JPS5879426A - Fault noting relay unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground fault relay device installed at a power receiving point of a high voltage distribution line.

Conventionally, as a ground fault relay device installed at a power receiving point of a Gaozhenfei TLIM, an overcurrent ground fault relay connected to an l@O zero-phase current transformer has been widely used.

However, in recent years, improvements have been made to the power receiving point lead-in system, and the load distribution line is drawn in from the high-voltage power receiving point by a lead-in cable, and then an interrupter is installed in this load arrangement, and an automatic trip type III disconnector is installed at the responsibility demarcation point. There is a tendency for the number of cases without equipment to increase.

Along with this, the regulatory authority has instructed that ground faults that occur in the drop-in cable be detected by the consumer's ground fault detector, and for this purpose, the point m of the sheath of the drop-in cable is connected to a zero-phase current transformer. I'm trying to make it more of a load.

By the way, residual zero-sequence voltage is generated due to unbalance in ground capacity due to single-wire sections of distribution lines, unbalance in equivalent ground capacity due to automatic voltage regulators, etc., and residual zero-sequence current flows into the cable sheath grounding wire due to this. . If the remaining snow zero-phase current flowing into this cable sheath ground leg is 100, then
In a large system where the residual zero-sequence voltage is 00, it is given by the relationship , and is proportional to the cable capacitance C and *ooK, so if these are large, the residual zero-sequence current of 10° appears large. Further, in the process of cable deterioration, a large current may flow through the cable sheath grounding wire, and even if the cable does not cause dielectric breakdown, a charging current that is abnormally larger than the total jlOIi may flow.

Therefore, in the above configuration, the overcurrent ground relay may malfunction due to the residual zero-sequence current flowing through the cable sheath ground wire.

In view of the above, the present invention prevents malfunctions due to residual zero-sequence current, operates in case of failures in the own load distribution line and lead-in cable without being activated due to failures in other lines, and furthermore *
It is an object of the present invention to provide a ground fault relay device that can reliably distinguish between a cargo delivery 'ttim accident and a lead-in cable accident.

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, #4 is placed in the load arrangement via the section switch 2 and the lead-in cable 3 to the high-voltage power distribution ll1l! !
and this load arrangement [Koji 4 KFiL interrupter 5 is provided, cable 30 sheath KFiL ground II 6 is connected. A penetrating zero-phase current transformer 11 is attached to the cable 3 so that the cable 3 passes through the primary side. The cable sheath ground 116 is connected to the zero-phase current transformer 11. Load distribution line 4 is O1&1
A zero-phase flow device 12 having a through-hole Y is attached to this load distribution line 4 so as to pass through the load distribution line 4 . Another 1jkljAa
A through-type zero-phase current transformer 13 is attached to the grounding wire 6 so that the zero-phase current transformer 13 passes through the grounding wire 6 on its primary side.

The mutual phase relationship between the outputs of these three zero-phase current transformers 11 to 13 is determined, and the level of the output of the zero-phase current transformers 12 and 13 is determined.

That is, each waveform is shaped into a vE wave through the waveform shaping circuits 22, 23° 25, and the output of the zero-phase current transformer 11 is also inverted by the KNOT circuit 26 and sent to the phase discrimination circuit 2.
Guided to 7.28.29. This phase discrimination circuit 27.2
8.29 produces a 10" output when the overlapping part of the input intelligent wave is large (that is, the phase shift is small), and produces an "l" output when the overlapping part is small (the phase shift is large). The output is led to an AND circuit 30.33.The AND circuit 30.33 includes a zero-phase current transformer 1
2. A rail detection circuit 21 that produces an output when each of the output levels of 13 is greater than each of the detection levels L, , L, .
The output from 24 is also sent, and when the AND condition is satisfied, the auxiliary relays 32 and 35 are driven via the arm arm circuits 31 and 34.

Here, under normal conditions (when only the residual zero-sequence current is flowing), the ground fault point is self-fi! (load distribution @4 part excluding cable 3), other line (power supply @), and cable 3, the zero-phase current transformer 11
．． 12. Zero-sequence current II flowing in the primary side of each of 13 *
Examining the phase relationship of L e I3, it can be summarized as shown in the following table.

Next, with reference to the above table, waveforms of each part will be shown and the operation will be explained separately for each case. First, in the normal state (residual portion), since 13e11m1g are in phase with each other, the outputs of zero-phase current transformers 11, 12, and 13 are
As shown in Figures B and C, the waveform shaping circuit 25.2
The output of 2°23 becomes an in-phase rectangular wave as shown in the second diagram, B and FK. Since the rectangular wave is inverted by the NOT circuit 26, the output of the phase discrimination circuit 27.29 becomes "l",
The output of the phase discrimination circuit 28 becomes @0-K. Its*J6
AND circuits 30 and 33 are all
Even if the output @0# is 1), none of the auxiliary relays 32 and 35 will operate, so there will never be a malfunction due to the residual amount.

In the event of a fault in the own line, 11sL is in phase and 2sti is in reverse phase, and the outputs of zero-phase current transformers 11, 12, and 13 become K as shown in Figure 3 A, B, and C, respectively. And the third output circuit of the waveform shaping circuit 25.22゜23, E, F
become that way.

Therefore, each output of the phase discrimination circuit 27, 28, 29 is 11
“□Jl, @0”, and in this case I! is large, so the output B of the zero-phase current flow device 12 exceeds the detection level L1, and an output 11'' is generated from the level detection circuit 21.11
Since it is small, the output C of the zero-phase current transformer 13 is detected and the bell L,
Below, the output of the level detection circuit 24 is 10#. Therefore, “1” is generated from the AND circuit 30 and the auxiliary relay 32
is driven, but @01 is generated from the AND circuit 33 and the auxiliary relay 35 is not driven.

At the time of a narrow edge fault, Il * Il * 11 companies are in phase, and the level of 11 * 11 becomes large and zero phase current transformer 11
．． 12.13 each output welfare Figure 4 A, B, C, the fourth diagram,
It will look like B and F. The output of the level detection circuit 21 becomes 111 when it is true, but the output of the phase discrimination circuit 27. also becomes @O#, and neither of the auxiliary relays 32 and 35 operates.

When an accident occurs in cable 3, 11s11 are in phase, ! ! are in opposite phase to these, each level becomes large, and the outputs of zero-phase current transformers 11, 12, and 13 are as shown in Fig. 5A,
As shown in B and C, the level detection circuit 21.24
The output of becomes “l#”.

Each output of the waveform shaping circuit 25, 22, and 23 is
a, F, and as a result, the output of the phase discrimination circuit 27 becomes @01, and the output of the phase discrimination circuit 28.29 becomes "l#".The output of the ninth ND circuit 30 is auxiliary at °0". The relay 32 does not operate, but the output of the ANDI circuit 33 is 11.
” and the auxiliary relay 35 operates.

The auxiliary relay 32 is used for tripping the breaker 5,
Trips when own line accident occurs. The assist relay 35 is used for tripping or warning the interrupter 5, and when an accident occurs in the cable 3, a trip is made in the former case, and a KFi alarm is issued in the latter case. In any case, by operating the auxiliary relays 32 and 35, it is possible to detect whether the accident is in the cable 3 or in the own line other than the cable 3.

The phase discrimination circuit specifically includes an exclusive OR circuit 61, a transistor 63, a resistor 62, 64, 66, a capacitor 65, a 7-mi, 7-mi circuit 68, It can be configured with a mono multivibrator 69 and a NOT circuit 70. With this circuit, the A-43 six-hole wave furnace becomes as shown in FIG. 7 or FIG. 8. When the phase shift of the input signal B is small, as shown in Fig. 7, the /# pulse width at the 0 point becomes short, and the period during which the transistor 63 is on is short, and the rounding capacitor 65 is sufficiently charged. The potential at point D is level L,
, so ``1'' output is intermittently generated at 8 points.As a result, the output of monomultipolar 9 is continuously @l
”, the output of the NOT low path 70 becomes 10'. On the other hand, as shown in the 8th fI!lK, the input A.

When the phase shift of B becomes larger than a predetermined value, the pulse width at point 0 becomes longer, so the period during which the transistor 63 is on is longer and the potential at point D does not rise. The output of the mono multivibrator 69 is 101, and the output of the NOT circuit 70 is 1.
It becomes 1#.

As described above with respect to the embodiments, according to the present invention,
It is possible to detect failures in the own line without being affected by residuals,
Moreover, the accident of the lead-in cable within the own line and other load placement 1
It is possible to reliably distinguish this from the llI accident.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG.
Figures 4 and 5 are time charts showing the signals of each part in Figure 1, Figure 6 is a block diagram showing an example of the phase discrimination circuit in Figure @1, and Figures 7 and 8 are the time charts showing the signals of each part in Figure 1. 5 is a time chart showing signals of each part in the figure. 1.-High voltage distribution IIj2...Division switch 3...Leading cable 4...9 Load arrangement 11!5...Breaker 6...Cable sheath grounding wire 11.12.13.
...Zero-phase current transformer 21.24...Level detection circuit 22.23.25...Waveform shaping circuit 27.28.29...Phase discrimination circuit 26...NOT circuit 30.33... AND circuit 31. 34... Power circuit 32. 35... Auxiliary relay applicant Tateishi Electric Co., Ltd. Toad 1 Answer? Prelude: 3 times q times F paper,! 5 circles

Claims (1)

[Claims] (1) In a ground fault relay device installed at a power receiving point of a power distribution system in which a load distribution line is connected to a load distribution line from one high-voltage line via a drop-in cable, a ground-fault relay device that connects the drop-in cable and the load distribution line with a ground-fault relay. While installing the second zero-phase current transformer,
The sheath of the lead-in cable is grounded at this first zero-phase current flow device, and this cable sheath ground 1MKM
3 zero-phase current transformer is installed, and the 1st. Second. When the mutual phase of each output of the third zero-phase current transformer is determined, it becomes 4%. An earth-to-ground relay device configured to detect the level of each output of the third zero-phase current transformer.