JPS6183974A - Method for detecting ground fault point of distribution line - Google Patents

Abstract

PURPOSE:To simply detect a ground fault point, by the detection signal flowing through a distribution line and the ground fault point by injecting the same in the distribution line from a detection signal injection apparatus. CONSTITUTION:When ground fault trouble is generated in an arbitrary section Ax divided by section switches SS, reclosing is repeated in the side of a substa tion and the switches SS at both sides of the ground fault trouble generated section are closed to detect a ground fault trouble section A3. When a detection signal is injected in a distribution line 3a from a detection signal injection apparatus 8 in said fault section A3, said detection signal flows through the distribution line 3a and a ground fault point. As a result, display apparatuses H1, H3 present from the apparatus 8 to the ground fault point T are changed over from steady display to ground fault display by the detection signal. There fore, by the primary round of the detection signal from the injection point, a final point of ground fault display is detected as the ground fault point T.

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention is directed to transmitting a search signal from a search signal injection device to a distribution line in a ground fault section so as to detect a ground fault point occurring in a distribution line. This invention relates to a method for easily detecting a ground fault point by primary patrol from the search signal injection side, by injecting a search signal into the distribution line and displaying the ground fault from the injection point of the search signal injection device to the ground fault point using an appropriate number of display devices. It is something.

(Prior art) Conventionally, when a ground fault occurs in a distribution line, the substation circuit breaker is first opened, and then the substation circuit breaker is At the same time, the sectional switches on the power supply side are turned on sequentially to retransmit power to the healthy section, and when the section reaches the ground fault section, the substation circuit breaker is shut off again. When the circuit breaker of the substation is closed again, the section switch that separates the ground fault section is locked in the open state, and only the ground fault fault section is isolated, and power is retransmitted only to the healthy section. , searching for ground fault sections. Once a ground fault fault section has been found, the ground fault point is detected by repeatedly measuring the insulation resistance of related power distribution equipment installed on each utility pole in the fault section.

(Problem to be Solved by the Invention) As mentioned above, in the past, after the ground fault fault section was identified, the related power distribution equipment installed on utility poles, etc. existing in the ground fault fault section was insulated sequentially for each utility pole. Because I was measuring resistance,
There was a problem in terms of work that this required a lot of time, and there was a drawback that it took a long time to detect the ground fault point.

Structure of the Invention (Means for Solving the Problems) This invention has been made to solve the above-mentioned problems, and the method for detecting a ground fault point in a distribution line according to the invention is to When a ground fault occurs between the sectional switches, the substation repeats re-closing, thereby opening the sectional switches at both ends of the section where the fault has occurred and removing the ground fault area. In a power distribution system that detects , a plurality of display devices are arranged that display a ground fault from a normal display based on the search signal when the search signal is detected, and the search signal is injected from the search signal injection device into the distribution line, and the search signal is injected into the distribution line. The gist of the present invention is that a search signal flowing through a ground fault point causes the display device to display a ground fault indication.

(Function) With the above configuration, when a ground fault occurs in any section divided by sectional switches, the substation repeats reclosing to close the sectional switches at both ends of the section where the ground fault occurs. Open the circuit and detect the ground fault section. When a search signal is injected into the distribution line by the search signal injection device in this detected ground fault fault section, the search signal flows through the distribution line and the ground fault point. As a result, the display device located between the search signal injection device and the ground fault point changes from the normal display to the ground fault display based on the search signal. As a result, if a primary tour is performed from the injection point of the search 18 bow, the final point where the ground fault display is displayed becomes the ground fault point.

(Example) Hereinafter, a preferred example embodying the present invention will be described in Figs.
This will be explained according to FIG.

1 is a power transmission line, 2 is a circuit breaker in a substation, and 3 is a distribution line connected to the power transmission line 1 via the circuit breaker 2. Reference numeral 4 denotes a zero-phase current transformer (hereinafter referred to as ZCT) of the substation installed on the load side closest to the circuit breaker 2, and 5 represents a grounding transformer (hereinafter referred to as GPT) installed in the power transmission line 1. 4 and 5 detect a single-line ground fault occurring in the power distribution line 3, activate the directional ground fault relay 6 to trip the circuit breaker 2, and almost disconnect the power distribution line 3 from the power transmission line 1. .

A large number of section switches SS attached to utility poles 7 are arranged on the distribution line 3, and a large number of sections An (n = 1.2.3...) are connected by the section switches SS. When the circuit breakers 2 of the substation are closed and retransmitted, the circuits are sequentially closed from the power supply side.

The sectional switch SS is a conventionally known sectional switch, and when a ground fault occurs in a certain section, the substation breaker 2 opens, and then when the substation breaker 2 is reclosed, the power is turned off. Power is sequentially turned on from the side section switch SS to retransmit power to the wire section, and when the ground fault fault section is reached, the substation circuit breaker 2 is shut off again. Then, when the circuit breaker 2 of the substation is closed again, the section switch SS that separates the ground fault fault section is locked in the open state, so that only the ground fault fault section is isolated.

Reference numeral 8 denotes a search signal injection device installed below the utility pole 7, which is connected via a primary cutout PC to the three-phase load-side distribution line 3 of the section switch SS located above, and is connected to the section switch SS located above. It is grounded together with the switch SS (see Figures 1 and 4). The search signal injection device 8 injects the search signal current into the three phases at once by closing the normally open manual switch 8a. In this embodiment, the drive power source for the search signal injection device 8 uses a power transformer [R] for driving the section switch SS provided in the distribution line 3 on the power supply side, but a separate power source such as a battery is used. May be equipped.

H is a plurality of display devices provided for each phase in each section of the power distribution line 3, and are arranged at a predetermined distance from each other.

This display device H will be explained.

10 is a current transformer attached to the distribution line 3; 11 is a ground fault detection sensor connected to the current transformer 10; when a search signal 'current of a certain level or higher flows through the distribution line 3;
detecting a transformation signal output from the current transformer 10;
It is designed to output a ground fault detection signal.

Reference numeral 12 indicates the entire display section connected to the ground fault detection sensor 11. The display section 12 includes a plurality of magnetic reversal display devices arranged adjacent to each other as shown in FIGS. 7 and 8. This magnetic reversal display device will be described in detail with reference to FIGS. 5 and 6. A disk 13 magnetized at both ends with N poles and 34 fr is rotatably supported around a rotation shaft 14, and is shaped like a round bar. The stator 15 is formed to have a magnetic pole portion 15a corresponding to the S pole of the disk 13 and a magnetic pole portion 15b corresponding to the N pole of the disk 13. Note that the stator 15 is preferably formed of a material with low holding power. Both magnetic pole portions 15a.

A coil 16 is wound between the magnetic poles 15b so that the magnetic pole parts 15a and 15b are magnetized to have the same polarity as the magnetic poles at both ends of the disk 13 in the state shown in FIG.

The front side 13a and the back side 13b of the disk 13 are marked with different colors (in this embodiment, the front side 13a is black;
Red> is displayed on the back surface 13b, and is visible from below the display device H.

When the display section 12 receives the ground fault detection signal from the ground fault detection sensor 11, a drive current flows through the coil 16, and as shown in FIG. The disk 13 is magnetized to the N pole, and its N pole is attached to the magnetic pole part 15a (S pole), and its S pole is attached to the magnetic pole part 15b (N
The disc 13 is rotated inverted so as to face the pole (pole), and a mark attached to the back surface 13t) of the disc 13 is displayed on the outside. Further, the stator 15 of the display unit 12 is provided with a coil (not shown) wound in the opposite direction to the coil 16, and when a return drive current flows through this coil (not shown), the magnetic pole in the ground fault display state is The portions 15a and 15b return to the normal display polarity, and as a result, the disk 13 is reversed and returns to the normal display (see FIGS. 5 and 7).

As shown in FIG. 2, reference numeral 17 is a timer connected to the display section 12, and when a predetermined period of time (e.g., 3 to 4 hours) has elapsed since the display section 12 displayed the ground fault, the drive current is restored. is applied to the coil (not shown) to return the 'display section 12 from the ground fault display to the normal display.

In addition, 18 is a ground fault detection sensor 11 and the current transformer 10.
This is a driving power source for the display section 12 and timer 17 connected to the .

Father, this display device also has the function of displaying short circuits. One is a short-circuit detection sensor connected to the current transformer 10, and when a short-circuit current of a certain level or more flows through the distribution line 3, the sensor detects a short circuit based on a transformation signal output from the current transformer 10. A short circuit detection signal is output to the display section 12, and based on the short circuit detection signal, the display section 12 displays a short circuit as in the case of the ground fault detection. Note that the display unit 12 starts the timer 1 after a predetermined time (3 to 4 hours) from the time when the short circuit display state is entered.
By applying the return drive current from 7, the display section 12 is returned from the short circuit display to the normal display as in the case of the ground fault display.

Note that As shown in FIG. 4 is a normally closed switch.

Next, the operation of the system configured as described above will be explained.

Now, as shown in Figure 4, in section △3 of distribution line 3, a
It is assumed that a single line ground fault has occurred at one point on the phase. For convenience of explanation, only the a-phase 3a of the power distribution line 3 is illustrated in FIG.

Then, the substation ZCT4 outputs the zero-sequence current and the ZPPb0 zero-sequence voltage as a ground fault signal, a trip signal is sent to the circuit breaker 2 via the relay 6, and the substation circuit breaker 2 is opened.・Next, the substation; the circuit breaker 2 recloses the circuit, and sequentially turns on the power from the section switch SS on the power supply side to retransmit power to the healthy section, and when it reaches the ground fault section A3, the substation circuit breaker 2 is cut off again. Then, when the LFV circuit 2 of the substation is closed again, the section switch SS that separates the ground fault fault section is locked in the open state, and the ground fault fault section △
3 will be separated, and power will be retransmitted only to healthy sections.

As mentioned above, the ground fault fault section A3 can be detected by locking the sectional switch SS in the open state, so the worker then moves the ground fault fault section A3 below the sectional switch SS on the power supply side. The manual switch 8a of the arranged search signal injection device 8 is operated to close the circuit. This manual switch 8a
By the circuit closing operation, the search signal injection device 8 injects the search signal current from the load side of the sectional switch SS to each phase 3a, 3b, 3 of the distribution line.
Inject each into C.

Then, the search signal injection device 8. A circulating current flows in an open loop path passing through the distribution line 3a, the ground point T, and the search signal injection device 8, and as a result, the circuit is placed between the injection point of the search signal injection device 8 and the ground fault point T. The display devices H1 and H3 display the information.

That is, when a search signal current of a certain level or higher flows through the distribution line 3, the current transformers 10 of the display devices H1 and H3 output a transform signal based on the search signal current, and the ground fault detection sensor 11 outputs the transform signal. Outputs a ground fault detection signal in response to Then, the display unit 12 inputs the ground fault detection signal, and a drive current flows through the coil 16° based on the ground fault detection signal.

Then, the magnetic pole part 1 changes from the state shown in FIG. 5 to the state shown in FIG.
5a is magnetized as an S pole, and the magnetic pole part 15b is magnetized as an N pole, and the disk 13 is reversed so that its N pole faces the magnetic pole part 15a (S pole) and its S pole faces the magnetic pole part 15b (N pole). move. As a result, a color mark or the like attached to the back surface 13b of the disk 15 is displayed to the outside to indicate a ground fault (see FIG. 8).

On the other hand, regarding phase c, a closed loop including the ground capacitance of the distribution line 3 instead of the ground fault point 12 is formed, but the impedance of this loop is high, the flowing search signal current level is low, and the other two phases 3b.

The display device H placed at 3C remains in the normal display state.Also, even if the display device is installed on the a phase, the search signal current does not reach a certain level or higher, so it is placed on the load side from the ground point T. The displayed display device 84 etc. remains in normal display mode.

In this way, from the search signal injection device F3 C:Z to the ground fault point T
After displaying the ground fault directly in the display A up to the point, the vehicle departs from the point where the full search signal injection device 8 was operated toward the load side. Then, if we sequentially search for the display devices H that are displaying a ground fault, we will find that the display device 1 that does not display a ground fault display is 1 of 4.
The point where the display wave δH3 during the previous ground fault display is placed,
Alternatively, it can be determined that the ground fault point T is located near the ground fault point.

In addition, in searching for the ground fault point, at the branch point α, the display device 12 installed on the branch line on one load side and the display device 1-13 installed on the branch line on the other load side are compared. Then, all you have to do is proceed along the branch line on the side where the display device is indicating the ground fault.

In addition, in the display device H which has displayed the ground fault display as described above, the timer 17 starts the return drive current to the coil after a predetermined time (for example, 3 to 4 hours) after the display unit 12 displays the ground fault display. (not shown) to return the display section 12 from the ground fault display to the normal display.

Next, the case of a short circuit accident will be explained.

When a short-circuit current of a certain level or more flows through the distribution line 3, the current transformer 10 outputs a transformation signal based on the short-circuit current, and the short-circuit detection sensor 19 displays a short-circuit detection on the display unit 12 in response to the transformation signal. Output a signal. Then, based on the short circuit detection signal, the display section 12 displays a short circuit as in the case of the ground fault detection. Then, after a predetermined period of time (3 to 4 hours) after the short circuit display state, this display section 12 displays the same signal as in the case of the ground fault display by applying the recovery drive current from the timer 17. The unit 12 is returned from the short-circuit display to the normal display.

In addition, in this embodiment, since a magnetic reversal display device is used in the display section, the display device H can have a simple structure, can be manufactured at low cost, and can be easily arranged in each section. The entire system also has the advantage of being low cost.

The present invention is not limited to the above-mentioned embodiment. For example, in the embodiment described above, the search signal injection device 8 manually injects the search signal current, but instead, when a ground fault occurs, An automatic search signal injection device may be used which automatically injects the search signal current at the same time as the sectional switch SS in the ground fault section locks open.

Generally speaking, in the above embodiment, a publicly known section switch SS is used, but it may be embodied in a section switch incorporating a search signal injection device therein. Also, in the above embodiment, a permanently installed search signal injection device was used, but instead of that, one injector! [It may also be an n-type search signal injection device.

Effects of the Invention As detailed above, this invention injects the search signal current from the search signal injection device in the ground fault fault section, so it is necessary to use a large number and expensive ZCT, V,
, There is no need to newly install an O capacitor, and there is an advantage that ground fault detection can be carried out at extremely low cost. It also has the great advantage of being able to identify ground fault phases.

In addition, since a display device that is activated by the search signal current is provided, it is practical in that the worker can easily identify the ground fault point without requiring time by simply making a primary tour from the search signal injection device to the load side. There are big advantages.

In this case, display devices, which need to be installed in large numbers at various locations on power distribution lines, do not require a function to send information about their display status to relay points such as substations, and therefore insulation from the ground does not need to be considered. A convenient configuration can be adopted, and the detection method of the present invention becomes extremely simple and inexpensive.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a front view of the search signal injection device mounted on a pillar, FIG. 2 is an electric circuit diagram of the social i motherboard claw device, FIG. Figure 4 is a power distribution diagram for explaining the operation, Figure 5 is a perspective view of the magnetic reversal display device,
Fig. 6 is an explanatory diagram showing the operation of the magnetic 4-magnetic reversal display device, Fig. 7 is a bottom view of the display section in the normal display state, and Fig. 8 is a bottom view of the display section in the ground fault display (short circuit display) state. It is. 1... Power transmission line, 2... Circuit breaker, 3... Distribution line, 4
...Zero-phase current transformer (7CT), 5...Grounding transformer If transformer (
GPT), 6... Directional ground fault relay, 7... Utility pole,
8... Search signal injection device, 10... Current transformer, 1
DESCRIPTION OF SYMBOLS 1...Gigaku detection sensor, 12...Display part, 19...
・Drive power supply, H-” ・Display device, SS... section switch. Patent applicant: Takamatsu Electric Manufacturing Co., Ltd.
Person Patent Attorney On 1) Hironobu Voluntary Procedural Amendment Written on November 21, 1980 Manabu Shiga, Commissioner of the Patent Office 2 Title of Invention Method for Detecting Ground Fault Points in Distribution Lines 3 Person Who Makes the Amendment Relationship to the Case: Patent Applicant Address: 1, Kamikobari, Inuyama Elementary School, Aichi Prefecture Name:
Takamatsu Electric Manufacturing Co., Ltd. (Name) Representative: Shigetsugube Takaoka 4, Agent Address: 2 Hatazume-cho, Gifu City, 500 Contents of Claims and Detailed Explanation of the Invention, Column 6, Supplement 1F of the Specification ( 1) Amend the statement in the claims column of the specification as shown in the attached sheet. 2) According to 1° on page 4, line 9 of the specification, the description of ``above'' is amended to ``tome 1-'\above up to the ground fault point'' by N town. Ru 1, Ra 9
．． He A. Kamo [2, Claims 1. The distribution line is divided with sectional switches, and when a ground fault occurs between the sectional switches, the substation repeats re-closing to open the sectional switches at both ends of the section where the ground fault occurs. In a power distribution system for detecting a ground fault fault section, a search signal injection device for injecting a search signal to each phase is coupled to one end of the section divided by the section switch,
A plurality of display devices are arranged in the section, which always display a normal display, and when the search signal is detected, change the normal display to a ground fault display based on the search signal, and the search signal is inputted from the search signal injection device. Injecting into the distribution line, as well as the distribution line.

Claims (1)

[Scope of Claims] 1. The distribution line is divided by section switches, and when a ground fault occurs between the section switches, reclosing is repeated on the substation side, so that both ends of the section where the ground fault occurs In a power distribution system that detects a ground fault section by opening a sectional switch, a search signal injection device for injecting a search signal to each phase is coupled to one end of the section divided by the sectional switch. ,
A plurality of display devices are disposed in the section, which always display a normal state display, and when the search signal is detected, change the normal state display to a ground fault display based on the search signal, and the search signal is inputted from the search signal injection device. A method for detecting a ground fault point in a power distribution line, characterized in that a search signal is injected into the power distribution line and flows through the power distribution line and the ground fault point to display a ground fault on the display device.