JPH0620346B2 - Accident section locator for gas insulated switchgear - Google Patents

Description

The present invention relates to a gas-insulated switchgear installed in an electric station such as a substation.

[Prior Art] A gas-insulated switchgear comprises a plurality of switchgear elements configured by accommodating devices such as a circuit breaker and a disconnector in an airtight container filled with an insulating gas such as SF6 gas according to the configuration of an electric station. It is installed and has a structure in which elements are connected to each other through an insulating spacer. As described above, in the gas-insulated switchgear, the equipment of each element is housed in a closed container, and therefore, when an accident occurs in the gas-insulated switchgear, the accident cannot be visually detected.

Therefore, as a fault locator for a gas insulated switchgear, a magnetic field sensor is attached to an insulating spacer that divides the gas insulated switchgear into a plurality of sections and divides the plurality of sections, and the fault current is detected from the output of the magnetic field sensor. An orienting device for orienting the accident section was proposed. This orienting device includes a magnetic field sensor attached to each insulating spacer that divides a plurality of sections of the gas insulated switchgear, and compares the output of each magnetic field sensor with a reference level and outputs of each phase of the magnetic field sensor and 3 A level comparison circuit that outputs a fault current detection signal when the output of the sum of phases is at or above the reference level, and a fault section location circuit that locates the section where the fault occurred from the fault current detection signal and outputs a fault section location signal This device is provided with an accident detection signal from the bus protection relay device provided in the gas insulated switchgear and uses the accident detection signal as one of the orientation conditions.

[Problems to be Solved by the Invention] Generally, since a higher-level substation is provided with a busbar protection relay device, it is possible to locate an accident section without any trouble with the above-described location device.

However, lower distribution substations, etc. that rely on the protection function of the upper substation do not have a busbar protection device in the substation, so a signal indicating that an accident has occurred in the gas-insulated switchgear is provided. Can't get In such an electric station, if the fault section is located only by the detection signal of the magnetic field sensor, if the magnetic field sensor outputs a detection signal of a predetermined level or higher due to an accident outside the substation, the load current However, when the magnetic field sensor outputs a detection signal of a predetermined level or higher due to an imbalance in the output of the transformer or an exciting inrush current of the transformer, there is a disadvantage that the orientation device malfunctions.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas insulated switchgear which does not have a busbar protective relay so that an accident section can be reliably located by using the above-mentioned magnetic field sensor type accident section locating apparatus.

[Means for Solving the Problems] Therefore, in the present invention, the output of the current transformer provided at each inlet of the power supply side circuit of the gas insulated switchgear and the current transformer provided at each outlet of the load side circuit When the difference between the current on the inlet side and the current on the outlet side of the power supply side circuit exceeds a specified level, the short circuit fault detection signal is output and the input side current and the outlet side current of the power supply side circuit An accident detection circuit that outputs a ground fault accident detection signal when the three-phase sum of the differences exceeds a predetermined level is provided, and the output of the accident detection circuit is input to the accident section location circuit. Then, the fault section locating circuit receives the fault current detection signal and the fault current detection signal and the short-circuit fault detection signal and the ground fault fault detection signal obtained from the level comparison circuit that compares the output of each magnetic field sensor with the reference level, and outputs the fault current detection signal. The short-circuit accident detection signal and the ground fault accident detection signal are used as the locating conditions to output the fault section locating signal.

[Operation of the Invention] In the above device, since the difference between the current flowing into the power supply side circuit and the current flowing out from the load side circuit of the gas insulated switchgear is in equilibrium in the state where the steady operation is performed,
The accident detection circuit does not output the short circuit accident detection signal and the ground fault accident detection signal. In addition, even if an accident occurs outside the gas-insulated switchgear, the current flowing into the power supply side circuit and the current flowing out from the load side circuit are balanced, so the short-circuit accident detection signal and ground fault accident detection signal No output. Therefore, in these states, even if the magnetic field sensor erroneously detects the exciting inrush current of the transformer as a fault current and locates the fault segment, the fault segment location signal is not output.

On the other hand, if a short-circuit accident occurs inside the gas insulated switchgear, the balance between the current flowing into the power supply side circuit and the current flowing out from the load side circuit will be lost, and the difference between the two will exceed a specified level. A short circuit accident detection signal is generated. At this time, the fault section location circuit locates the fault section based on the fault current detection signal input from the level comparison circuit and the short circuit fault detection signal obtained from the fault detection circuit, and outputs the fault section location signal. If a ground fault occurs inside the gas-insulated switchgear, the balance between the zero-phase current flowing through the power-side circuit and the zero-phase current flowing through the load-side circuit is lost, and the inlet-side current and outlet of the power-side circuit Since the three-phase sum of the difference with the side current exceeds the predetermined level, the ground fault detection signal is output. At this time, the accident section location circuit locates the failure section based on the failure current detection signal input from the level comparison circuit and the ground fault detection signal obtained from the failure detection circuit, and outputs the failure section location signal.

As described above, if an accident detection circuit for detecting an accident in the gas insulated switchgear is provided and both the detection signal of the detection circuit and the detection signal of the magnetic field sensor are used as orientation conditions, the accident in the gas insulated switchgear Since the fault section orientation signal is output only when is detected, it is possible to prevent malfunction and accurately locate the fault section.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show an embodiment of the present invention.
FIG. 1 is a single line connection diagram showing the electrical configuration of the gas insulated switchgear, FIG. 2 is an explanatory diagram illustrating a state in which a magnetic field sensor is attached to an insulating spacer, and FIG. 3 is an overall configuration of an accident section locator. FIG. 4 is a block diagram showing the configuration of the accident detection circuit.

The gas-insulated switchgear shown in Fig. 1 constitutes a distribution substation with a two-line power-receiving three-transformer bank configuration. Each block surrounded by a chain line in the figure is an airtight container filled with SF6 gas. Is an element that is configured by housing a predetermined device. Each element constitutes an independent gas section, and adjacent elements are connected via an insulating spacer.

The gas insulated switchgear shown in FIG. 1 includes a cable head CH1, a ground switch ES1, a lightning arrester LA and a disconnector DS.
Power receiving elements E11 and E12 provided with 1, and a circuit breaker C
B, circuit breaker elements E21 and E22 with grounding switches ES2 and ES3, circuit breaker elements E31 and E32 with disconnector DS2, busbar conductor C1 and disconnector DS
Busbar disconnector elements E41 to E43 provided with 3, circuit breaker elements E51 to E53 provided with circuit breaker CB2 and ground switches ES4 and ES5, and cable head CH2
Cable head elements E61 to E63 with
Disconnector elements E71 and E72 with breaker DS4
And a gas transformer connecting element E with a connecting conductor C1
8 and a transformer element E9 comprising a gas transformer GPT
Consists of.

In this gas-insulated switchgear, the elements E11, E
21 and the elements E12 and E22 form the first and second power supply side circuits P1 and P2, respectively.
31, E41, E71, E8, E42, E72, E32 and E43 form a bus bar portion BUS extending on the power supply side circuits P1 and P2. The elements E51 and E61 form a first load side circuit Q1, and the elements E52 and E62 and E53 and E63 form a second and third load side circuit Q1, respectively.
2 and Q3 are configured. 1L and 2L are first and second lines respectively connected to the upper substation, and these lines are respectively the first and second power source side circuits P1 and P.
2 and the elements E31 and E32 forming part of the busbar portion are connected to the busbar portion. The first to third load side circuits Q1 to Q3 are respectively provided with the element E.
41 to E43 are connected to the busbar portion, and the cable head elements E61 to E63 of the load side circuits Q1 to Q3 are connected to the first to third transformers Tr1 to Tr3 via cables, respectively. In the present embodiment, the current transformer CT for detecting the current flowing into the first and second power supply side circuits at the inlet side of the elements E11 and E12.
1 and CT2 are provided, and current transformers CT3 to CT5 for detecting the current flowing out from the circuits of the first to third load side circuits are provided at the outlet sides of the elements E61 to E63.

In this embodiment, the gas-insulated switchgear is divided into first to third sections I to III as shown in the figure, and in which of these sections the accident has occurred is determined. Therefore, the magnetic field sensors A and B are attached to the insulating spacers S1 and S2 that partition the sections I and II, respectively. FIG. 2 shows an example of a mounted state of the magnetic field sensor A. In this example, the magnetic field sensor A is attached to the outer surface of the insulating spacer S1 for separating the gas between the container 1 of the element E71 and the container 2 of the element E8. . The magnetic field sensor A detects a magnetic field generated by a current flowing through the conductor 3 supported by the insulating spacer S1 and outputs a detection signal corresponding to the magnitude of the current. The other magnetic field sensor B is also attached to the outer surface of the insulating spacer S2 with a similar structure, and this magnetic field sensor B outputs a detection signal corresponding to the magnitude of the current flowing through the conductor supported by the insulating spacer S2. Although only one magnetic field sensor A is shown in the drawing, actually, the three magnetic field sensors are arranged close to the three sets of conductors supported by the insulating spacers. Each of the three sets of current is detected.

As the magnetic field sensor, any device such as a Hall element, a Hall IC, a magneto diode, a magneto-optical sensor can be used.

FIG. 3 shows the configuration of an locator for locating an accident section using the output signals of the magnetic field sensors A and B of each phase as inputs. The output of the magnetic field sensor A of the U or W phase is the level phase adjustment circuit 4au. Through 4aw to the short-circuit detection level comparison circuit 5a, which compares it with the reference level. The level phase adjusting circuits 4au to 4aw adjust the output level and phase of the three-phase magnetic field sensor A, and the signals Vau to Vaw input to the level comparing circuit 5a in a steady state.
It is provided to balance the level and phase of the.
The short-circuit detection level comparison circuit 5a outputs a fault current detection signal Vsa when a signal Vau-Vaw of any phase exceeds a reference level due to a short-circuit fault. Level phase adjustment circuit 4
The outputs of au to 4aw are also input to the ground fault detection level comparison circuit 6a collectively in three phases and compared with the reference level by the comparison circuit. The ground-fault detection level comparison circuit 6a outputs a fault current detection signal Vga when a zero-phase current flows and the combined value of the outputs of the three-phase magnetic field sensor A exceeds a predetermined level.

Similarly, the output of the U-phase to W-phase magnetic field sensor B is input to the short circuit detection level comparison circuit 5b through the level phase adjustment circuits 4bu to 4bw and compared with the reference level by the comparison circuit. The short-circuit detection level comparison circuit 5b outputs a fault current detection signal Vsb when a short-circuit fault occurs and the signals Vbu to Vbw of any of the phases exceed the reference level. The outputs of the level / phase adjusting circuits 4bu to 4bw are also collectively input to the ground fault detection level comparison circuit 6b and compared with the reference level by the comparison circuit. The ground-fault detection level comparison circuit 6b outputs a fault current detection signal Vgb when a zero-phase current flows and the combined value of the outputs of the three-phase magnetic field sensor B becomes equal to or higher than a predetermined level.

The fault current detection signals Vsa, Vga, Vsb and Vgb are input to the fault section location circuit 8 together with the short circuit fault detection signal Vts and the ground fault fault detection signal Vtg obtained from the fault detection circuit 7.

As shown in FIG. 4, the accident detection circuit 7 detects the output of the current transformers CT1 and CT2 for detecting the current flowing into the power supply side circuits P1 and P2 and the current flowing out from the load side circuits Q1 to Q3. Outputs of the current transformers CT3 to CT5 are respectively passed through the ratio phase adjusting circuit 70 to the overcurrent relay O.
Short circuit fault detection circuit 71u to 72w of U phase or W phase added to C, and three sets of current detection signals flowing out from the overcurrent relay OC are collectively input to the ground fault overcurrent relay OCG. 72 and an accident detection signal output circuit 73. The overcurrent relay OC of the three-phase short circuit accident detection circuits 71u to 71w is composed of the power supply side circuits P1 and P2.
Detection signal of the current flowing into the load circuit and load side circuits Q1 to Q3
The difference between the current flowing out from the detection signal and the detection signal is detected as a differential current, and short circuit detection signals V1u to V1w are output when the differential current exceeds a predetermined level. Ratio phase adjustment circuit 70
Is to adjust the output level of the current transformers CT1 to CT5 so that the overcurrent relay OC does not perform the short-circuit accident detection operation in a steady state (makes the differential current almost zero).

The ground fault overcurrent relay OCG of the ground fault accident detection circuit 72 compares the three-phase sum (residual differential current) of the detection signals of the current transformers CT1 to CT3 with a predetermined level, and the residual differential current is determined to be a predetermined level. When the level is exceeded, the ground fault accident detection signal Vtg is output through the output circuit 73.

The accident detection signal output circuit 73 includes three sets of short circuit accident detection circuits 7
Short circuit detection signal V respectively obtained from 1u to 71w
An OR circuit OR having 1u to V1w as an input is provided, and a short circuit accident detection signal Vts is output when any one of the short circuit detection signals V1u to V1w is detected.

The accident section locating circuit 8 locates the accident section based on the output states of the magnetic field sensors A and B, and outputs an accident section locating signal indicating the orientation result when the accident detecting circuit 7 detects an accident. For example, considering the state of receiving power only from the first line 1L in FIG. 1, when an accident occurs in the section I, only the short circuit accident detection signal or the ground fault accident detection signal is generated from the accident detection circuit 7, Neither magnetic field sensor A nor B detects fault current. When an accident occurs in the section II, a short circuit accident detection signal or a ground fault accident detection signal is obtained from the accident detection circuit 7, and a fault current detection signal is obtained from the magnetic field sensor A, but the magnetic field sensor B produces an accident. No current detection signal can be obtained. When an accident occurs in the section III, at the same time that the accident detection circuit 7 outputs the short circuit accident detection signal or the ground fault accident detection signal, both the magnetic field sensors A and B detect the accident current. In this way, since the output states of the magnetic field sensors A and B differ depending on the section in which the accident has occurred, even the output state of these can locate the accident section. Table 1 shows the logic of fault section orientation when a short-circuit fault occurs while receiving power only from the first line 1L. In Table 1, "0" means that the accident detection circuit has not detected an accident and each magnetic field sensor has not detected an accident current, and "1" means that the accident detection circuit has detected an accident. It also means that each magnetic field sensor detects a fault current.

Next, Table 2 shows the orientation logic of the accident section when the power is being received from both the first and second lines 1L and 2L.

Here, "A" and "B" are magnetic field sensors A and B, respectively.
The “polarity of A” and the “polarity of B” mean the polarities of the outputs of the magnetic field sensors A and B, respectively. In this way, by including the polarity of the output of the magnetic field sensor in the determination condition, it is also possible to locate the faulty section in the case of parallel two-line power reception.

In the above embodiment, the overcurrent relay OC and the ground fault overcurrent relay OCG are used exclusively for detecting an accident in the gas insulated switchgear and have no protection function. The protection function depends on the upper substation, and if an accident occurs in the gas insulated switchgear, protection is achieved by opening the circuit breaker of the substation.

EFFECTS OF THE INVENTION As described above, according to the present invention, an accident detection circuit for detecting an accident in the gas insulated switchgear is provided, and both the magnetic field sensor, the detection output and the detection output of the accident detection circuit are provided. Since the fault section is located as a location condition, if the magnetic field sensor outputs a detection signal above a certain level due to an accident outside the substation, an imbalance occurs in the load current, or a transformer It is possible to prevent the orientation device from malfunctioning when the magnetic field sensor outputs a detection signal above a predetermined level due to the excitation inrush current of the device, and to always perform accurate orientation of the fault zone. There are advantages.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
FIG. 1 is a single line connection diagram showing the electrical configuration of the gas insulated switchgear, FIG. 2 is an explanatory diagram illustrating a state in which a magnetic field sensor is attached to an insulating spacer, and FIG. 3 is an overall configuration of an accident section locator. FIG. 4 is a block diagram showing the configuration of the accident detection circuit. E11 ~ E31, E12 ~ E32, E41 ~ E43, E51 ~ E53, E
61 to E63, E71, E72, E8, E9 ... Elements constituting a gas-insulated switchgear, I-III ... Fault locating section, S1, S2 ... Insulation provided between fault locating sections Spacer, A, B ... Magnetic field sensor, 4au-4a
w, 4bu to 4bw ... Level phase adjusting circuit, 5a, 5b ...
... short-circuit detection level comparison circuit, 6a, 6b ... ground fault detection level comparison circuit, 7 ... accident detection circuit, CT1 to CT
5: Current transformer, OC: Overcurrent relay, OCG: Ground fault overcurrent relay.

Claims (1)

[Claims] 1. A magnetic field sensor attached to each insulating spacer for partitioning a plurality of sections of a gas insulation opening device without a busbar protection relay device, and comparing the output of each magnetic field sensor with a reference level. A level comparison circuit that outputs a fault current detection signal when the output of the magnetic field sensor is equal to or higher than a reference level, and a fault section location circuit that locates a section where a fault has occurred from the fault current detection signal and outputs a fault section location signal. In the fault section locator of the gas insulated switchgear provided, the output of the current transformer provided at each inlet of the power supply side circuit of the gas insulation release device and the output of the current transformer provided at each outlet of the load side circuit When the difference between the current on the inlet side and the current on the outlet side of the power supply side circuit for each phase exceeds a specified level, the short circuit fault detection signal is output, and the input side current and the outlet side current of the power supply side circuit are output. The difference between An accident detection circuit that outputs a ground fault accident detection signal when the sum exceeds a predetermined level is provided, and the output of the accident detection circuit is input to the accident section locating circuit, and the accident section locating circuit is the accident A fault section locating device for a gas insulated switchgear, which is configured to output a fault section locating signal with the current detection signal and the short circuit fault detection signal and the ground fault fault detection signal as the locating conditions.