JPH02161366A - Discriminating method for accident point of substation - Google Patents

Abstract

PURPOSE:To quickly discriminate an accident point in a substation by impressing a test voltage from a secondary side of a measuring instrument use transformer and generating a withstand voltage test voltage in a bus, and discriminating whether an accident exists in the bus or not. CONSTITUTION:In an unmanned substation, for instance, it is assumed that an accident is generated in a bus 104. First of all, it is confirmed that a secondary breaker 102 of a transformer of a first bank B1 is tripped, and also, a section breaker 6 is cut off. Subsequently, in an accident point discriminating device 12, when a voltage is applied between an R phase of a secondary side of a measuring instrument use transformer 103 and a ground, a withstand voltage test voltage is generated between an R phase of a primary side of the transformer 103 and a ground, and it is impressed between an R phase of a bus 104 and a ground. Also, a voltage impressed between the R phase of the secondary side of the transformer 103 and a ground is boosted successively. In such a way, when an accident is not confirmed, a voltage is impressed successively and stepwide between an S phase of the secondary side of the transformer 103 and a ground, and furthermore, between a T phase and a ground.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a fault point determination method for a substation, which mainly determines the point of occurrence of a short circuit accident or a ground fault accident in an unmanned substation.

[Conventional technology] Conventionally, when an accident occurs at an unmanned substation like the one mentioned above, a test transformer is transported to the site by a transport vehicle, an insulation test is performed, and a withstand voltage test voltage is applied to determine the point of the accident. I was trying to do that.

[Problem to be solved by the invention] However, when determining the accident point using the method described above, it takes time to request dispatch at the site, dispatch time, etc., and it takes time to determine the accident. It takes a lot of time, for example, at an unmanned substation that requires 30 minutes to dispatch, it takes about 50 minutes to confirm the fault point.
The current situation is that the longer it takes to request dispatch, the longer it takes.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to quickly identify the accident point when an accident occurs at a substation.
The purpose is to provide an alternative method.

[Means for Solving the Problems] In order to solve the above problems, the method for identifying fault points in a substation according to the present invention includes a transformer secondary circuit breaker, a plurality of feeder circuit breakers, and at least one instrument transformer on the bus bar. When an accident occurs in a substation where instruments are connected in parallel, all circuit breakers connected to the bus bar are shut off, and then voltage is applied to the secondary side of the instrument transformer to perform a voltage withstand test on the bus bar side. The present invention is characterized in that a voltage is generated to determine the presence or absence of an accident on the bus bar side.

The present invention is characterized in that the voltage applied to the secondary side of the instrument transformer is a 4-phase voltage applied between the 111α order and the ground in each phase iIf.

The present invention provides voltages applied to the instrument transformer in stages 1ij, 7.
The feature is that the voltage is increased to perform a voltage proof test.

The present invention provides a substation in which the substation has two or more n-wires and is connected by a sectional circuit breaker in which the bus side of each adjacent bus bar is always in a disconnected state, 1. L
When a fault occurs on a line, the voltage applied to the secondary side of the instrument transformer of the faulty busbar is supplied via the station transformer connected to the non-faulty busbar. It is characterized by what it did.

Furthermore, the present invention is characterized in that voltage is applied to the secondary side of the instrument transformer based on a startup command from a remote control center.

[nMiHl] Apply voltage to the secondary 111 of the instrument transformer previously installed as described above, and apply a withstand voltage test voltage to the limb test area connected to the primary side of the instrument transformer. By doing this, there is no need to transport the transformer for voltage resistance tests.

Also, l! As a result of the voltage resistance test on the line side, it can be confirmed whether the bus bar is sound or whether the accident occurring is a ground fault or a short circuit.

In addition, by using a single-phase voltage as the voltage applied to the secondary side of the instrument transformer and performing a withstand voltage test on each phase in sequence, the load on the instrument transformer is reduced and the voltage is close to the operating voltage. A withstand voltage test is performed using voltage.

In addition, by performing a withstand voltage test by increasing the voltage applied to the secondary side of the instrument transformer in stages, the voltage applied to the secondary side of the instrument transformer can be increased even if the fault is a ground fault. The inflowing excessive current can be reduced.

Furthermore, in a substation that has two or more n-wires connected between each busbar side by a sectional circuit breaker that is normally in a disconnected state, the voltage applied to the secondary 11jlJ of the instrument transformer of the busbar where the fault occurred is Since the voltage is supplied via an in-station transformer connected to a bus bar in which no accident has occurred, the voltage can be obtained without providing a special power source.

[Example] Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is a single line diagram showing a substation implementing the method of the present invention.

In the figure, 101 to 301 are installed within the substation premises.
Step-down transformers from the first bank 81 to the third bank B3 each supply 77 kV to this substation.
The voltage is reduced to 6.6 (■). Transformer secondary circuit breakers 102-302 are connected to the secondary sides of these step-down transformers 701-301, respectively. Further, a plurality of feeder circuit breakers 110...-310... and at least one instrument transformer 103-303 are connected to the secondary sides of the transformer secondary circuit breakers 102-302, respectively. has been done.

Here, the secondary side of the transformer secondary circuit breakers 102 to 302 and each feeder 3I! The lines between the disconnectors 110... to 310... are defined as busbars 104 to 304 of each bank.

The bus bar 104 and the bus bar 204 are connected via a sectional circuit breaker 6, and the bus bar 104 and the bus bar 204 are connected via a sectional circuit breaker 6. ! 204 and the bus bar 304 are connected via a sectional circuit breaker 7. These classification 3! ! The disconnectors 6 and 7 are always in a disconnected state, and therefore each step-down transformer 101 is connected to each bus 104 to 304.
Power is supplied individually from ~301.

The instrument transformers 103 to 303 step down the bus voltage of 3KV to 110V, and are normally used for voltage monitoring or connected to a power meter (not shown). be.

109, 209 are in-house transformers, and each bus bar 104.20 is connected to the transformer secondary circuit breaker 102.202.
4 via circuit breakers 111.211.

Reference numeral 12 denotes a fault point determination device installed next to the substation, which is activated when an accident occurs and sends a predetermined signal to the instrument transformers 103 to 303 connected to the bus where the accident occurred. Therefore, a voltage is applied.

The accident point discriminating device 12 will be explained in detail below.

As shown in FIG. 2, the fault point determination device 12 includes a power input section 128, a test voltage forming section 12B, a test voltage output section 12C1, a signal receiving section 12D from each switchboard switch, etc. (not shown), Signal transmitting/receiving unit 1 with remote control station (not shown)
2E and a control section 12F consisting of a microcomputer.

The power input section 128 inputs in parallel the secondary side voltage stepped down to 200cm by the in-house transformers 109 and 209, and connects it to the test voltage forming section 12B via breakers 112Δa, 212Aa and power receiving switching contacts 112AI) and 212All, respectively. It is connected to the. In addition, this power input section 12
8, the voltage converter 1 is connected between the breaker 112Aa, 212Aa and the power receiving 9 switching contact 112Ab, 21281).
2Ac is connected. These breakers 112^a,
2128a, power reception switching contact 112Ab, lung 212, and voltage converter 128C are all connected to a control section 12F, which will be described later.

The test voltage forming part 12B has a voltage of 1.3,10°30 on the secondary side.
, an insulated lance 12Ba with 63.5V taps in 5 stages is provided. This insulation 1 to lance 12
Ba primary +l! 2 of the power supply section 12A is connected to I+.
The lines or respective input lines from the station transformers 109, 20! 11 are connected in parallel. Further, tap switching contacts 1281 to 12Bb5 are connected to each tap on the secondary side of this isolation transformer 12Ba, and these tap switching contacts 12Bt)1 to 12Bl+5 are connected to the common line 12B.
Connected to C.

An electromagnetic contact 12 is provided on the secondary side of the insulation 1 herance 12Ba.
Bd is connected, and a voltage converter 12Be and a current converter 12B[ are connected to the secondary side of this electromagnetic contact 12Bd. An isolation transformer 12Ba and tap switching contacts 12Bbl to 12Bl constitute this test voltage forming section 12B.
+5, the electromagnetic contact 12Bd, the voltage converter 12Bc, and the current converter 12B are also connected to the system (1 part 12), which will be described later.

The test voltage output section 12C includes output terminals 112Ca to 312Ca corresponding to each bank. The output lines connected to these output terminals 112Ca to 312Ca are branched into three from the output part of the test voltage forming section 12B, and each output terminal 112Ca to
One state side of each output line corresponding to 312Ca is further branched into three. In this way, each output terminal 11 is connected to the output line branched into three on one state side.
Corresponding to 2Ca to 312Ca, test phase switching contact 112
CI+, 112C3, 112C block, test phase switching contact 2
12CIt, 212C3, 212CT and test phase switching contacts 312CR, 312C3, 312C are connected, respectively. And test phase switching contacts 112CR, 21
The terminals of the output terminals to which 2CR and 312CR are connected are respectively connected to the R phase of the secondary side of the instrument transformers 103 to 303, and similarly, the test phase switching contact 112C
The terminal to which 3,212C3,312C3 is connected is the S phase, and the test phase switching contact 112CT, 212CT, 312C
The terminal to which T is connected is connected to the T phase. On the other hand, the terminals of the output terminals to which test 9) switching contacts are not connected are connected to the grounding wires of the instrument transformers 103 to 303, respectively. In addition, the above J exchange contact 112CR
~312CT and output terminal 112Ca ~312Ca
There is a voltage converter 12CC for measuring line voltage between
is connected.

The signal receiving unit 120 connects all the disconnectors connected to the fault bus in this unmanned substation, that is, the transformer secondary circuit breaker 102.
~302, Category 3! ! This is a part for inputting the open/close states of the circuit breakers 6, 7 and each feeder circuit breaker 110... to 310..., and all of these open/close states are input to the control unit 12F.

The signal transmitting/receiving unit 12E is a part that transmits and receives signals to and from a remote control center that remotely controls this unmanned substation, and receives an activation command from the remote control center for this fault point determination device 12, and also determines whether it is normal or an accident. It is equipped with an output section to send the results to a remote control center.

Further, the signal transmitting/receiving unit 12E is configured to send a signal to the remote control center indicating that activation is not possible when the II line that is considered to have caused an accident is a dormant bus.

Next, in the unmanned substation constructed as described in -1-,
A method for identifying an accident point, which is the gist of the present invention when an accident occurs, will be explained with reference to flowchart 1 in FIG. 3.

Suppose now that an accident occurs on Q line 104 in Yoshi.

First, a known protective relay (not shown) installed in the first bank B1 is activated, and the transformer secondary circuit breaker 102 of the first bank B1 is tripped.

In this way, it is confirmed that the transformer secondary circuit breaker 102 has tripped by step A in flowchart 1 of FIG.
at the remote control center.

Then, in step B, the remote control center receives this information, and in step B, each feeder circuit breaker 110 connected to this bus 104 is
. . and confirm that the sectional circuit breaker 6 is shut off.

Next, in step C, the remote control station confirms that the transformer secondary circuit breaker 102 has tripped and interrupted the line, and in step D, issues a device activation command to the fault point determination device 12 in the unmanned substation. .

This device activation command is sent to the control unit 12F via the activation signal input terminal of the signal transmitting/receiving unit 12 of the accident point discriminating device 12.

When the control unit 12 receives the activation command, it confirms via the voltage converter 12Cc that no voltage is generated on the secondary side of the instrument transformer 103 in step E, and also shuts off the secondary circuit of the transformer. 102, the section circuit breaker 6, the feeder circuit breaker 110, etc. are all open (starting conditions are met via the signal receiving unit 12D). A withstand voltage test is performed on the busbar 104 section. This will be explained in detail below.

The control unit 12 [is the voltage converter 1 to the power input unit 12
Two station transformers 10 are activated by the signal input from 28c.
9. Confirm that one of the terminals 209 is generating a secondary voltage of 200V, and close the power receiving switching contacts 112Ab and 212Ab on the side generating the voltage. In this case, the bus bar 104 of the first bank B1 is connected to the transformer secondary circuit breaker 10
Since there is a power outage due to the two-month rip, of course no voltage is generated on the secondary side of the station transformer 109, and the control unit 12F closes the power reception switching contact 212.

As described above, voltage is supplied from the power input section 12A to the primary side of the isolation transformer 12Ba of the test voltage forming section 12B.

When the voltage is supplied to the primary side of the isolation transformer 12Ba in this way, the control section 12F controls the isolation transformer 12B.
Among the tap switching contacts connected to each tap on the secondary side of a, the tap switching contact 12Bbl connected to the tap that outputs 1■ is left blank, and among the test phase switching contacts of the test voltage output section 12C, Test phase switching contact 112C of output terminal 112Ca corresponding to bus 104, which is the bus where the accident occurred
Close R. Next, the control section 12F controls the test voltage forming section 1.
By closing the electromagnetic contact 12Bd of 2B, a voltage of 1 is applied between the R phase of the secondary side of the instrument transformer 103 and the ground via the output terminal 112Ca. Therefore, a withstand voltage test voltage of approximately GOV is generated between the R phase on the negative side and the ground,
This is applied between the R phase of bus bar 104 and the ground.

If the occurrence of an accident is not confirmed by the above-mentioned 130V withstand voltage test voltage, the control unit 12 opens the electromagnetic contact 12Bd, then opens the tap switching contact 12Bbl on the secondary side of the isolation transformer 128a, and outputs 3V instead. Close the tap switching contact 12Bb2 to which the tap is connected, and then close the electromagnetic contact 12Bd again.By doing this, a voltage of 3■ is applied between the 1z phase on the secondary side of the instrument transformer 103 and the ground. Therefore, a withstand voltage test voltage of approximately 180 .mu.

Below, unless the occurrence of an accident is confirmed, the tap changeover contact formed by r71 will be changed to the tap changeover contact 12Bb3.12BI+.
4゜12Bl15, and the voltage applied between the R phase of the secondary side of the instrument transformer 103 and the ground is changed to 10.
V.

Sequentially increase the voltage to 30V and G3.5V. As a result, withstand voltage test voltages of GOOV, 1800V, and 3810V are generated between the R phase of the instrument transformer III+103- and the ground. The application time of each withstand voltage test voltage controlled by the control unit 121 is 10 seconds for the 3810V withstand voltage test voltage, and 5 seconds for the other withstand voltage test voltages.

By the way, the withstand voltage test voltage of 3810V is the voltage to ground when the operating voltage is the line voltage GGOOV, and it is originally desirable to perform the withstand voltage test at this operating voltage as much as possible.
However, if the accident is a ground fault, an excessive current will flow, so in order to protect the test circuit, especially the instrument transformers 103 to 303, the test voltage is gradually reduced from an extremely low voltage as described above. By increasing the current, the inflow of excessive current is suppressed.

If no fault is confirmed as a result of applying voltage in stages between the R phase and the ground wire on the secondary side of instrument transformer 103 as described above, then The presence or absence of an accident is confirmed by applying voltage in stages between the S phase and the ground wire in the same manner. If no accident is confirmed even after this, the instrument transformer 1
03 Apply voltage stepwise between the 1' phase on the secondary side and the ground wire to check for any faults.

Next, when an accident is confirmed, a method for determining whether the accident is a ground assembly accident or a short circuit accident will be explained.

As shown in FIG. 5A, when no fault has occurred on the bus bar 104 and the above-mentioned withstand voltage test voltage is applied, the ground capacitance C of the 1; As a result, as shown in FIG. 5B, a predetermined inflow current 11 flows into the R phase to which the test voltage is applied to the secondary (jjll) of the instrument transformer 103.
A predetermined line voltage VB-11 between the R phase and the S phase. R phase and 'r
V@-( is induced between the phases.

These inflow currents i and line induced voltages VB-6, V, -
6 is determined by the state of the load caused by the station transformer 109 because all other loads connected to the bus 104 other than the station transformer 109 are cut off.

Figure 4A shows the meter transformer 103 when the load of the station transformer is taken as a parameter and 63.5 mm is applied to the secondary side of the instrument transformer 103 to generate a withstand voltage test voltage of 3810 V on the primary side. The figure shows the inflow current to the secondary side of the transformer 103.

On the other hand, in Fig. 4B, the load of the station transformer is taken as a parameter,
63.5 on the secondary side of instrument transformer 103 when in good condition.
It shows the induced voltage between each line on the secondary side of the instrument transformer when V is applied to generate a withstand voltage test voltage of 3810 V on the primary side.

The load connected to the station transformer varies greatly depending on the season and time, and there are cases where the load is disconnected manually or automatically in the event of an accident. The inflow current and line induced voltage are calculated based on the estimated capacity 1 of the station transformer. Therefore, it is necessary to estimate the load per cycle at the time of device startup, which is the basis for settling, and to store the inflow current and line-induced voltage in the control unit 12F corresponding to the load.

As shown in Figure 6A, the accident that occurred on the busbar 104 caused
In the case of a phase ground fault, a much larger inflow current i flows through the secondary R phase of the instrument transformer 103 than when it is healthy, as shown in FIG. 6B. Therefore, if the upper limit value of the inflow current at the estimated load per unit by the station transformer 109 shown in FIG. 4A is stored in the control unit 12, the current converter 128 of the test voltage forming unit
By monitoring the R-phase inflow current on the secondary side of the instrument transformer 103 by r, when the control unit 12F measures an inflow current exceeding the upper limit value via the current converter 12B, this control Part 12" indicates that a ground fault has occurred in the R phase of the bus 104. For example, in Figure 4A, if the estimated load is 3KW, the upper limit of the inflow current is 8A. By this, it is possible to determine the excessive current when a ground fault occurs.Of course, the S of the bus 104
Even if a ground fault occurs in the phase and 'r phase, a test voltage is applied to the S phase and 'r phase on the secondary side of the instrument transformer 103, and the current converter 12B' By monitoring the S-phase or T-phase current on the secondary side of 103, it is possible to detect the occurrence of an accident.

Next, as shown in FIG. 7A, a case will be described in which the fault that occurs on the bus bar 104 is a short circuit fault between the R phase and the S phase. In this case, since the R phase and S phase on the secondary side of the instrument transformer 103 are short-circuited, even if a test voltage is applied between the R phase on the secondary side of the instrument transformer 103 and the ground, the R phase Almost no voltage is induced between the and S phase lines, therefore, the above 4th B
If the lower limit value of the line induced voltage at the estimated load per unit by the station transformer 109 in the figure is stored in the control unit 12F, the voltage converter 1 of the test voltage output unit 12C
By monitoring the line voltages of the R phase and S phase on the secondary side of the instrument transformer 103 using 2Cc, the line voltage below the lower limit value is transmitted to the control unit 12 via the voltage converter 12Cc.
When R of the bus 104 is measured, this control unit 12F
It can be determined that a short circuit accident has occurred between the phase and the S phase. For example, in Figure 4B, if the estimated load is 3KW, the lower limit of the line-to-line induced voltage is set to 9■, so that if the line-to-line induced voltage is less than 9■, a short circuit accident may occur. can be detected. Of course, bus line 1
Even if a short-circuit accident occurs between the 'r phase and R phase of instrument transformer 103, by monitoring the line voltage between the T phase and R phase on the secondary side of instrument transformer 103, the problem can be solved in the same way as above. You can confirm a short circuit, and even if a short circuit occurs between the S phase and T phase of the bus 104, you can test between the S phase and the ground wire or between the T phase and the ground wire on the secondary side of the instrument transformer 103. By monitoring the line voltage induced between the S phase and 'r phase on the secondary side while the voltage is applied, the control unit 12F
It can be detected in

The results of the withstand voltage test conducted by applying the test voltage to each phase in stages as described above are as follows:
In step G, the signal is sent to the remote control center via the signal transmitting/receiving section 12.

In other words, if a ground fault or short circuit accident is confirmed in the above-mentioned withstand voltage test, and an accident display is issued to the remote control center (if the output of step G is N), the remote control center will perform step l-1. An accident display indicating the details of the accident is received, and based on the result, on-site repair work is started in Step I.

In addition, in the remote control station that has received the normal signal from the fault point determination device 12 in step H2, first in step P, the step-down transformer 201 of the second bank B2 takes on the load connected to the bus bar 104 of the first bank B1. Check to see if you have enough free space.

In step P, if it is confirmed that there is a margin in the step-down transformer 201, the remote control center confirms in step Q that the transformer secondary circuit breaker 102 of the first bank B1 is disconnected, and then the first bank A command is sent to close the sectional circuit breaker 6 that connects the bus bar 104 of B1 and the bus bar 204 of the second bank B2. As a result, power is supplied to the bus 104 from the step-down transformer 201, and in step R, each feeder circuit breaker 110 connected to this i & line 104
. . are supplied in an amount commensurate with the margin of the step-down voltage 1 to the lance 201, power is supplied to the loads connected to these feeder circuit breakers 110.

As described above, when it is confirmed that the bus bar 104 is healthy, if the step-down transformer 201 of the second bank B2 has a margin, the load on the bus bar 104 can be quickly reduced by connecting the bus bar 204 and the bus bar 104. Can supply electricity.

After quickly eliminating the power outage for the load on the bus 104 in this way, the remote control center performs the following steps in step S.
Disconnector 101 of first bank B1 and transformer secondary breaker 10
In order to prevent accidental injection of 2.2, the injection lock was applied to these, and the accident was investigated at the site afterwards.
Repair work will begin.

It goes without saying that even if the 1-year line where the accident occurred is on another bus line, the accident point can be determined in exactly the same way.
The withstand voltage test performed in step F does not have to be carried out exactly as described above.
~303 The number of stages of voltage applied to the secondary side and each voltage value can be variously changed in design depending on the load capacity of the instrument transformers 103~303.

In addition, the voltage-resistant busbars can be applied not only to G and GKV busbars but also to 22 and V busbars.

[Effects of the Invention] As is clear from the above explanation, according to the fault point determination method for a substation according to the present invention, a test voltage is applied from the secondary side of an instrument transformer to Since the withstand voltage test voltage can be applied to the substation, the withstand voltage test can be performed extremely quickly and the fault point within the substation can be determined.

[Brief explanation of the drawing]

Fig. 1 is a single-line diagram of a substation implementing the present invention, Fig. 2 is a configuration diagram that does not show the main parts of Fig. 1, and Fig. 3 is a flowchart 1 diagram showing an embodiment of the present invention. Figure 4A is a graph showing the inflow current value corresponding to the load by the station transformer in healthy conditions, which determines the set value for ground faults, and Figure 4B shows the load by the station transformer in healthy conditions, which determines the set value for short circuit accidents. A graph showing the line-to-line induced voltage value corresponding to the 5th Atg is a circuit diagram showing the current distribution when the area under test is healthy.
Figure 5B is a vector diagram of the current and voltage in Figure 5A, Figure 6A is a circuit diagram showing the current distribution when there is a ground fault in the area under test, and Figure 6B is a vector diagram of the current and voltage in Figure 6A. 7A is a circuit diagram showing the current distribution when there is a short-circuit accident in the test area, and FIG. 7B is a vector diagram of the current and voltage in FIG. 7A.

Claims (5)

[Claims] (1) When an accident occurs in a substation where a transformer secondary circuit breaker, multiple feeder circuit breakers, and at least one instrument transformer are connected in parallel to the bus, all circuit breakers connected to the bus are disconnected. An accident at a substation characterized in that the circuit is shut off, and then a voltage is applied to the secondary side of the instrument transformer to generate a withstand voltage test voltage on the bus bar to determine whether or not there is an accident on the bus bar. Point discrimination method. (2) The method for determining faults in a substation according to claim 1, characterized in that the voltage applied to the secondary side of the instrument transformer is a single-phase voltage that is sequentially applied between each phase and ground. (3) The method for determining a fault point in a substation according to claim 1 or 2, characterized in that the voltage applied to the instrument transformer is stepped up to perform a withstand voltage test. (4) The substation has two or more busbars, and each adjacent busbar is connected by a sectional circuit breaker that is normally disconnected, and an accident has occurred in one busbar. When the fault occurs, the voltage applied to the secondary side of the instrument transformer of the bus bar where the fault has occurred is supplied via an in-station transformer connected to the bus bar where the fault has not occurred. A fault point determination method for a substation according to claim 1, 2 or 3. (5) The substation according to claim 1, 2, 3, or 4, wherein the voltage is applied to the secondary side of the instrument transformer based on a startup command from a remote control center. Accident point determination method.