JP2020106507A - OCR tester - Google Patents

Abstract

To provide an OCR tester which is operated by a battery and is excellent in operation stability.SOLUTION: An OCR tester 1A or 1B includes a battery 2 for a power supply, a test current source 3 for supplying a test current to an overcurrent relay 102, a DC current source for operating a breaker 104, an operation detection circuit 5 for detecting a moment at which the overcurrent relay 102 operates, and a current switching circuit 8 for instantaneously switching a current source for supplying current to the overcurrent relay 102 from the test current source 3 to the DC current source 4 in response to an output signal of the operation detection circuit 5. The operation detection circuit 5 includes a comparator 53 and a bias adjustment circuit 58. A pulsation voltage B obtained by pulsating AC voltage outputted from the test current source 3 is inputted to a plus terminal of the comparator 53, and a pulsation voltage A obtained by performing voltage conversion and pulsation of a current value detected by a current transformer 7 for detecting an output current to the overcurrent relay 102 is inputted to a minus terminal.SELECTED DRAWING: Figure 1

Description

The present invention relates to an OCR tester used for regular inspection work of power receiving and transforming equipment.

Overcurrent relay (OCR) connected to the main circuit of the power receiving and transforming equipment is one year as one of the safety inspections specified by the safety regulations created by the business operator for private electric facilities based on the Electricity Business Act. It is required to carry out the operation characteristic test once. This test is generally performed together with a circuit breaker interlocking characteristic test (see, for example, Patent Document 1). These tests are performed using a tester that can perform both the operation characteristic test of the overcurrent relay and the interlocking characteristic test of the circuit breaker. In this specification, this tester is referred to as "OCR tester".

Hereinafter, a configuration of a conventionally known OCR tester and a test method for an overcurrent relay and a circuit breaker using the OCR tester will be described with reference to FIG. FIG. 8 is a diagram showing a state in which a conventionally known OCR tester is connected to an overcurrent relay and a circuit breaker provided in a main circuit of a power receiving and transforming facility.

As shown in FIG. 8, the distribution line 100 that constitutes the main circuit of the power receiving and transforming facility includes a current transformer 101, an overcurrent relay 102 connected to the current transformer 101, a current transformer 101 and an overcurrent relay. And a test terminal 103 provided in a circuit for connecting with 102. In addition, the power distribution wire 100 is provided with a circuit breaker 104 and a circuit breaker detection unit 105 that detects a circuit breaking operation of the circuit breaker 104 and outputs a detection signal. The output terminal of the overcurrent relay 102 is connected to a drive coil (hereinafter, this coil is referred to as a “trip coil”) 106 of an electromagnetic plunger (not shown) included in the circuit breaker 104.

An OCR tester 200 according to a conventional example is driven by an AC100V power source, and is a slider transformer 201 that is an autotransformer, a current limiting resistor 202 that facilitates protection and adjustment of output current, and a cutoff detection unit. A counter 203 that takes in the output signal of 105 and measures the operating time of the overcurrent relay 102 and the circuit breaker 104 is configured. In principle, the safety inspection of the power receiving and transforming equipment should be a blackout work to ensure the safety of the work. Therefore, in order to perform the operation characteristic test using the OCR tester 200 according to the conventional example, as shown in FIG. 8, a generator 300 that supplies AC 100V power to the OCR tester 200 is required.

The OCR tester 200 according to the conventional example is operated by operating a control knob (not shown) provided on the sliderac 201 and a selection knob (not shown) provided on the current limiting resistor 202 by a test specified by the safety regulations from the AC100V power source. Generates a current and outputs it from the current output terminal. The test current output from the current output terminal is applied to the input terminal of the overcurrent relay 102 via the current transformer 101 and the divided test terminal 103.

As a result, the overcurrent relay 102 is activated in the time period set in the overcurrent relay 102, the test current is instantaneously diverted to the trip coil 106, and the breaker 104 is activated. The interruption detection unit 105 detects the interruption operation of the circuit breaker 104 and outputs a detection signal to the OCR tester 200. The OCR tester 200 receives the detection signal of the cutoff detection unit 105 and cuts off the output of the test current to the overcurrent relay 102, and the elapsed time from the output of the test current to the cutoff time, that is, the overcurrent relay 102 and the overcurrent relay 102. The operating time of the circuit breaker 104 is measured by the counter 203. Then, when the operating current and operating time of the overcurrent relay 102 and the circuit breaker 104 are within the range specified by the overcurrent relay manufacturer and the circuit breaker manufacturer, it is determined that the overcurrent relay 102 and the circuit breaker 104 are normal.

Note that the interruption detection unit 105 is provided in the circuit breaker 104 and mechanically detects the operation of an auxiliary contact that operates in conjunction with the main contact of the circuit breaker 104, or is provided in the vicinity of the circuit breaker 104. A sound sensor or the like that detects an operation sound when the circuit breaker 104 operates can be used.

JP, 11-118862, A

By the way, the current value of the test current applied to the overcurrent relay 102 needs to be at least 40 A in consideration of the instantaneous settling value and the timed settling value set in the overcurrent relay 102. Further, in order to operate the circuit breaker 104 reliably, it is usually required to pass a current of 3 A or more through the trip coil 106, but in consideration of the winding impedance of the trip coil 106, at least 40 V or more is required. Since AC voltage is required, the power supplied to the OCR tester 200 needs to be at least 1600 VA.

Therefore, in the OCR tester 200 according to the conventional example, the built-in slidac 201 and current limiting resistor 202 inevitably become large, and the whole becomes heavy. Further, in order to perform the operation characteristic test of the overcurrent relay 102 and the interlocking characteristic test of the circuit breaker 104 by using the OCR tester 200 according to the conventional example, as described above, a large-sized electric power output of 1600 VA or more is possible. Since the generator 300 is required, the transportation of the equipment for carrying out the test becomes even larger. Therefore, when the OCR tester 200 according to the conventional example is used, the physical burden on the worker who conducts the test is large and it is difficult to improve the work efficiency.

In order to solve such a problem, the applicant of the present application previously invented a small and lightweight OCR tester driven by a battery and filed a patent application (Japanese Patent Application No. 2018-146289). The OCR tester previously invented by the applicant of the present application is the operation characteristic test of the overcurrent relay connected to the main circuit of the power receiving and transforming equipment, and the interlocking characteristic test of the circuit breaker that operates in conjunction with the operation of the overcurrent relay. In the OCR tester for performing the above, a test current source for supplying a test current to the overcurrent relay, a DC current source for operating the circuit breaker, and a test current source supplied from the test current source for receiving the test current. An operation detection circuit that detects the moment when the current relay operates, and a current source that is instantaneously switched from the test current source to the direct current source, according to the output signal of the operation detection circuit, the current source supplied to the overcurrent relay. And a switching circuit.

As described above, the OCR tester previously invented by the applicant of the present application detects the moment when the overcurrent relay operates by using the operation detection circuit, and supplies the current source to the overcurrent relay by the current switching circuit as the test current source. Since it is instantaneously switched from the DC current source to the DC current source, the operation detection circuit must be able to detect the moment when the overcurrent relay operates, stably and reliably regardless of the test current value. Further, in order to facilitate the use of the OCR tester, it is desirable that the operation detection condition of the operation detection circuit is set automatically according to the magnitude of the test current value. The OCR tester invented earlier by the applicant of the present application has room for further improvement in this respect.

Therefore, the problem to be solved by the present invention is to provide a small and lightweight OCR tester which is easy to use and excellent in operation stability.

In order to solve the above problems, one aspect of the present invention is an operation characteristic test of an overcurrent relay connected to a main circuit of a power receiving and transforming facility, and an interlocking characteristic of a circuit breaker that operates in conjunction with the operation of the overcurrent relay. In an OCR tester that performs a test, a test current source that supplies a test current to the overcurrent relay, a direct current source that operates the circuit breaker, and a test current source that receives the test current from the test current source. An operation detection circuit for detecting the moment when the overcurrent relay operates, and an electric current source supplied to the overcurrent relay is instantaneously switched from the test current source to the direct current source according to an output signal of the operation detection circuit. A current switching circuit, wherein the operation detection circuit is input to the comparator and a comparator that outputs a current switching signal when the magnitude relationship of the input signals input to the positive terminal and the negative terminal is inverted. A bias adjusting circuit for applying a DC bias voltage according to the current value of the test current output from the test current source between the input signals, and the positive terminal of the comparator has the test The pulsating voltage obtained by pulsating the AC voltage output from the current source is input, and the negative terminal of the comparator is detected by the current transformer that detects the output current to the overcurrent relay. The present invention is characterized in that a pulsating current voltage obtained by converting a current value into a voltage and converting it into a pulsating current is input. The bias adjustment circuit may be configured to automatically adjust the DC bias voltage to a predetermined value in association with an adjustment operation of the current value performed on the test current source.

According to the present invention, since a DC bias voltage corresponding to the test current value is applied between the input signals input to the comparator, each input when the overcurrent relay operates regardless of the magnitude of the test current value. The malfunction of the operation detection circuit due to the phase shift of the signal is avoided, and the operation stability of the OCR tester is improved. Problems, configurations, and effects other than those described above will be clarified by the description of the embodiments described below.

It is a figure which shows the use condition of the OCR tester which concerns on 1st Embodiment. It is a functional block diagram of the digital audio amplifier with which the OCR tester of the present invention is equipped. It is a functional block diagram of the operation detection circuit concerning an embodiment. It is a graph which shows the adjustment system of the direct-current bias voltage according to a test current value. It is a figure which shows the change of the pulsating current applied to the negative terminal and positive terminal of a comparator at the time of operation|movement of an overcurrent relay. It is a functional block diagram of the known current trip type overcurrent relay. It is a figure which shows the use condition of the OCR tester which concerns on 2nd Embodiment. It is a figure which shows the use condition of the OCR tester which concerns on a prior art example.

The configuration of the OCR tester according to the present invention will be described below for each embodiment with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, the OCR tester 1A according to the first embodiment includes a battery 2 as a power source, and unlike the conventional technique shown in FIG. 8, does not need a generator. Since the battery 2 is required to be small in size, light in weight and large in capacity, a lithium polymer battery or a lithium ferrite battery is preferably used, but the battery 2 is not limited to this. Further, the battery 2 can be used alone, or a battery pack in which a plurality of batteries are connected in series or in parallel can be used. The battery capacity may theoretically be about 30V 3000 mAh, but practically it is desirable to be 30V 6000 mAh or more. Further, the battery 2 can be built in the housing of the OCR tester 1A or can be externally attached to the OCR tester 1A.

In FIG. 1, 3 is a test current source for generating a test current of the overcurrent relay 102, 4 is a DC current source for generating an operating current of the circuit breaker 104, and 5 is an operation detection for detecting the moment when the overcurrent relay 102 operates. A circuit, 6 is a relay that is turned on or off by an operator, 7 is a current transformer that detects an output current to the overcurrent relay 102, and 8 is a overcurrent relay 102 according to a detection signal of the operation detection circuit 5. The semiconductor relay that instantly switches the current supplied from the test current source 3 to the DC current source 4, 9 is a calculation circuit that calculates the current signal output from the current transformer 7 and displays it on the ammeter 10, and 11 is A control circuit that controls the start and stop of the overcurrent relay 102 and measures the operating time of the overcurrent relay 102 and the circuit breaker 104, and 12 represents a counter circuit that displays the operating time of the overcurrent relay 102 and the circuit breaker 104. ing. In the present specification, “instantaneous” means a time of about 1 to several μS (microsecond).

As shown in FIG. 1, the test current source 3 protects the oscillation circuit 21, the digital audio amplifier 23 connected to the oscillation circuit 21 via the variable resistor 22, the output of the digital audio amplifier 23, and the digital audio amplifier 23. A current limiting resistor 24 for improving controllability of the output current of the audio amplifier 23.

The oscillation circuit 21 is for adjusting the frequency of the alternating current output from the OCR tester 1A to the electrical specifications of the power receiving and transforming facility protected by the overcurrent relay 102, and outputs a 50 Hz sine wave north of the Kanto area. The one that outputs a 60 Hz sine wave is used in the west of the Kansai area. The oscillator circuit 21 may be configured to switch the output frequency so that the same OCR tester 1A can be used all over Japan. The oscillation circuit 21 is a reference oscillation circuit that generates a sine wave voltage, and the circuit system is not particularly limited.

The variable resistor 22 sets the output current of the OCR tester 1A, adjusts the voltage of the output of the oscillation circuit 21 and supplies it to the digital audio amplifier 23. The variable resistor 22 is operated by an operator.

As shown in FIG. 2, the digital audio amplifier 23 includes an A/D conversion circuit 31, a driver circuit 32, a power amplifier circuit (FET PA circuit) 33 including a field effect transistor (FET), and a waveform shaping circuit. And an LC filter circuit 34. Since the FET PA circuit 33 outputs an alternating current of at least 40 A, it has an FET having a high-speed switching characteristic and a drain current capacity of 60 A or more as an output element. As described above, the digital audio amplifier 23 includes the FET as an output element, so that the capacity of the battery 2 can be effectively used. That is, the digital audio amplifier 23 is used only for operating the overcurrent relay 102, and its output voltage is almost dependent on the current limiting resistor 24 in view of the circuit impedance including the overcurrent relay 102. .. Therefore, the output voltage of the digital audio amplifier 23 may be about 15 V, though it depends on the selection of the resistance value of the current limiting resistor 24, and the capacity of the battery 2 can be effectively utilized.

Since the current limiting resistor 24 has a combined impedance of the circuit to which the overcurrent relay 102 is connected of 0.1Ω to 0.2Ω, which is close to a short-circuit state, the output protection of the digital audio amplifier 23 and the controllability of the output current are ensured. In order to improve, it is inserted for the purpose of limiting current in each settling current range. Generally, in order to switch the test current value in four stages of 0 to 5 A, 0 to 10 A, 0 to 25 A, and 0 to 50 A, four resistors are switched by a rotary switch or the like.

As shown in FIG. 1, the DC current source 4 is for exciting the trip coil 106 incorporated in the circuit breaker 104, and supplies the DC/DC converter 41 and the DC voltage generated by the DC/DC converter 41. It is composed of a capacitor 42 that stores electricity and a relay circuit 43 that disconnects the DC/DC converter 41 only for the time of discharging the capacitor 402. The capacitor 42 stores a DC voltage of 40 V or more necessary for operating the circuit breaker 104. The relay circuit 43 is switched from the conductive state to the cutoff state by the output signal of the operation detection circuit 5 at the timing when the overcurrent relay 102 operates.

The operation detection circuit 5 detects an increase in the AC voltage output from the test current source 3 and a decrease in the test current value detected by the current transformer 7 when the overcurrent relay 102 operates. As shown, the current value detected by the current transformer 7 is converted into voltage, amplified by the amplifier circuit 51 to a predetermined voltage, and then pulsated by the first rectifier circuit 52. Further, a positive DC bias voltage adjusted by the bias adjustment circuit 58 is applied to the pulsating current voltage pulsated by the first rectifier circuit 52, and is input to the minus (−) terminal of the comparator 53. On the other hand, the AC voltage output from the test current source 3 is pulsated by the second rectifier circuit 54 and input to the plus (+) terminal of the comparator 53 via the photocoupler 55. Since the input/output circuit is insulated by including the photocoupler 55, the pulsating flow pulsated by the first rectifying circuit 52 and the pulsating flow pulsating by the second rectifying circuit 54 are mixed. Can be avoided.

The comparator 53 outputs a current switching signal when the magnitude relationship between the pulsating current voltage input to the negative terminal and the pulsating current voltage input to the positive terminal is reversed. Before the operation of the overcurrent relay 102, the comparator 53 outputs the current switching signal. as shown in FIGS. 4 (a) and 4 (b), and the peak value V _B of the pulsating voltage B which is input to the peak value V _a and the positive terminal of the pulsating voltage a inputted to the negative terminal It has been adjusted to be about the same. Further, the DC bias voltage V _bias adjusted by the bias adjusting circuit 58 is added to the pulsating current voltage A input to the negative terminal. As is clear from the comparison between FIG. 4A and FIG. 4B, the DC bias voltage V _bias is higher as the peak value V _A of the pulsating current voltage A input to the negative terminal is higher, that is, the test current source. The higher the output current value of No. 3, the larger the adjustment value. 4(a) and 4(b), in order to facilitate understanding, the relationship between the peak value V _{A of} the pulsating current voltage _A , the peak value V _B of the pulsating current voltage B, and the DC bias voltage V _bias is shown. Is displayed more extreme than it actually is.

As shown in FIG. 3, the bias adjustment circuit 58 includes a variable resistor 58a for adjusting the DC bias voltage and one fixed resistor 58b for removing the influence on the output impedance of the rectifier circuit 52. Therefore, the resistance value of the variable resistor 58a is adjusted in association with the operation of the variable resistor 22 included in the test current source 3. That is, the variable resistor 58a and the variable resistor 22 are coaxially arranged on one operation shaft (not shown), and increase the current value (test current value) of the test current output from the test current source 3. When the variable resistor 22 is operated in the direction, the variable resistor 58a is automatically operated in the direction in which the positive DC bias voltage applied to the pulsating flow pulsated by the first rectifying circuit 52 increases. Is configured. As a result, the DC bias voltage V _bias having a magnitude corresponding to the test current value is applied to the pulsating current voltage A input to the negative terminal. The DC bias voltage V _bias takes into consideration the phase shift of the pulsating current voltages A and B, the noise superimposed on the pulsating current voltages A and B, the sensitivity of the operation detecting circuit 5, and the like to prevent the operation detecting circuit 5 from malfunctioning. , And an appropriate value that can maintain good sensitivity. The specific value of the DC bias voltage V _bias is obtained by experiments or simulations.

The bias adjustment circuit 58 does not necessarily need to be linked to the operation of the variable resistor 22 provided in the test current source 3, and may be configured such that an operator manually adjusts the DC bias voltage.

The operation of the operation detection circuit 5 according to the embodiment will be described below.

Before the overcurrent relay 102 operates, as shown in FIGS. 4A and 4B, the peak value V _A of the pulsating current voltage A input to the negative terminal of the comparator 53 and the comparator 53. Is adjusted so that the peak value V _B of the pulsating current voltage B input to the positive terminal of the above becomes approximately the same. Further, the DC bias voltage V _bias adjusted by the bias adjusting circuit 58 is added to the pulsating current voltage A input to the negative terminal of the comparator 53. Before the overcurrent relay 102 operates, the phase of the pulsating current voltage A input to the negative terminal of the comparator 53 and the phase of the pulsating current voltage B input to the positive terminal of the comparator 53 are in phase, Further, since the DC bias voltage V _bias adjusted by the bias adjusting circuit 58 is added to the pulsating current voltage A input to the negative terminal of the comparator 53, the pulsating current input to the negative terminal of the comparator 53 is added. The voltage A is always higher than the pulsating current voltage B input to the plus terminal of the comparator 53. Therefore, the current switching signal is not output to the output terminal of the comparator 53.

On the other hand, at the moment when the overcurrent relay 102 operates (OCR operating point), the test current instantaneously commutates from the overcurrent relay 102 to the trip coil 106, and therefore, as shown in FIG. The pulsating current voltage A input to the negative terminal of the voltage decreases to a level corresponding to the value of the current flowing through the trip coil 106. On the other hand, the pulsating voltage B input to the positive terminal of the comparator 53 rises because the test current commutates from the overcurrent relay 102 to the trip coil 106 and the voltage drop due to the current limiting resistor 24 decreases. That is, since the impedance of the trip coil 106 is larger than the impedance of the overcurrent relay 102, at the moment when the overcurrent relay 102 operates, the test current decreases and the output voltage of the test current source 3 increases. It will be. Then, when the pulsating voltage B input to the positive terminal of the comparator 53 exceeds the pulsating voltage A input to the negative terminal of the comparator 53 (comparator output point), a current switching signal is output from the comparator 53. Then, the semiconductor relay 8 operates and the current source supplied to the overcurrent relay 102 is switched from the test current source 3 to the direct current source 4.

Note that, in FIG. 5, the pulsating current voltages A and B are illustrated after the output point of the comparator for ease of understanding, but the current switching signal is output from the comparator 53 and the semiconductor relay 8 operates. After that, the current source supplied to the overcurrent relay 102 is switched from the test current source 3 to the DC current source 4, and therefore disappears.

In the operation detection circuit 5A of this example, in order to stably maintain the current switching signal for a short time, the current switching signal output from the comparator 53 is input to the signal temporary holding circuit 57 and output as the control signal of the semiconductor relay 8. doing. Since the output voltage of the amplifier circuit 51 is low, the first rectifier circuit 52 uses an absolute value circuit such as an IC arithmetic element. On the other hand, as the second rectifier circuit 54, a diode bridge can be used. A monostable multivibrator can be used as the signal temporary holding circuit 57.

Returning to FIG. 1, the relay 6 is a normally open type relay, and is switched to a conductive state by an operator operating a measurement start switch 11a attached to the control circuit 11. As a result, the output of the test current from the current output terminal 1a of the OCR tester 1A to the overcurrent relay 102 is started. It should be noted that the relay 6 is omitted, and when the operator operates the measurement start switch 11a, the control circuit 11 controls the semiconductor relay 8 to perform a test from the current output terminal 1a of the OCR tester 1A to the overcurrent relay 102. It is also possible to adopt a configuration in which output of current is started.

The semiconductor relay 8 is a current switching circuit that instantaneously switches the current supplied to the overcurrent relay 102 from the test current source 3 to the direct current source 4 at the moment when the overcurrent relay 102 operates, and is an IC relay that uses an FET. It is composed of The semiconductor relay 8 only needs to be capable of instantaneously switching the current supplied to the overcurrent relay 102 from the test current source 3 to the direct current source 4 at the moment when the overcurrent relay 102 operates, and the circuit shown in FIG. It is not limited to the configuration.

The arithmetic circuit 9 amplifies and calculates the output voltage of the current transformer 7, measures the current value of the current output to the overcurrent relay 102, and causes the ammeter 10 to display the measured value.

The control circuit 11 includes a measurement start switch 11a, and has functions of controlling output on/off control, measuring output time (time from operation of the measurement start switch 11a to operation of the circuit breaker 104), and the like. There is. The counter circuit 12 counts the output time and displays it on the display unit. Thereby, the operating time of the overcurrent relay 102 and the circuit breaker 104 is detected.

As described above, the operation detection circuit 5A of this example inputs the pulsating current voltage A that decreases at the OCR operating point to the negative terminal of the comparator 53, and the pulsating current voltage B that increases at the OCR operating point of the comparator 53. Since it is input to the plus terminal, a large DC bias voltage V _bias corresponding to the increase of the pulsating current voltage B at the OCR operating point can be applied to the pulsating current voltage A. Therefore, the operation detection circuit 5A of the present example is superimposed on a larger phase shift generated between the pulsating current voltages A and B or the pulsating current voltages A and B as compared with the OCR tester previously filed by the applicant of the present application. Greater noise can be tolerated and operation stability is excellent.

Hereinafter, the test method of the operation characteristic test using the OCR tester 1A according to the first embodiment will be described. In the following, a case will be described as an example in which the power distribution wire 100 of the power receiving and transforming facility is provided with an overcurrent relay 102 of a current trip type.

As shown in FIG. 6, the current trip type overcurrent relay 102 includes a main circuit 112 having a built-in off contact 111 through which a load current flowing from the current transformer 101 or the like flows, and a transformer for detecting the current of the main circuit 112. The output current value of the current transformer 113 is compared with the set current value of the built-in operation setting circuit, and when it is determined that the output current value of the current transformer 113 exceeds the set current value of the operation setting circuit, a predetermined value is determined. The control circuit 114 outputs a control signal. Then, when the control circuit 114 determines that the output current value of the current transformer 113 exceeds the set current value of the operation setting circuit, the off-contact incorporated in the main circuit 112 has a time limit determined by the set current value. 111 is actuated, and the current flowing into the overcurrent relay 102 is flown into the trip coil 106 incorporated in the circuit breaker 104. This breaks the circuit breaker 104.

When carrying out the operation characteristic test, as shown in FIG. 1, the current output terminal 1a of the OCR tester 1A is connected to the test terminal 103, and the output terminal of the interruption detection unit 105 is connected to the control circuit 11.

Next, the operator operates the measurement start switch 11a provided in the control circuit 11 to adjust the variable resistor 22, and the current output terminal 1a of the OCR tester 1A to the overcurrent relay 102 of the overcurrent relay 102 via the test terminal 103. At the input terminal, a current value necessary for driving the overcurrent relay 102, for example, 40A which is twice the instantaneous settling current value (minimum 20A) in the case of an instantaneous characteristic test is set and output. As a result, the overcurrent relay 102 operates in the time period set in the overcurrent relay 102.

The operation detection circuit 5 detects the moment when the overcurrent relay 102 operates from the output signal of the current transformer 7 and the output voltage of the test current source 3, generates a current switching signal, and sends the current switching signal to the semiconductor relay 8. Send. As a result, the current source supplied from the current output terminal 1a to the overcurrent relay 102 is instantaneously (about 1 to several μS) switched from the test current source 3 to the DC current source 4, and the DC current stored in the capacitor 42 is stored. Flows into the trip coil 106, and the circuit breaker 104 is switched to the breaking side. The operation of the circuit breaker 104 at this time is detected by the interruption detection unit 105, and the interruption detection unit 105 outputs a detection signal to the control circuit 11.

The counter circuit 12 measures the elapsed time from the output of the test current to the interruption, that is, the operation time of the overcurrent relay 102 and the circuit breaker 104. When the operating current and operating time of the overcurrent relay 102 are within the range specified by the overcurrent relay manufacturer and the circuit breaker manufacturer, the control circuit 11 determines that the overcurrent relay 102 and the circuit breaker 104 are normal.

Since the OCR tester 1A according to the first embodiment uses the battery 2 as a power source, the whole can be made small and lightweight. In addition, since the OCR tester 1A according to the first embodiment includes the oscillation circuit 21 and the digital audio amplifier 23 in the test current source 3, the output current of the battery 2 causes an alternating current of at least 40A necessary for the operation of the overcurrent relay 102. The test current can be efficiently generated. Furthermore, since the OCR tester 1A according to the first embodiment outputs the DC voltage stored in the capacitor 42 to the trip coil 106 after the operation of the overcurrent relay 102, the circuit breaker 104 can be operated. Need only be continued for a momentary time when the trip coil 106 is activated, so the capacity of the DC power supply is small, and the charge accumulated in the capacitor 42 can be used.

To explain this point in more detail, the voltage of the test current source 3 for operating the overcurrent relay 102 has a load impedance of 0.1Ω to 0.2Ω, which is very small. Therefore, even if the current limiting resistor 24 is added. It should be 15V or higher. Therefore, theoretically, the power capacity should be 40 A×15 V and 600 W or more. On the other hand, the operating voltage of the circuit breaker 104 is often regulated to have an inflow current to the trip coil 106 of 3 A or more, and thus an AC voltage of 40 V or more is required. Therefore, in the test current source 3 that operates the overcurrent relay 102, even if the current is commutated to the circuit breaker 104 as it is, the circuit breaker 104 cannot operate or the operation becomes unstable.

The OCR tester 1A of the first embodiment generates the operating current of the overcurrent relay 102 and the operating current of the circuit breaker 104 from the output of the battery 2, respectively, and the semiconductor relay 8 generates the overcurrent at the moment when the overcurrent relay 102 operates. Since the current source supplied to the relay 102 is instantaneously switched from the test current source 3 to the direct current source 4, the circuit breaker 104 can be operated stably.

[Second Embodiment]
Hereinafter, the configuration of the OCR tester 1B according to the second embodiment will be described with reference to FIG. As shown in FIG. 7, the OCR tester 1B according to the second embodiment is different from the OCR tester 1A according to the first embodiment in the test mode of the overcurrent relay 102 and the circuit breaker 104, and the operation characteristic test of the overcurrent relay 102. And a mode changeover switch 8a, 8b for performing only the first mode for performing both the interlocking characteristic test of the circuit breaker 104 or the second mode not performing the interlocking characteristic test of the circuit breaker 104. It is characterized by the addition of.

The mode selector switch 8a is manually switched by the user of the OCR tester 1B. When the user switches the mode selector switch 8a to the closed state, the current stored in the DC current source 4 is supplied to the circuit breaker 104 at the moment when the overcurrent relay 102 operates, so the test is performed in the first mode. It can be performed. On the other hand, when the user switches the mode changeover switch 8a to the open state, the current stored in the DC current source 4 is not supplied to the circuit breaker 104 even after the overcurrent relay 102 operates, so The test can be performed in two modes. In this case, since the operation signal is directly input from the operation detection circuit 5 to the control circuit by switching the mode changeover switch 8b to the operation detection circuit 5 side, the operation time of the overcurrent relay 102 can be measured. Others are the same as those of the OCR tester 1A according to the first embodiment, and therefore, corresponding parts will be denoted by the same reference numerals and description thereof will be omitted.

Since the OCR tester 1B according to the second embodiment is configured as described above, it becomes possible to separately perform the operation characteristic test of the overcurrent relay 102 and the interlocking characteristic test of the circuit breaker 104, and perform the operation in the power receiving state. It becomes possible to carry out the operation characteristic test of the overcurrent relay 102 of FIG. Further, since the operation characteristic test of the overcurrent relay 102 can be independently performed, the noise problem associated with the operation of the circuit breaker 104 can be solved.

The scope of the present invention is not limited to the above-described embodiment, and various modifications, additions or deletions can be made without departing from the scope of the present invention.

For example, in the above embodiment, the battery 2 was used as the power source, but a generator may be used as the power source instead of the battery. In this case, the test current source 3 is provided with a slidac. As described above, in the OCR testers 1A and 1B of the embodiment, the test current source 3 and the DC current source 4 are configured differently, so that it is sufficient to include a small sliderac as compared with the related art, and a small generator. Can be used to perform an operation characteristic test of the overcurrent relay 102 and an interlocking characteristic test of the circuit breaker 104. Therefore, the operation characteristic test of the overcurrent relay 102 and the interlocking characteristic test of the circuit breaker 104 can be easily performed.

In addition, by adding a switching tap of the current limiting resistor 24 to change the output current value small (in mA unit) and add a small capacity voltage source that can change the phase with this current and the output voltage, It can also be used as a tester for a tangential relay (DGR).

1A, 1B...OCR tester, 1a...Current output terminal, 2...Battery, 3...Test current source, 4...Direct current source 5,5A,5B,5C,5D...Operation detection circuit, 6...Relay,7... Sink, 8... Semiconductor relay (current switching circuit), 8a, 8b... Mode switching switch, 9... Arithmetic circuit, 10... Ammeter, 11... Control circuit, 11a... Measurement start switch, 12... Counter circuit, 21... Oscillation Circuit, 22... Variable resistor, 23... Digital audio amplifier, 24... Current limiting resistor, 31... A/D conversion circuit, 32... Driver circuit, 33... FET PA circuit, 34... LC filter circuit, 41... DC/ DC converter, 42... Capacitor, 43... Relay circuit, 51... Amplification circuit, 52... Rectifier circuit, 53... Comparator, 54... Rectifier circuit, 55... Photocoupler, 56... Phase compensation circuit, 57... Signal temporary holding circuit, 58... Bias adjustment circuit, 58a... Variable resistor, 58b... Fixed resistor, 100... Distribution line, 101... Current transformer, 102... Overcurrent relay, 103... Test terminal, 104... Circuit breaker, 105... Break detection unit , 106... Trip coil, 111... Off contact, 112... Main circuit, 113... Current transformer, 114... Control circuit.

Claims (2)

In an OCR tester that performs an operating characteristic test of an overcurrent relay connected to a main circuit of a power receiving and transforming facility and an interlocking characteristic test of a circuit breaker that operates in conjunction with the operation of the overcurrent relay,
A test current source that supplies a test current to the overcurrent relay, a DC current source that operates the circuit breaker, and a moment when the overcurrent relay operates in response to the supply of the test current from the test current source is detected. An operation detection circuit, and a current switching circuit that instantaneously switches the current source supplied to the overcurrent relay from the test current source to the direct current source according to an output signal of the operation detection circuit,
The operation detection circuit includes a comparator that outputs a current switching signal when the magnitude relationship of the input signals input to the positive terminal and the negative terminal is inverted, and the input signal that is input to the comparator. A bias adjusting circuit for applying a DC bias voltage according to the current value of the test current output from the test current source,
The positive terminal of the comparator, the pulsating voltage obtained by pulsating the AC voltage output from the test current source is input, the negative terminal of the comparator, to the overcurrent relay An OCR tester characterized by inputting a pulsating current voltage obtained by converting a current value detected by a current transformer that detects an output current into a pulsating current. An OCR tester, wherein the bias adjustment circuit automatically adjusts the DC bias voltage to a predetermined value in association with an operation of adjusting the current value performed on the test current source.

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