JPH0531944B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Technical Field The present invention relates to a test method and device for a ground fault directional relay, and in particular to a test method and its device for determining polarity when a ground fault directional relay is actually installed on a line. Regarding equipment.

Conventional technology A ground fault directional relay detects zero-sequence voltage and zero-sequence current when a ground fault occurs, compares the phases of both, and determines whether the fault is on the power supply side or the load side with the zero-sequence current transformer as the boundary. The direction is determined and a protective operation is performed. Therefore, when this type of relay is installed in a substation, if it is installed with the wrong polarity, it will not operate in the event of an accident in the operating direction, but will operate in the event of an accident in the non-operating direction, resulting in a serious problem. Therefore, when a ground fault directional relay is installed on a new line, a test to determine its polarity is always required.

A conventional test method of this kind will be explained with reference to FIG. Figure 3 is a single-line diagram for explaining the conventional test method. 1 is the main substation, 2 is the ground fault direction relay (hereinafter abbreviated as DGR) installed in the main substation 1, and the zero-phase transfer A zero-sequence current I ₀ and a zero-sequence voltage V ₀ are inputted from the flowmeter 3 and the zero-sequence voltage detector 4 . A switch for disconnecting the S zero-phase voltage detector 4 from the power supply line, 11 is a sub-substation, 12 is a DGR to be tested installed in the sub-substation 11, 13 is a zero-phase transformation of the sub-substation The secondary winding is connected to the current terminal (not shown) of the DGR. Generally, zero-phase current transformers have test terminals, and K _t and L _t indicate these test terminals. Although FIG. 3 shows the case of one sub-substation to simplify the explanation, in reality, one main substation is provided with a large number of sub-substations. The zero-phase voltage detector 4 is installed only in the main substation, and the zero-phase voltage detector 4 is installed only in the main substation.
DGRs often share the voltage detector 4 of this main substation. Reference numeral 5 denotes a test device, which is equipped with a power source that generates a simulated zero-sequence current and zero-sequence voltage, and K, L, m, and n indicate its current terminal and voltage terminal. A zero-phase voltage signal line 7 applies the voltage of the zero-phase voltage detector 4 to the DGR of the sub-substation 11. 8 indicates a power line, and M indicates a meter.
Next, when determining the polarity of the DGR of the sub-substation 11, first bring the test device 5 to the sub-substation 11 side, and connect one end of the test signal line 6 to the voltage terminals m and n of the test device 5. Then, pull the other end of the signal line 6 to the main substation 1, turn off the switch S, connect it to both ends of the zero-sequence voltage detector 4, and apply a simulated zero-sequence voltage V _p ' from the test device 5. Apply. Next, the terminals K and L of the test device 5 are connected to the test terminals K _t and L _t of the zero-phase current transformer 13, and a simulated zero-sequence current I _p ′ is supplied to the zero-phase current transformer 13. Check the operation or non-operation of the terminals and determine whether they are connected with the correct polarity.

Problems to be Solved by the Invention If the distance between the main substation and the sub-substation is close, there will not be much of a problem, but if the distance is more than 100 to 200 meters, it will take time and effort to pull the signal line 6, and If the phase voltage detector 4 is shared by many sub-substations, the signal line 6 must be moved to each sub-substation, which takes time and effort.
It takes a considerable amount of time just to determine the polarity, and there are cases where it is necessary to take the trouble to install a zero-phase voltage detector 4 at the sub-substation because the signal line cannot be stretched due to terrain or long distances. However, there was a problem that unexpected costs were incurred due to simple testing.

Measures to solve the problem A phase discrimination circuit is installed in the test equipment to determine the phase relationship between the zero-sequence voltage signal introduced into the test equipment from the outside and the zero-sequence current signal supplied from the test equipment to the device under test. , an arbitrary voltage signal given to the shared zero-sequence voltage detector is introduced as the above-mentioned zero-sequence voltage signal, and this voltage signal and the above-mentioned current signal are compared in phase, and the current signal is adjusted to the operation polarity to perform this operation. A polarity current signal is applied to the zero-phase current transformer of the device under test to check whether the DGR, which is the device under test, is operating or not, and to test whether the wiring of the DGR is correct.

Embodiment FIG. 1 is a circuit diagram of a test device 15 of the present invention, and FIG.
The figure is a wiring diagram for explaining the phase discrimination test method, and the same reference numerals as in FIG. 3 indicate the same or corresponding parts and the explanation will be omitted.

In FIG. 1, 50 is a waveform shaping circuit that converts the voltage waveform of the introduced zero-phase voltage signal Vo' into a pulse shape. 51 is a waveform shaping circuit that shapes a current simulating the zero-phase current signal Io' into a rectangular wave, and 52 is a phase discrimination circuit which inputs the waveform-shaped voltage signal Vo' and current signal _I0 ' and determines their phase relationship. Determine.
Reference numeral 53 denotes a display device, which optically or acoustically displays a signal output from the phase discrimination circuit when the polarity is in operation. Reference numeral 54 denotes a power supply device provided in the test apparatus 15, which has a regulator for adjusting current, and supplies a simulated zero-phase current signal Io'. 55 is a polarity switching switch, 56 is a current transformer, and a zero-phase current signal
A signal proportional to I ₀ ″ is supplied to the current waveform shaping circuit 51. K and L indicate current terminals, and m and n indicate voltage terminals.

Next, the test method will be explained.

First, when determining the phase relationship of the DGR of the sub-substation 11 in Fig. 2, turn on the switch S on the main substation 1 side.
is turned off, and an arbitrary voltage signal V _p ' simulating the zero-phase voltage is applied to the zero-phase voltage detector 4. Then, on the sub-substation 11 side, voltage terminals m and n of the testing device 15 are connected.
Connect to terminals m and n with the same symbol as DGR. Next, connect the current flow terminals K and L, adjust the regulator of the power supply device 54, and try to flow current through the circuit.

At this time, a signal proportional to the voltage signal V _p ' and the current signal I _p ' is determined by the phase discrimination circuit 52 whose waveform has been shaped by the waveform shaping circuits 50 and 51, and if it is the operating phase, the display device 53 acts to display the signal. be done. It will not be displayed if it is an inactive phase. In the case of a non-operating phase, if the suitability switching switch 55 is switched to change the direction of the current, an operating phase relationship will be established and the display device 53 will be activated and displayed.

In this way, the current signal for the voltage signal V _p ′
After confirming the operating phase of I _p ', the current terminals K and L of the test device 15 are connected to the test terminals K _t and 1 of the zero-phase current transformer 13, respectively.
Connect to L _t and send current to zero-phase current transformer 13,
If the DGR operates, it is determined that the DGR is correctly connected; if it does not operate, it is determined that the connection is incorrect.

Note that the embodiment described above is a case where the sub-substations share the zero-sequence voltage detector of the main substation, but the same applies between sub-substations as long as they share the zero-sequence voltage detector. Of course, you can take the test.

Effects of the Invention As described above, the present invention adds a voltage signal of an arbitrary phase to the zero-phase voltage detector of the main substation, and utilizes the zero-phase voltage signal line connecting the main substation and sub-substation. Then, the voltage signal appearing on this signal line is introduced into the test equipment 15, and the zero-sequence current of the phase that operates based on this voltage signal is judged by the phase discrimination circuit and output from the test equipment 15 to determine the DGR of the device under test. Since the phase is determined by supplying it to the zero-phase current transformer 13, there is no need to pull a separate signal line for phase determination, so phase determination tests can be performed at any distance, especially at one main substation. If there are many sub-substations in a country and each sub-substation shares the zero-phase voltage detector of the main substation, testing can be carried out by having only the test equipment in the sub-substation being tested, making it very easy to test. Easy to test. In addition, testing can be performed even when the test signal line is not drawn, and therefore, because the distance between the main substation and sub-substation is too far and the test signal line cannot be drawn, it is possible to conduct the test separately from the main substation. It exhibits extremely excellent effects, such as eliminating the need to install a zero-phase voltage detector in sub-substations and improving overall economic efficiency for testing in all respects.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
The figure is a wiring diagram for explaining the test method of the present invention.
FIG. 3 shows a wiring diagram for explaining the conventional test method. 15...Testing device, 50...Waveform shaping circuit for shaping the waveform of a voltage signal, 51...Waveform shaping circuit for shaping the waveform of a current signal, 52...Phase discrimination circuit, 5
3...Display device, 54...Power supply device, 55...Polarity switching device.

Claims (1)

[Scope of Claims] 1. A ground-fault directional relay that shares the zero-sequence voltage of a zero-sequence voltage detector installed at a substation with a ground-fault directional relay installed at another substation via a zero-sequence voltage signal line. In the test method for performing a phase discrimination test, the zero-sequence voltage detector is disconnected from the power supply line, an arbitrary zero-sequence voltage signal is applied to both ends of the zero-sequence voltage detector, and the voltage signal is applied to the side under test via the zero-sequence voltage signal line. , compare the phase with a zero-sequence current signal prepared in advance on the side under test, check the operating phase of the zero-sequence current signal with respect to the voltage signal, and connect it to the test terminal of the zero-sequence current transformer under test. 1. A method for testing a ground fault directional relay, characterized in that the phase of the ground fault directional relay to be tested is determined by supplying the ground fault directional relay. 2. Perform a phase discrimination test on a ground fault direction relay that shares the zero phase voltage of a zero phase voltage detector installed in a substation with a ground fault direction relay installed in another substation via a zero phase voltage signal line. The test device is provided with a phase determination circuit that determines the phase relationship between a zero-sequence voltage signal introduced from the zero-sequence voltage signal line and a zero-sequence current signal supplied by a power supply device in the test device, and The determination circuit determines the phase of the zero-sequence current signal that operates based on the voltage signal, and the zero-sequence current signal is supplied to the test terminal of the zero-phase current transformer of the earth fault directional relay under test to determine the operation. Test equipment for ground fault directional relays.