JPH07270473A - Diagnostic method and device for bus bar accident - Google Patents

Abstract

PURPOSE:To provide a bus-bar accident diagnostic device having the capability of quickly and easily diagnosing an accident, and preventing such a danger of occurrence that an overcurrent flows. CONSTITUTION:When an accident such as grounding and shortcircuit occurs in an electric power system at a substation or the like for power distribution, an electrode 23 is connected to a bus-bar. Also, insulation resistance between the bus-bar and the earth is measured with a resistance meter 31 laid between the electrode 23 and the earth. Then, the possibility of re-feeding power to the bus-bar is judged with a control device 33 on the basis of the insulation resistance measured with the meter 31.

Description

Detailed Description of the Invention

[0001]

[Industrial application] This invention, in a distribution substation, etc., in the event of an accident such as a ground fault or a short circuit in the power system including the power transformer, whether the insulation can be recovered and re-transmitted to the busbar. The present invention relates to a bus line accident diagnosis device for diagnosing.

[0002]

2. Description of the Related Art Conventionally, in a distribution substation, for example, as shown in FIG. 6, a power transformer 42 is installed in the premises of a substation 41, and the power of a high voltage bus bar 43 is stepped down to a predetermined low voltage. And is supplied to the distribution bus 44. A plurality of disconnectors 45 and circuit breakers 46 are connected to the primary side of the power transformer 42, and a circuit breaker 47 is connected to the secondary side. Then, in the premises of the distribution substation 41, when an accident such as a ground fault, a short circuit, or a device failure occurs in the power system including the power transformer 42, the primary side disconnector 45 and the secondary side disconnector The container 47 and the like are opened, and power transmission to the power distribution bus 44 is stopped.

When an accident occurs in this way, conventionally, in principle, a maintenance worker is urgently dispatched to the site to conduct a patrol inspection to investigate the location of the accident and to judge the accident situation. After that, the work of removing the accident point and restoration is carried out to restore the trial transmission and power supply. However, this conventional method has a problem in that maintenance and inspection work is troublesome because maintenance personnel perform an artificial inspection and inspection at the site, and it takes time before re-transmission. For this reason, if the operator of the substation relied on his skill and intuition to judge that it was safe, he or she might re-transmit the power immediately after the accident. There was probably a risk of another accident.

In order to deal with the above-mentioned problems, the following diagnostic method has been conventionally used. The first method is to supply a voltage in the reverse direction from the secondary side to the primary side of the power transformer 42 via the distribution bus 44 by switching from another substation, and to supply a predetermined voltage to the substation 41. Is applied to diagnose whether to withstand re-transmission. Also, the second method is
A power supply 48 for the premises such as a battery is used to supply a voltage in the reverse direction from the secondary side of the power supply transformer 49 to the primary side.
A predetermined voltage is applied to the substation 41 for diagnosis.

[0005]

However, the first conventional diagnostic method has the following problems. (A) Switching for reverse power transmission is troublesome. That is, since this switching is performed in another substation or the like, the switching is large and troublesome and time-consuming. (B) If the failure continues, the accident will reoccur due to reverse power transmission. (C) An excessive current may flow through the power transformer 42, which may cause secondary damage to the device, which may increase the accident.

In the second conventional diagnostic method,
There were the following problems. (A) It is necessary to increase the capacity and take measures against overcurrent in the power supply device 48 for the premises and the transformer 49 for the power supply, which makes the structure complicated and increases the cost. (B) If the failure continues, the accident not only reoccurs as described above, but also the amount of electricity stored in the power supply device 48 is drastically reduced to cause a temporary drop in voltage, which may cause other troubles such as a control panel. It may not be used as an emergency power source for equipment.

Further, the conventional first and second diagnostic methods have the following common problems. (A) No internal failure of the transformer 42 or the like can be confirmed. (B) Since voltage is applied from the secondary side of the transformer 42,
The equipment in the substation 41 may be damaged, resulting in a secondary disaster.

The present invention has been made by paying attention to the problems existing in such conventional techniques. The purpose is to reduce the power capacity used during accident diagnosis and prevent the possibility of overcurrent even if the bus accident continues, thus preventing secondary accidents. To provide a diagnostic method and a diagnostic device. Another object of the present invention is to provide a busbar accident diagnosing method and a diagnosing device which can easily and quickly determine the accident state and can prevent the influence on other equipment unrelated to the accident. .

[0009]

In order to achieve the above object, in the invention of a busbar accident diagnosis method according to claim 1, when an accident occurs, the insulation resistance between the busbar and the ground is measured, The possibility of re-power transmission to the bus bar is determined based on the measured resistance value.

According to the invention of claim 2, in the invention of claim 1, the measured value of the insulation resistance is compared with a judgment reference value. According to a third aspect of the invention, in the first aspect of the invention, the insulation resistance measuring electrode connected to the bus bar is separated from the bus bar before the insulation resistance between the bus bar and the ground is measured. , To measure the insulation resistance between the electrode and ground.

In the invention of the busbar accident diagnosing device according to the fourth aspect, an electrode connected to the busbar when an accident occurs and an insulation resistance between the busbar and the ground are connected between the electrode and the ground. A resistance measuring device to be measured and a control means for judging the possibility of re-power transmission to the bus bar based on the value of the insulation resistance measured by the resistance measuring device.

According to the invention of claim 5, in the invention of claim 4, there is provided a mechanism for discharging the electric charge of the portion measured prior to the measurement of the insulation resistance by the contact of the auxiliary electrode to the portion. .

According to a sixth aspect of the invention, in the fourth aspect of the invention, the control means is an insulation resistance. At least one criterion value is provided to determine the possibility of re-power transmission to the bus based on the measured value.

[0014]

According to the first aspect of the present invention, when an accident such as a ground fault or a short circuit occurs in a power system such as a distribution substation, the insulation resistance of the busbar is measured. Then, the possibility of re-power transmission to the bus bar is determined based on the measured insulation resistance value.

In the second aspect, after the insulation resistance of the bus bar is measured, the possibility of re-power transmission to the bus bar is determined based on the comparison between the measured value and the determination reference value. According to the third aspect, the insulation resistance between the electrode and the ground is measured prior to measuring the insulation resistance of the bus bar.

In the fourth aspect, when an accident such as a ground fault or a short circuit occurs in a power system such as a distribution substation, the electrodes are connected to the bus bar. In this state, the insulation resistance of the bus bar is measured by the resistance measuring device connected between the electrode and the ground. Then, based on the value of the insulation resistance measured by the resistance measuring device, the control means determines the possibility of re-power transmission to the bus bar.

Further, according to the present invention, the auxiliary electrode is brought into contact with the portion to be measured before the insulation resistance of the bus bar is measured, and the electric charge in the portion is discharged. Further, in claim 6, after the insulation resistance of the bus bar is measured, it is determined whether or not there is a possibility of re-power transmission to the bus bar based on a comparison between the measured value and a determination reference value provided in the control means. To be done.

[0018]

[Embodiment] An embodiment of a busbar accident diagnosing device in a distribution substation embodying the present invention will be described below with reference to FIGS. 1 to 5. As shown in FIG. 2, a power transformer 1
Is installed in the premises of the distribution substation 2, and the power of the high voltage bus bar 3 is stepped down to a predetermined low voltage by this transformer 1 and supplied to the power distribution bus 4. The plurality of disconnectors 5, 6, 7, 8 and the breaker 9 are connected to the primary side of the power transformer 1, and by opening and closing these disconnectors 5-8 and the breaker 9, the high voltage bus 3
The power supply from the transformer to the primary side of the transformer 1 is controlled. The circuit breaker 10 is connected to the secondary side of the power transformer 1, and opening and closing of the circuit breaker 10 controls power supply from the secondary side of the transformer 1 to the power distribution bus 4.

Devices such as the transformer 1 and the disconnecting switches 5, 6, 7 and 8 are provided with sensors (not shown) for detecting the states of those devices, and a plurality of electric wires in the substation 2 are provided. A sensor (not shown) for detecting voltage / current is provided at the location. Then, in the premises of the distribution substation 2, when an equipment failure or an accident such as a ground fault or a short circuit occurs in the power system including the power transformer 1, the primary side disconnector is based on the detection signal from the sensor. 5 and the secondary-side circuit breaker 10 are opened, the premises of the substation 2 is cut off, and the power transmission to the distribution bus 4 is stopped.

The busbar accident diagnosing device 11 is arranged near each of the secondary side disconnectors 8 and is connected to the high voltage busbar 3 when an accident occurs. The insulation resistance between the high voltage busbar 3 and the ground is measured by the busbar accident diagnostic device 11.
The possibility of re-power transmission to the bus bar 3 is determined based on the measured value.

Therefore, the busbar accident diagnosing device 11 and its related structure will be described in detail. As shown in FIGS. 1 and 3, the pair of supporting insulators 12 in the disconnector 8 are arranged on the supporting plate 13 at predetermined intervals. It is erected, and the fixed electrode 14 is attached to the upper end thereof. The rotary insulator 15 is rotatably supported on the support plate 13 between the support insulators 12,
The movable electrode 16 is attached to its upper end. By the rotation of the rotary insulator 15, the movable electrode 16 comes into contact with and separates from the fixed electrode 14, and the electric path is opened and closed.

The measuring contact plate 17 is connected and fixed to the fixed electrode 14 on one supporting insulator 12 of the disconnector 8.
A pinching contact portion 18 and an auxiliary contact portion 19 are formed at the tip thereof. The rotating shaft 20 is attached to one side of the support plate 13 by the mounting plate 2
It is rotatably supported via 1 and is grounded via a support plate 13 or the like. The motor 22 is connected to the rotary shaft 20 and rotates the rotary shaft 20 by a predetermined angle when an accident occurs.

The measuring electrode 23 is attached to the rotary shaft 20 via an insulator 24 so that the rotary shaft 20 can be used when an accident occurs.
With the rotation of, the pinching contact is made with the pinching contact part 18 of the measuring contact plate 17. The auxiliary electrode 25 is attached to the rotary shaft 20 adjacent to the measuring electrode 23, and the rotary shaft 2 is attached when an accident occurs.
With the rotation of 0, the auxiliary electrode 25 is moved to the auxiliary contact portion 1 before the measuring electrode 23 comes into contact with the insertion contact portion 18.
9 is touched. Then, the electric charge staying in the electric path in this contact state is released to the ground via the auxiliary electrode 25, the rotating shaft 20, and the like.

As shown in FIG. 1, the driving device 26 is connected to the motor 22 and receives power supply from the indoor power supply device 27 to drive and control the motor 22. Various sensors 28 including the above-described sensors are arranged inside and outside the distribution substation 2 and output various detection signals to the drive device 26. The command device 29 is arranged indoors or outdoors of the distribution substation 2 and outputs a drive command signal to the drive device 26 when an accident such as a ground fault or a short circuit occurs in the power system of the substation 2.

The measurement / diagnosis circuit 30 is connected and arranged between the measuring electrode 23 and the ground, and comprises a resistance measuring section 31, a power source section 32 and a control section 33. The resistance measuring unit 31 is composed of a resistance measuring device such as a megger connected between the measuring electrode 23 and the ground, and the measuring electrode 23 is connected to the measuring contact plate 17.
The insulation resistance of the bus bar 3 is measured in a state of being sandwiched and contacted by the sandwiching contact portion 18 of FIG. Further, the resistance measuring unit 31 measures the insulation resistance of the insulator 24 of the measurement electrode 23 in advance in a state where the measurement electrode 23 is separated from the insertion contact portion 18 before the measurement of the insulation resistance of the bus bar 3. This insulation resistance measurement is
The insulator 24 is sandwiched in the vicinity of the insulator 24.

The power supply unit 32 is composed of a storage battery which is charged by electric power supplied from the indoor power supply device 27 and applies a voltage for resistance measurement when the insulation resistance is measured by the resistance measurement unit 31. A control unit 33 including a CPU (Central Processing Unit) and a memory constitutes a control device as control means,
A program for controlling the entire measurement / diagnosis circuit 30,
The determination reference value as shown in FIG. 5 is stored. Further, when an accident occurs, the control unit 33 receives the detection signals from the various sensors 28 and the command signal from the command device 29, and causes the resistance measuring unit 31 to measure the insulation resistance of the bus bar 3, and the measured value and the judgment reference value. The possibility of re-transmission is determined based on the comparison with.

Next, the operation of the bus-bar accident diagnosing device configured as described above will be described with reference to the flow chart shown in FIG. By the way, when an accident such as a ground fault occurs in the premises of the distribution substation 2 and a power failure occurs in the premises of the substation 2, the command device 2
A command signal for instructing busbar accident diagnosis is output from 9 to the drive unit 26 and the control unit 33. This command signal may be configured to be automatically performed by receiving output signals from various sensors 28 or may be configured to be manually output.

Based on the detection signals from the various sensors 28, the drive unit 26 determines from the above-mentioned command signal whether or not the automatic periodic inspection is being performed, and if the inspection is in progress, the flow ends. It waits to do (step S1).

Next, the drive unit 26 determines whether or not the interlock condition is satisfied, and if the condition is not satisfied, it is determined that measurement is impossible and the diagnostic operation is ended (steps S2 to S3). This interlock condition applies to substation 2
Whether or not each of the disconnecting switches 5 to 8 and the circuit breakers 9 and 10 are opened, whether or not the measuring electrode 23 is at a predetermined standby position, and whether or not the bus bar voltage is below a predetermined value. Is.

When the interlock condition is satisfied, the control unit 33 of the measurement / diagnosis circuit 30 insulates the measurement electrode 23 in the standby state in which the measurement electrode 23 is separated from the pinching contact portion 18. The insulation resistance of the insulator 24 is measured. If the insulation resistance is below a predetermined value (for example, 2000 MΩ) due to contamination of the insulator 24 or the like, the resistance measuring unit 31 is out of order, or the insulation of the insulator 24 is insufficient or short-circuited, and measurement is impossible. The diagnostic operation is ended (steps S4 and S3).

On the other hand, when the insulation of the insulator 24 is sufficiently ensured and measurement is possible, the drive unit 26 is set to the motor 2
2 is driven to rotate the rotary shaft 20, and the measurement electrode 23 is brought into contact with the insertion contact portion 18 of the measurement contact plate 17 in an interposition (step S5). At this time, the auxiliary electrode 25 is brought into contact with the auxiliary contact portion 19 before the measuring electrode 23 comes into contact with the sandwiching contact portion 18. As a result, the electric charge staying in the electric path is escaped from the auxiliary contact portion 19 to the ground via the auxiliary electrode 25, the rotating shaft 20 and the like, and damage to the measurement / diagnosis circuit 30 and the like is prevented.

After that, the driving device 26 confirms whether or not the measuring electrode 23 is in the pinching contact with the pinching contact portion 18 by a sensor (a sensor for detecting the rotating position of the measuring electrode 23), and the contact is made. If not, the diagnosis operation is terminated as a malfunction (steps S6 to S7). Further, when they are in contact with each other, the control unit 33 operates the resistance measuring unit 31 to measure the insulation resistance between the bus bar 3 and the ground via the measuring electrode 23 (step S8). Then, the control unit 33 changes the measured value of the insulation resistance from the resistance measuring unit 31 to
The possibility of re-power transmission is determined by comparing with the determination reference value in the memory (step S9).

That is, in the memory of the control unit 33, as shown in FIG. 5, two judgment reference values P1 and P2 are set corresponding to the measured values of the insulation resistance. The first determination reference value P1 (for example, 10 MΩ) indicates a boundary point between prohibition and caution of re-transmission, and the second determination reference value P2 (for example, 1000 MΩ) indicates a boundary point between caution and possible re-transmission. Has been done. Therefore, the determination result according to the determination reference values P1 and P2 is output from the control unit 33 as prohibition, caution, or possible re-transmission. This output is
It is displayed on the display (not shown) of the command device 29.

After that, the driving device 26 drives the motor 22 to rotate the rotating shaft 20 in the opposite direction, and separates the measuring electrode 23 from the inserting contact portion 18 (step S10). Then, the drive device 26 confirms whether or not the measuring electrode 23 has been returned to the original position, and if it has been returned to the original position, completes all diagnostic operations (step S11). If foreign matter or the like has entered the movable part and the measurement electrode 23 has not been returned to its original position, the diagnosis operation is terminated as an operation failure (steps S11 and S7).

As described above, in the busbar accident diagnosing device of this embodiment, after the accident, by measuring the insulation resistance, it is possible to quickly judge whether or not the power can be retransmitted. For this reason, it is not necessary to perform time-consuming work such as checking the situation at the site by the security staff to determine whether or not to approve re-transmission, and labor for reverse power transmission. By doing so, it is possible to minimize the effect of power outage and secure the time until complete recovery.

In addition, in the busbar accident diagnosing device of this embodiment, the measuring electrode 23 is connected to the busbar 3, and the resistance measuring section 31 measures the insulation resistance of the busbar 3. Therefore, unlike the case where current is sent back from the power supply device to the transformer, it is possible to reduce the power supply capacity used during accident diagnosis and prevent the risk of overcurrent flowing in the substation, resulting in equipment damage. It can prevent secondary disasters such as.

Further, in the busbar accident diagnosing device of this embodiment, in a state where the measuring electrode 23 is separated from the busbar 3,
The resistance measuring unit 31 measures the insulation resistance of the insulator 24 of the measuring electrode 23 in advance as a so-called pre-measurement. Therefore, the failure of the resistance measuring unit 31 and the insulation failure of the insulator 24 are detected, the measurement is not performed in the abnormal state, and the measurement is performed only in the normal state, so that the accurate measurement can always be performed. Moreover, it is possible to prevent damage to the measuring device and the like.

Further, in the bus line accident diagnosing device of this embodiment, two judgment reference values P are stored in the memory of the control unit 33.
1 and P2 are set. Therefore, the possibility of re-power transmission can be accurately determined from the measured value of the insulation resistance based on the determination reference values P1 and P2.

The present invention is not limited to the above embodiment, and may be embodied by changing the configuration as follows, for example. (A) To set one or three or more determination reference values in the memory of the control unit 33. (B) The measurement electrode 23 should be provided in a place other than the disconnector.

By the way, in this specification, the busbar includes all the power lines in the substation. The substation includes any substation such as a power transmission or distribution substation, an indoor or outdoor substation, a constant monitoring control or an intermittent monitoring control substation.

[0041]

Since the present invention is configured as described above, it has the following excellent effects. According to the invention described in claims 1 and 4, since it is the method of measuring the insulation resistance of the bus bar, the accident diagnosis can be performed quickly and accurately, and the power supply capacity used during the accident diagnosis can be reduced. In addition, it is possible to prevent the possibility of overcurrent and prevent a secondary disaster due to equipment damage.

According to the third and fifth aspects of the invention, the insulation resistance of the bus bar can be accurately measured by the pre-measurement. Further, according to the invention described in claims 2 and 6, after measuring the insulation resistance, it is possible to accurately determine whether or not there is a possibility of re-power transmission to the bus bar based on the determination reference value from the measured value. it can.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a busbar accident diagnosis device in a distribution substation embodying the present invention.

FIG. 2 is a wiring diagram showing a power system of a distribution substation including the bus line fault diagnosis device.

FIG. 3 is a partial perspective view showing the voltage applying mechanism in the busbar accident diagnosing device.

FIG. 4 is a flowchart for explaining the operation of the bus line accident diagnosis device.

FIG. 5 is an explanatory diagram showing a determination output map stored in a control unit of the bus line accident diagnosis device.

FIG. 6 is a wiring diagram illustrating a power system of a distribution substation in order to explain a conventional busbar accident diagnosis method in the distribution substation.

[Explanation of symbols]

1 ... Power transformer, 2 ... Distribution substation, 3 ... High voltage busbar,
8 ... Primary side disconnecting switch, 11 ... Busbar accident diagnosing device, 17 ... Contact plate for measurement, 18 ... Insert contact part, 23 ... Electrode for measurement, 2
6 ... Driving device, 30 ... Measurement / diagnosis circuit, 31 ... Resistance measuring part constituting resistance measuring device, 32 ... Power source part, 33 ... Control part constituting control device as control means, P1 ... Judgment standard,
P2 ... Criteria.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Genzo Kimura 2-56 Sudamachi, Mizuho-ku, Nagoya

Claims (6)

[Claims] 1. A bus-bar accident diagnosis method for measuring insulation resistance between a bus-bar and ground when an accident occurs and determining the possibility of re-power transmission to the bus-bar based on the measured resistance value. 2. The busbar accident diagnosis method according to claim 1, wherein the measured value of the insulation resistance is compared with a judgment reference value. 3. An insulation resistance between an electrode and the ground in a state where an insulation resistance measuring electrode connected to the bus is separated from the bus prior to measuring the insulation resistance between the bus and the ground. The busbar accident diagnosis method according to claim 1, wherein 4. An electrode connected to the bus bar when an accident occurs,
A resistance measuring instrument that is connected between the electrode and ground and measures the insulation resistance between the bus bar and the ground, and based on the value of the insulation resistance measured by the resistance measuring device, A bus-bar accident diagnosing device having a control means for judging the possibility. 5. The bus voltage diagnosing device according to claim 4, further comprising a mechanism for discharging the electric charge of the portion measured prior to the measurement of the insulation resistance by the contact of the auxiliary electrode to the portion. 6. The busbar accident diagnosing device according to claim 4, wherein the control means includes at least one judgment reference value for judging the possibility of re-power transmission to the busbar based on the measured value of the insulation resistance. .