JPS637116A - Failure detector of enclosed electric equipment - 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 [Industrial Field of Application] The present invention relates to an accident detection device for sealed electrical equipment used in electrical stations such as substations.

[Prior Art] Conventionally, detection of accidents such as ground faults and short circuits in live parts in open electrical stations has been carried out using current transformers attached to live parts and relays attached to them. The accident section was identified by Electrical Station Q by visually observing the condition of electrical equipment.

In contrast, closed-type electrical v
In electrical stations where II equipment is installed, it is not possible to visually see the inside of electrical equipment, so it is not possible to visually identify the accident section. However, there is no difference between open and closed electrical stations in that it is necessary to identify the accident section and take prompt restoration measures.

In order to deal with this, it may be possible to divide the sealed electrical equipment into small sections and install a current transformer in each section, but this would only make the equipment more expensive. However, since a considerable amount of space is required inside the container to install the current transformer, it is unavoidable that the equipment will become larger, and sealed electrical equipment is adopted to downsize the equipment. The benefits of doing so will be diminished.

It has also been proposed to detect accidents by attaching a magnetic field detection means to the outside of the container and detecting the magnetic field that appears on the outside of the container when fault current flows; In the case of materials such as copper and aluminum, the magnetic field leaking from the container is small and difficult to distinguish from noise, making it extremely difficult to identify the accident zone.

[Problems to be Solved by the Invention] As described above, with the conventional technology, it is difficult to detect the magnetic field leaking outside the container, and it is difficult to distinguish between the leakage magnetic flux detection signal due to the fault current and noise. Therefore, in order to identify the accident zone, it was necessary to set up a system with extremely high precision, which caused the problem that the equipment became complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an accident detection device for a sealed electric G3 device that can identify an accident zone with a simple configuration without impairing the reliability of the sealed electric equipment.

[Means for Solving the Problems] The present invention is an accident detection device for a closed electrical separator in which a plurality of metal containers containing devices are connected via an insulating spacer, and the present invention is an accident detection device for a closed electrical separator in which a plurality of metal containers containing devices are connected via an insulating spacer. The vehicle is equipped with a magnetic field sensor and an accident area detection circuit that receives the output of the magnetic field sensor and outputs an accident area detection signal.

[Operation of the Invention] Since the insulating spacer is made of an insulating material and is non-magnetic, it does not block the leakage magnetic field generated when the conductor of the live part is energized. Therefore, when the conductor of the live part is energized, a large amount of leakage magnetic field appears at the flange part of the insulating spacer. Therefore, when a magnetic field sensor is disposed on the flange portion of the insulating spacer as described above, the magnetic field sensor senses a large amount of leakage magnetic field and detects the energized state of the conductor of the live part. Therefore, by inputting the output of this magnetic field sensor to the accident detection circuit, it is possible to immediately determine in which section the accident occurred.

[Example] The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which 1a, lb, 1c and 1d each represent a sealed container of a gas insulated switchgear. These containers are made of metal such as iron or aluminum, and are grounded by a grounding wire (not shown), and each container is filled with an insulating medium such as SF6 gas. 3a, 3b and 3c are containers 1a, l
Insulating spacers are inserted between IC and ld, respectively, and between IC and ld, and each insulating spacer is made of a non-magnetic insulator such as epoxy resin.

- In general, in closed-type electrical equipment, the container is divided into small sections, and insulating spacers are provided between the containers in adjacent sections. In many cases, the insulating spacer also serves as a member for gas separation, and each insulating spacer is airtightly connected to the containers on both sides. be done.

4u, 4v and 4W are 3 units stored in containers 1a to 1d.
phase internal conductors, these internal conductors are insulating spacers 3a
~3C. 5u, 5v and 5W are internal conductors 4u and 4v, respectively.

The gas insulated switchgear 6 is composed of a circuit breaker connected to 4W, and all of these devices are put together as one structure.

In this embodiment, insulating spacers 3a, 3b and 3C
Magnetic field sensors 7a, 7b, and 7C are arranged on the outer periphery of the flange portion. Each magnetic field sensor includes an optical magnetic field detection element such as a Faraday element that utilizes the Faraday effect of BSO (bismuth silicon oxide crystal), etc.
Hereinafter referred to as an optical magnetic field sensor. ), a search coil that generates an induced voltage when a magnetic field to be detected acts, a Hall element, or any other sensor that outputs an electrical detection signal in response to a magnetic field can be used.

By using an optical magnetic field sensor, the state of the detected magnetic field can be transmitted as an optical signal to a long distance through an optical cable, which is convenient because it can avoid the influence of noise and send high-quality signals to long distances.

Reference numeral 8 denotes an accident detection circuit which inputs detection signals obtained from the magnetic field sensors 7a to 7C and outputs a signal for locating the accident area, and this accident detection circuit is constituted by a microprocessor or the like.

Reference numeral 9 denotes an accident zone display alarm which is driven based on the operation of the accident detection circuit 8 to issue an alarm indicating the occurrence of an accident and display the accident zone.

Figures 2A and 2B show an example of how the magnetic field sensor is installed in each of the insulating spacers 3a to 3C. FIG. In FIG. 1, in order to distinguish between a plurality of containers and insulating spacers, the containers are designated by symbols 1a to 1d, and the insulating spacers are designated by symbols 3a to 3.
However, since Figure 2 shows the common structure of each insulating spacer and the containers placed on both sides of it, the containers and insulating spacers are labeled 1 and 3, respectively, in Figure 2. are doing. The magnetic field sensors 7a to 7C attached to the insulating spacers 3a to 3C shown in FIG.
Three phases are provided corresponding to W. In FIG. 2, the magnetic field sensors of the ■ and W3 phases attached to each insulating spacer are indicated by symbols 7U, 7V, and 7W, respectively.

In FIG. 2, the insulating spacer 3 is placed between the flanges 101 of the containers 1, 1, and the stud insertion hole 102 is provided in the flange 101 of the negative container.
A stud bolt 10 is provided so as to pass through a stud insertion hole 302 provided in the flange portion 301 of the insulating spacer 3 and a stud insertion hole 102 provided in the 7 flange 101 of the other container. A plurality of stud bolts are provided at predetermined intervals in the circumferential direction of the flange portion 301 of the insulating spacer, and nuts 11 are provided at both ends of each stud bolt.
．． 11 are screwed together. A washer 12 is inserted between the nut 11.11 and the flange 101 of the container, and by tightening each nut 11, the insulating spacer 3 is fastened to the container 1.1.

The three-phase magnetic field sensors 7U, 7V, and 7w each have an inner conductor 4U on the outer peripheral surface of the flange portion 301 of the insulating spacer 3,
It is arranged at the position closest to 4V and 4W. These magnetic field sensors are attached by appropriate means such as adhesion, tightening with an insulating band, or screwing. When the three-phase magnetic field sensors 7U, 7V, and 7W are placed closest to the corresponding internal conductors 4U, 4V, and 4W, stud bolts 10 are installed between the magnetic field sensors 7u to 7W and the internal conductors 4U to 4W. In order to avoid intervening
It is preferable that the stud bolt 10 be disposed so as to avoid the area between each magnetic field sensor and the corresponding live part conductor.

In the above embodiment, when a current flows through the internal conductors 4U to 4W, a magnetic field is generated. The phase of this magnetic field matches the phase of the current flowing through the internal conductors of each phase, and its value is proportional to the current flowing.

Therefore, the magnetic field sensors 7a to 7C attached to the insulating spacers 3a to 3C, respectively, detect the phase and magnitude of the current flowing through the internal conductor of each phase supported by the insulating spacers 3a to 3C, respectively.

The output of each magnetic field sensor is input to the accident detection circuit 8. The accident detection circuit 8 receives the detection signals from the magnetic field sensors attached to the insulating spacers 3a to 3c, determines the accident zone, and operates the alarm 9. Is this accident detection circuit 8 an alarm during normal times? ! ! 9 is set so that it does not operate, and when an accident occurs in any section and any magnetic field sensor detects a fault current, the fault will be detected in any section from the position of the magnetic field sensor that detected the fault current. Determine whether this has occurred.

For example, if a short circuit accident F occurs in the section of the container 1C, an overcurrent is supplied from the power supply side S to this point, and the accident point F
No current flows towards the load side.

Assuming that optical magnetic field sensors using the Faraday effect such as BSO are currently used as the magnetic field sensors 7a to 7C,
When a short circuit accident occurs at point F, the polarization angle of the light from the magnetic field sensors 7a and 7b becomes large, and the polarization angle of the magnetic field sensor 7C becomes small. Furthermore, when a sensor that generates an output voltage corresponding to the magnitude of the detected magnetic field, such as a search coil or a Hall element, is used as the magnetic field sensors 7a to 7C, F
When an accident occurs at a point, the output voltages of the magnetic field sensors 7a and 7b increase, and the output voltage of the magnetic field sensor 7C decreases. The accident detection circuit 8 determines from the states of these magnetic field sensors that an accident has occurred in the section between the insulating spacers 7b and 7C (inside the container 1C), and outputs a signal indicating this accident section. A signal for operating the alarm device 9 is output. The signal indicating the accident section drives a display means provided in the wiring m1 of the electric station to display the accident section.

FIG. 3A shows the internal conductor 4LJ in the embodiment of FIG.
FIG. 3B shows the magnetic field distribution in the cross section of the insulating spacer 3b when 4V and 4W are short-circuited, and FIG. 3B shows the magnetic field distribution in the cross section of the container 1b. The black dots shown on the internal conductors 4W and 4u indicate the current i3. Indicates that i1 is flowing, and internal conductor 4■
The X mark shown in FIG. In FIGS. 3A and 3B, the current i1 of each phase. The phases of i2 and i3 indicate the phases at time t in FIG. 3C.

As is clear from FIG. 3, the magnetic field leaking to the outer periphery of the flange portion of each insulating spacer 3 is much larger than the magnetic field leaking to the outer periphery of the container 1. In the present invention, since the magnetic field sensor is disposed at the flange portion of the insulating spacer where the leakage magnetic field is large, the detection sensitivity can be improved and the accident zone can be reliably detected.

Figure 4 shows an experimental example showing the effects of the present invention. In a gas insulated switchgear with a rated voltage of 84 KV, a three-phase short circuit current was passed through the internal conductor 4U to 4W, and the outer circumference of the aluminum container and the epoxy resin were This figure shows the results of measuring the leakage magnetic field in the circumferential direction of the flange portion 301 by attaching a BSO optical magnetic field sensor to the outer circumferential surface of the flange portion 301 of the insulating spacer made by the manufacturer. In Figure 4, curve 1
6 shows the measured value at the outer periphery of the flange portion of the insulating spacer, and curve 17 shows the measured value at the outer periphery of the container. In FIG. 4, the scale on the horizontal axis indicates the ratio (=)-11/H2) of the measured value H1 at the outer periphery of the flange portion of the insulating spacer to the measured value H2 at the outer periphery of the container.

As is clear from the results in Figure 4, the detection output at the outer periphery of the flange of the insulating spacer can be more than four times that of the outer periphery of the container. For example, it can be seen that fault current can be detected reliably.

As shown in FIG. 5, when the flange portions 101 of the containers 1a, 1b are close to the magnetic field sensor 7, a magnetic flux collecting plate 18 made of a magnetic material is placed near the magnetic field sensor 7.
Detection sensitivity can be increased by actively guiding leakage magnetic flux to the magnetic field sensor through this magnetic flux collecting plate.

Further, by disposing the magnetic flux collecting plate 18 over almost the entire circumference of the flange portion of the insulating spacer 3, the magnetic field collecting effect can be further enhanced and the detection sensitivity can be improved.

In the above description, the present invention is applied to a three-phase, bracket-type sealed electrical device, but it goes without saying that the present invention can also be applied to a phase-separated sealed electrical device. In this case, it is sufficient to attach one magnetic field sensor to each insulating spacer.

[Effects of the Invention] As described above, in the present invention, a magnetic field sensor is attached to the outer periphery of the flange portion of the insulating spacer, and an accident is detected by detecting the leakage magnetic field generated by the current flowing through the internal conductor. , the following effects can be obtained.

(a) When a detector is placed inside a container in a sealed electrical device, it may affect the insulation performance of other devices and reduce the reliability inside the container. However, in the present invention, magnetic field Since the sensor is not placed inside the container, accidents can be detected without affecting the internal reliability of the sealed electrical device. Furthermore, since there is no need to secure space for arranging an accident detection sensor inside the container, it is possible to prevent the container from becoming large.

(b) Since leakage magnetic fields are detected at the insulating spacer portion made of a non-magnetic insulating material, detection sensitivity can be increased.

(C) Since the structure of the detection section is simple, it can be implemented at low cost without complicating the structure of the electrical equipment.

(d) Fault current can be detected simply by attaching a magnetic field sensor to the flange of the insulating spacer, so it can be easily applied to existing equipment.

(e) When the insulating spacer is for gas division, it is convenient because the gas division point and the accident division point coincide.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional side view of an embodiment of the present invention, showing electrical components in blocks, and FIG. 2A. Figure B is for explaining the mounting state of the magnetic field sensor used in the present invention, Figure A is a front view showing the arrangement of the sensor when looking at the insulating spacer from the front, and Figure 8 shows the insulating spacer installed in the container. FIG. 3 is a cross-sectional view of the insulating spacer and the container taken along line 2--2 in FIG. Figures 3A to 3C are for explaining the state of the leakage magnetic field; Figure A is a magnetic field distribution diagram showing the magnetic field distribution on the cross section of the flange of the insulating spacer, and Figure B is a magnetic field distribution diagram on the cross section of the container. A magnetic field distribution diagram showing the magnetic field distribution in FIG. Fig. 4 is a diagram showing the results of determining the magnetic field distribution around the flange portion of the insulating spacer and the container outer periphery in an experimental example of the present invention, and Fig. 5 is a side view showing the main parts of another embodiment of the present invention. be. 1.1a ~ld-...container, 3.3a ~3C...
Insulating spacer, 7.7a ~ 7G, 7U ~ 7W...
Magnetic field sensor, 8... Accident detection circuit. Figure 1 Figure B Figure 2 Figure 3 @ Figure 4 @ Figure 5

Claims (1)

[Scope of Claim] An accident detection device for a sealed electrical device in which a plurality of metal containers containing devices are connected via an insulating spacer, comprising: a magnetic field sensor disposed on a flange of the insulating spacer; 1. An accident detection device for a sealed electrical appliance, comprising an accident detection circuit that receives an output of a magnetic field sensor as input and outputs an accident detection signal.