection target circuit. The 2 unit 37 is connected to the other end (the end on the DC power supply 11 side) of the DC power supply circuit 14n1P, which is the circuit to be inspected. Then, when the connection terminal 22A is forcibly grounded to the ground by the grounding device 24A by the grounding unit 23A of the first unit 35, as shown in FIG. 10, the positive electrode of the DC power supply device 11, the DC bus of the power distribution board 13, and the DC power supply circuit 14n1P The other end (the end on the DC power supply 11 side), one end of the DC power supply circuit 14n1P (the opposite end of the DC power supply 11), the connection terminal 22A, the grounding device 24A of the grounding unit 23A, the ground. , A closed circuit (exploration current circuit) of the voltage dividing midpoint of the voltage dividing circuit 16 and the negative electrode of the DC power supply device 11 is formed. Further, the other end of the DC power supply circuit 14n3P branched from the DC bus of the switchboard 13 and miswired (the end on the DC power supply 11 side) and one end of the DC power supply circuit 14n1P (DC power supply 11). A circuit is formed at the opposite end). Further, a circuit for the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply device 11 (voltage dividing midpoint diversion circuit) is also formed. Therefore, a direct current flows from the DC power supply device 11 to the exploration current circuit and the voltage dividing midpoint diversion circuit as indicated by the dotted arrows.

In this way, since the exploration current circuit is formed via one end of the DC power supply circuit 14n1P (the opposite end of the DC power supply device 11), the exploration current is detected by the current detector 28 of the grounding unit 23A. Therefore, the voltage / current determination unit 29 of the grounding unit 23A determines that the current value of the exploration current is good. Further, since the voltage to ground at the connection point of the connection terminal 22A is about 1/2 of the DC power supply voltage E (voltage E between the positive and negative sides) of the DC power supply device 11, the voltage and current of the grounding unit 23A The determination unit 29 determines that the voltage value of the ground voltage at the connection point of the connection terminal 22A is also good.

On the other hand, the current value of the exploration current detected by the high-sensitivity DC current clamp meter of the second unit 37 is the current supplied from the positive electrode of the DC electric power device 11 to the inspection target circuit (DC power supply circuit 14n1P). The current reference value is 1mA ± 25% in consideration of individual differences and measurement errors of the current limiting circuit, but the exploration current is divided into 14n1P and 14n2P and flows in parallel, so the exploration current is 1 / of the case of correct wiring. Since the value is around 2, the current determination unit 40 of the intermediate unit 38 determines that the exploration current is negative. In this way, since the determination result of the second unit 36 is negative, it is determined that the wiring of the inspection target circuit (DC power supply circuit 14n1P) is erroneously connected.

FIG. 11 is an explanatory diagram of an example of an exploration current path that flows when a wiring discriminating device is connected to another circuit to be inspected and the forced grounding switch of the grounding unit is turned on in the case of incorrect wiring shown in FIG. FIG. 11 shows a case where the wiring discriminating device is connected to the DC power supply circuit 14n3P of erroneous wiring as the circuit to be inspected and the forced grounding switch of the grounding unit is turned on.

Since the circuit to be inspected is the DC power supply circuit 14n3P, the first unit 35 is connected to one end (the end opposite to the DC power supply 11) of the DC power supply circuit 14n3P which is the inspection target circuit. The 2 unit 37 is connected to the other end (the end on the DC power supply 11 side) of the DC power supply circuit 14n3P, which is the circuit to be inspected.

In this state, when the connection terminal 22A is forcibly grounded to the ground by the grounding unit 23A of the first unit 35, the connection terminal 22A of the grounding unit 23A is grounded to the ground by the grounding device 24A, but the DC power supply circuit Since one end of 14n3P (the end opposite to the DC power supply 11) is not connected to the DC bus of the power distribution board 13, a circuit (exploration current circuit) connected to the DC power supply 11 is not formed. The positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode circuit of the DC power supply device 11 (voltage dividing midpoint diversion circuit) are formed.

Since the exploration current circuit is not formed in this way, the exploration current at the connection point of the connection terminal 22A (one end of the DC power supply circuit 14n3P (the opposite end of the DC power supply 11)) becomes zero, and similarly. , The voltage value of the ground voltage at the connection point of the connection terminal 22A also becomes zero. Therefore, the voltage / current determination unit 29 of the grounding unit 23A determines that the current value of the exploration current is negative, and determines that the voltage value of the ground voltage is also negative. On the other hand, since the exploration current circuit is not formed at the other end of the DC power supply circuit 14n3P (the end on the DC power supply 11 side) where the high-sensitivity DC current clamp meter of the second unit 37 is clamped, the second unit The current determination unit 40 of the intermediate unit 38 of 36 determines that the exploration current is negative. Therefore, since the determination result of the first unit 35 is negative and the determination result of the second unit 36 is also negative, it is determined that the wiring of the inspection target circuit (DC power supply circuit 14n3P) is erroneous wiring.

Although the positive electrode inspection target circuit has been described with reference to FIGS. 7 to 11 described above, the same can be applied to the negative electrode property inspection target circuit. FIG. 12 is an explanatory diagram of the path of the exploration current that flows when the forced grounding switch 35 of the grounding unit 23A is turned on when the wiring of the circuit to be inspected of the negative electrode property is normal in the second embodiment of the present invention. FIG. 12 shows a case where the circuit to be inspected is a DC power supply circuit 14nN. Since the circuit to be inspected is the DC power supply circuit 14nN, the first unit 35 is connected to one end (the end opposite to the DC power supply 11) of the DC power supply circuit 14nN which is the inspection target circuit. The 2 unit 37 is connected to the other end (the end on the DC power supply 11 side) of the DC power supply circuit 14nN, which is the circuit to be inspected.

When the connection terminal 22A is connected to the grounding device 24A by the grounding unit 23A of the first unit 35 and grounded to the ground, as shown in FIG. 12, the positive electrode of the DC power supply device 11 and the voltage dividing midpoint of the voltage dividing circuit 16 Ground, grounding device 24A of grounding unit 23A, connection terminal 22A, one end of DC power supply circuit 14nN (opposite end of DC power supply 11), other end of DC power supply circuit 14nN, which is the circuit to be inspected. A closed circuit (exploration current circuit) is formed of (the end on the DC power supply 11 side), the DC bus of the power distribution board 13, and the negative electrode of the DC power supply 11. Further, a circuit for the positive electrode of the DC power supply device 11, the voltage dividing midpoint of the voltage dividing circuit 16, and the negative electrode of the DC power supply device 11 (voltage dividing midpoint diversion circuit) is also formed. Therefore, a direct current flows from the DC power supply device 11 to the exploration current circuit and the voltage dividing midpoint diversion circuit as indicated by the dotted arrows.

Therefore, since the exploration current flows through the connection portion of the connection terminal 22A, the voltage / current determination unit 29 of the grounding unit 23A determines that the current value is good. Since the circuit is a negative electrode inspection target circuit (DC power supply circuit 14nN), the direction in which the exploration current flows is opposite to that of the positive electrode inspection target circuit shown in FIGS. 7 to 11. Further, since the circuit is the negative side inspection target circuit (DC power supply circuit 14nN), the ground voltage at the connection point of the connection terminal 22A is the DC power supply voltage E (voltage E between the positive side and the negative side) of the DC power supply device 11. ) Is about 1/2 (−55V), so the voltage / current determination unit 29 of the grounding unit 23A determines that the voltage value is good.

On the other hand, the other end of the DC power supply circuit 14nN (the end on the DC power supply 11 side), which is the place where the high-sensitivity DC current clamp meter of the second unit 37 is clamped, becomes the system path of the exploration current circuit. , High-sensitivity DC current clamp meter detects current. Therefore, the current determination unit 40 of the intermediate unit 38 of the second unit 36 determines that the exploration current is good. As described above, since the determination results of both the first unit 35 and the second unit 36 are good, it is determined that the wiring of the inspection target circuit (DC power supply circuit 14n1P) is correctly connected.

As described above, according to the wiring discriminating device of the DC power supply circuit of the second embodiment of the present invention, when checking the quality of the wiring connection, the outside of the DC power supply device 11 of the circuit to be inspected is on the opposite side. The connection terminal 22A of the first unit 35 is connected to the located electric wire, the connection terminal 22A is forcibly grounded by the grounding unit 23A of the first unit 35, and the DC exploration current limited by the current limiting resistance from the DC power supply device 11 is applied. Supply to the circuit to be inspected. Then, the voltage / current determination unit of the grounding unit 23A determines the quality of the ground voltage at the connection point of the grounding unit 23A and the exploration current flowing through the connection point. When the voltage to ground at the connection point of the grounding unit 23A satisfies the voltage reference value, it is determined that the voltage is good. Further, when the exploration current flowing through the connection point of the grounding unit 23A satisfies the current reference value, it is determined that the current is good.

On the other hand, the high-sensitivity DC current clamp meter 37 of the second unit 36 is clamped to the electric wire located outside the DC power supply device 11 side of the inspection target circuit of the DC power supply circuit 14, and the current determination unit of the intermediate unit 38 has high sensitivity. The quality of the current value of the exploration current detected by the DC current clamp meter 37 is determined. When the exploration current detected by the high-sensitivity DC current clamp meter 37 satisfies the current reference value, it is determined that the current is good.

When the determination result of the voltage / current determination unit of the grounding unit 23A is good and the determination result of the current determination unit of the intermediate unit 38 is good, it is determined that the wiring connection of the DC power supply circuit 14 is good. In other cases, it is judged as no. Therefore, even in the live-line state, it is possible to determine whether the wiring of the DC power supply circuit 14 is connected or not.

Further, since the message output unit 31A of the intermediate unit 38 outputs a message of the current value on the DC power supply 11 side of the circuit to be inspected and the determination result of the current determination unit 40, the current value on the DC power supply 11 side of the circuit to be inspected. You can easily grasp the good or bad result of. Further, since the lamp display unit 32A of the intermediate unit 38 displays the determination result of the current value on the DC power supply device 11 side of the inspection target circuit, the quality result of the current value on the DC power supply device 11 side of the inspection target circuit is visually displayed. Can be grasped.

11 ... DC power supply 12 ... DC bus 13 ... Distribution board 14 ... DC power supply circuit 15 ... Control circuit 16 ... Pressure dividing circuit 17 ... DC ground fault relay 18 ... Protective relay 19 ... Output contact 20 ... Breaker operating device 21 ... Trip Coil 22 ... Connection terminal 23 ... Grounding unit 24 ... Grounding device 25 ... Forced grounding switch 26 ... Current limiting resistance 27 ... Voltage detection unit 28 ... Current detection unit 29 ... Voltage / current determination unit 30 ... Output unit 31 ... Message output unit 32 ... Lamp display 33 ... Current limiting circuit 34 ... Switch 35 ... First unit 36 ... Second unit 37 ... High-sensitivity DC current clamp meter 38 ... Intermediate unit 39 ... Input processing unit 40 ... Current determination unit,

Claims (7)

A pressure dividing circuit is provided between the positive and negative sides of the DC bus of the DC power supply circuit that supplies DC power from the DC power supply to the control circuit for operating the electrical equipment of the electric station. , A DC power supply circuit that operates when the voltage of the voltage dividing circuit is out of balance and checks for disconnection of the DC power supply circuit having a DC ground fault relay that detects a ground fault of the DC power supply circuit. It is a disconnection discrimination device of
Check for disconnection in the DC power supply circuit during inspection. With a connection terminal for connecting to the electric wire located on the DC power supply side of the circuit to be inspected;
With a grounding device for grounding the connection point of the connection terminal to the ground;
It is equipped with a grounding unit that forcibly grounds the connection point of the connection terminal to the grounding device at the time of inspection;
The grounding unit is connected to the connection terminal, and at the time of inspection, the connection terminal is forcibly grounded to the grounding device, and a DC exploration current is transmitted from the DC power supply device from the connection point of the connection terminal to the inspection target circuit. A forced grounding switch for supplying to the forced grounding switch, a current limiting resistor connected in series to the forced grounding switch to limit the exploration current, a voltage detector for detecting the voltage to ground at the connection point of the connection terminal, and the connection terminal. It has a current detection unit that detects the exploration current flowing through the connection point, and a voltage / current determination unit that determines the quality of the voltage value and the current value detected by the voltage detection unit and the current detection unit;
A DC power supply circuit disconnection determination device, characterized in that the presence or absence of disconnection of the DC power supply circuit is checked based on the determination result of the voltage / current determination unit of the grounding unit. The direct current according to claim 1, wherein the grounding unit includes a current limiting circuit that is connected in series with the current limiting resistor and adjusts the magnitude of the probe current to a predetermined constant value. A device for determining disconnection of the power supply circuit. The grounding unit is characterized by including a message output unit that outputs a message of a voltage value detected by the voltage detection unit, a current value detected by the current detection unit, and a determination result of the voltage / current determination unit. The disconnection determining device for a DC power supply circuit according to claim 1 or 2. The disconnection determination device for a DC power supply circuit according to any one of claims 1 to 3, wherein the grounding unit includes a lamp display unit that displays a determination result of the voltage / current determination unit. .. A pressure dividing circuit is provided between the positive and negative sides of the DC bus of the DC power supply circuit that supplies DC power from the DC power supply to the control circuit for operating the electrical equipment of the electric station. , A DC power supply circuit that operates when the voltage of the voltage dividing circuit is out of balance and checks the quality of the wiring of the DC power supply circuit having a DC ground fault relay that detects a ground fault failure of the DC power supply circuit. It is a wiring discriminator of
With the first unit connected to one end of the circuit to be inspected to check the quality of wiring in the DC power supply circuit at the time of inspection;
It is equipped with a second unit connected to the other end of the circuit to be inspected during inspection;
The first unit has a connection terminal for connecting to an electric wire located outside the opposite end of the DC power supply device as one end of the circuit to be inspected.
With a grounding device for grounding the connection point of the connection terminal to the ground;
A grounding unit according to any one of claims 2 to 4 is provided for forcibly grounding the connection point of the connection terminal to the grounding device at the time of inspection;
The second unit is clamped to an electric current located outside the end on the DC power supply side as the other end of the circuit to be inspected, adjusts to the zero point, and then searches for DC supplied from the DC power supply. It has a high-sensitivity DC current clamp meter that detects current, and an intermediate unit that has a current determination unit that determines the quality of the current value of the probe current detected by the high-sensitivity DC current clamp meter;
A wiring discriminating device for a DC power supply circuit, characterized in that the quality of the wiring connection of the DC power supply circuit is checked based on the determination results of the voltage / current determination unit of the grounding unit and the current determination unit of the intermediate unit. .. The DC power supply according to claim 5, wherein the intermediate unit includes a message output unit that outputs a message of a current value detected by the high-sensitivity DC current clamp meter and a determination result of the current determination unit. Circuit wiring discriminator. The wiring discriminating device for a DC power supply circuit according to claim 5 or 6, wherein the intermediate unit includes a lamp display unit that displays a determination result of the current determination unit.

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