JPH02142307A - Gas insulated electrical equipment - Google Patents

Abstract

PURPOSE:To detect abnormality and locate fault points reliably by providing inner pressure detectors for a plurality of gas sections and a means for operating inner pressure rise then determining that a fault point exists in the section having minimum deviation between measured inner pressure and operated inner pressure. CONSTITUTION:A metering potential transformer PT for detecting the bus voltage, metering current transformers CT1-CTk for a plurality of I/O lines, inner pressure detectors S1-Sn for a plurality of gas sections and a CPU1 for performing various operations are provided. Energy and pressure rise are operated for all sections, then it is determined that a fault point exists in the section having minimum difference between measured inner pressure and operated inner pressure thus detecting abnormality and locating fault point reliably.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to gas-insulated electrical equipment such as gas-insulated switchgear, and more specifically, when an accident such as a short circuit or ground fault occurs, This relates to a configuration for locating.

[Conventional technology]

The configuration of a conventional gas insulated switchgear is shown in FIG. In the figure, 30 is a circuit breaker, 31 is a linear disconnector, 32 is a line grounding device, and 33
1 is a cable connection device, CT is a cable splitting through type current transformer, 35 is a bus bar, 36 is a grounding device for inspection, 37 is a right-angled disconnector, and 3B is a charging part.

The charging unit 38 includes three phases that are collectively insulated and supported by an insulating spacer 39, housed in a grounded metal container 40, and S Fa gas of several atmospheres is sealed inside.

In the second SF, the gas acts as an insulating and arc-extinguishing medium.

The insulating spacer 39 not only supports the charging part 38 but also divides the space inside the grounded metal container 40 for each element to form a plurality of independent gas compartments A1 to A, and fills the SF. - Exhaust is only carried out where necessary.

In the gas-insulated switchgear mentioned above, if an abnormality such as a short circuit between phases or a ground fault of each phase occurs internally due to unforeseen factors such as usage conditions or due to durability life, etc., this can be detected and corrected. It is desirable to carry out repair work as quickly as possible.For this reason, in the past, each gas compartment A
Internal pressure detectors (not shown) are placed at each of ○ from 1 to ○ to take advantage of the fact that the internal pressure of the gas compartment where the accident occurred increases due to the arc energy released during short circuits and ground faults. It is designed to detect short circuits and ground faults, and to locate the fault point.

[Problem to be solved by the invention]

The plurality of gas compartments A1 to A1 generally have different volumes. For this reason, each increase value of the internal pressure of the gas compartments A1 to A1 to A with respect to a constant arc energy becomes smaller as the volume of the gas compartment becomes larger. Furthermore, since the ground fault current is small, it may not be possible to detect it if the gas compartment in which the ground fault has occurred has a relatively large volume. In particular, the ground fault current in an ineffective grounding system is very small, and therefore location during a ground fault is extremely difficult.

The object of the invention is to provide a gas-insulated electrical installation in which abnormality detection and fault location can be reliably carried out.

[Means to solve the problem]

The gas-insulated electric equipment of the present invention includes an instrument transformer that detects bus voltage, an instrument current transformer that measures the current flowing through each input/output line connected to the bus, and internal pressures in each of a plurality of gas compartments. calculating the total arc energy consumed within the plurality of gas compartments from the sum signal of the outputs from the potential transformer and the bus voltage signal from the potential transformer; From this total arc energy and the volume of each gas compartment,
means for calculating each estimated value of the internal pressure rise of each gas compartment, assuming that all of the calculated total arc energy is independently consumed in each of the gas compartments; and for each gas compartment. means for calculating the deviation of the actual measured value of internal pressure rise in each gas compartment obtained from the output of the internal pressure detector with respect to each of the estimated values, and locating the gas compartment where the deviation is the minimum as the accident point. It is something that

[Effect]

The total current flowing through the multiple input/output circuits connected to the busbar is normally zero, but due to a short circuit between phases or a ground fault in the busbar, if an arc occurs in one of the gas compartments, The current changes, and it is possible to calculate the arc energy based on this total current and the bus voltage.In this invention, a meter current transformer is provided for each of the plurality of input/output lines, and the bus voltage is detected by the transformer.

The sum signal of the outputs from said potential transformers corresponds to said total current, and therefore from this sum signal and the bus voltage signal obtained at said potential transformers, the total amount consumed in the plurality of gas compartments. Arc energy can be calculated.

Based on the total arc energy obtained in this way, assuming that this total arc energy is consumed independently in each of the plurality of gas compartments, then based on the volume of each gas compartment, Each estimated value of the internal pressure increase value in each gas compartment is calculated. Each of the plurality of gas compartments is also provided with an internal pressure detector that detects each internal pressure, and the actual value of the increase in internal pressure of each gas compartment obtained from the output from the internal pressure detector is The deviation from the estimated value is calculated. Then, the gas compartment where this deviation is the minimum is determined as the accident point.

In this way, in this invention, the estimated value of the internal pressure rise in each gas compartment is calculated by taking into account the volume of each gas compartment, and the gas compartment in which the internal pressure rise closest to this estimated value is observed is designated as the accident point. Therefore, even if an arc occurs in a gas compartment with a large volume or the arc energy is small such as during a ground fault, it is possible to reliably locate the gas compartment where the arc occurred as the accident point. can.

〔Example〕

FIG. 1 shows the electrical configuration of a gas insulated switchgear according to an embodiment of the present invention, and is used to locate the accident point when an accident such as a short circuit or ground fault occurs. The configuration is shown. In the description of this embodiment, reference will again be made to the above-mentioned FIG. 3. This gas insulated switchgear includes an instrument transformer PT that detects the voltage of the bus bar 35, and a voltage transformer PT that detects the voltage of the bus bar 35.
Instrument current transformers CT, -CTk (the instrument current transformer CT in Fig. 3 is one of these .

), internal pressure detectors S and -SR provided for each of the plurality of gas compartments A1 to A7 to detect the internal pressure of each gas compartment, and a central processing unit l that receives outputs from these and performs various calculations.
It is equipped with

The respective outputs of the internal pressure detectors S, -S, are connected to the gas compartment A,
-A, each reference voltage is determined corresponding to the internal pressure detector 81 to s7 output at the rated time, and each reference voltage and the internal pressure detector 31
~S,, the output is input to a subtracter 2 which subtracts the output, and the output of this subtracter 2 is passed from a multiplexer 3 to a sample hold circuit 4 and an analog/digital converter 5,
The signal is input to the data bus 6 to which the central processing unit 1 is connected. The output of the subtractor 2 is the gas compartment A I-A
.

corresponds to the amount of change in each internal pressure. At the stage before the multiplexer 3, there is an amplifier 7 for amplifying the output of the subtracter 2 to increase sensitivity when the difference between the output of the internal pressure detectors S, -S, and the reference voltage of the subtracter 2 is small. is provided.

It is also provided to the voltage transformers CT, -CT, output and voltage transformer PT ratio output calculation circuit 17. This calculation circuit 17 calculates the instantaneous internal loss energy W(t) in the plurality of gas compartments A1 to A, and the calculation results are transmitted from the multiplexer 3 to the sample hold circuit 4 and analog/digital converter 5. It is input to the data bus 6.

The data bus 6 includes a memory 8. whose storage area is used as a work area for the central processing unit l. an ink face circuit 10 that reads signals from the operation panel 9;
An ink face circuit 12 which receives a control signal derived to the data bus 6 and provides a display control signal to the display panel 11.
An interface circuit 14 connecting between the printing device 13 and the data bus 6 is connected. The data bus 6 is also connected to an ink face circuit 15 for controlling various relays, etc., and a signal from a differential relay for protecting the bus bar is transmitted to detect a short circuit or a ground fault on the bus bar 35. It is input via the ink face circuit 16.

FIG. 2 is a diagram for explaining the principle of locating the accident point (the gas compartment where a short circuit or ground fault has occurred) in this embodiment. The busbar 35 has a plurality of input/output lines 1. -4. are connected, and the aforementioned instrument current transformers CT, to CTk are provided in association with each of these input/output lines L-1, respectively. Further, a voltage transformer PT for measuring the voltage of the bus bar 35 is connected to the bus bar 35 .

Input/output line 11~! , the total power faI of each phase flowing to
a, Ib, l( are each phase current 1.11.,,!c, (j=1.2...
・, k), 1,=ΣI0... (1)
1,=ΣI hJ...
(2) 1, -Σt Cj ・
... It is expressed as (3). Note that normally, when no arc occurs due to a short circuit between phases or a ground fault, +a
J,=IC-0... (4) It is. Also, the instantaneous energy W(t) of internal loss is calculated as W(t)-?, assuming each phase voltage is t11 and 52. , I, +tblb+? c1. -(5)
Therefore, the arc energy E released at the time of an accident can be expressed as ΔP=C,x-... (8) (where t' is the failure duration time.)
.

On the other hand, if an accident such as a short circuit or ground fault occurs in the gas compartment, the temperature of the SF and gas will rise due to the arc energy at the time of the accident. This temperature rise causes S
F. The gas expands, thereby increasing the internal pressure of the gas compartment. For example, if the initial pressure of this gas compartment is P, and the internal pressure rises to P+ΔP due to the temperature rise at the time of the accident, then!・ t' ΔP−CI X ・
... (7) ■ However, CI... coefficient ■ ... Fault current ■ ... Volume of the gas compartment. This formula is expressed as follows: If the energy consumed in the gas compartment is E, ■ However, C2 is a coefficient.

It can be rewritten as This energy E can be considered as arc energy released due to an accident.

Therefore, the volume of each gas compartment A1 to A, , is Vr
, Vz , ..., vo, and assuming that an accident occurs in gas compartment A (where 1≦m≦n), the theoretical estimated value of the internal pressure increase value in gas compartment A, Δ
PM' is Δp,' = C, ·E/Vm - (9).

Furthermore, from this theoretical estimate ΔP,', the gas compartment A,
The deviation ε, (%) of the actual internal pressure increase value ΔP1 at is ΔP,′.By determining such a deviation for any m, the above deviation ε0. C2,..., C1 are obtained.

Next, these minimum values Min (εI IEl + ""r C1)...
・C1) is determined, and the gas compartment where the minimum deviation is obtained is designated as the accident point. In other words, an arc occurred in the gas compartment in which the internal pressure increase closest to the theoretically estimated value ΔP1' to ΔPo' of the internal pressure increase calculated by taking into account the volume of each gas compartment A I"" A- was observed. It will be judged as such.

The operation of this embodiment will be explained with reference to FIG. 1 again. When a short circuit between phases or a ground fault occurs in each phase, signals from each relay that operates in the event of a short circuit or ground fault to protect the bus bar 35 are transferred to the data bus 6 via the interface circuit 16.
, and is input to the central processing unit 1. As a result, the central processing unit 1 receives from the subtractor 2 or the amplifier 7 all the actual measured values ΔP of internal pressure increases in each gas compartment A1 to A.
, ~ΔP, 1 is obtained.

On the other hand, the arithmetic circuit 17 performs arithmetic operations based on equations (1) to (5) above to obtain the instantaneous internal loss energy W(t
) is calculated, the value of this instantaneous energy W(t) is also given to the central processing unit 1, and the central processing unit 1 calculates (calculation) from this instantaneous energy W(υ) based on the above equation (6). and calculates the total arc energy E consumed by 〇 to the plurality of gas compartments A1 to A1 at the time of the accident.Furthermore, the central processing unit 1 calculates this total arc energy E and each of the gas compartments A1 to A, . Based on the volumes V, -V, calculation according to the above equation (9) is performed, and in this way, each gas compartment when the total arc energy E is independently consumed in each gas compartment A1 to A1. Estimated values ΔP,' to ΔP9' of the increase in internal pressure of the chambers A1 to A, , are calculated.

Furthermore, based on the estimated values ΔP1' to ΔP7' and the actual measured values ΔP1 to ΔP7, the central processing unit executes the calculation according to equation 00), and in this way the estimated value ΔPl of the actual measured values ΔP1 to ΔP7 The respective deviations ε1 to ε7 from ' to ΔP1' are calculated.

Then, the minimum value of these deviations ε, to ε7 is determined, and it is determined that the accident occurred in the gas compartment where the minimum deviation was obtained. This information is displayed on the display panel 11, for example.

Each gas compartment A of the gas insulated switchgear shown in Figure 3
Table 1 shows the results of calculating the pressure increase value ΔP' when a correlated short circuit or ground fault occurs for Nos. 1 to A8. However, the gas compartments A'r and As accommodate the bus bar 35, and the gas compartments A'r and As accommodate the bus bar 35.

3, and is not shown in FIG. 3. The calculation results shown in Table 1 are ν in 66.
A gas-insulated switchgear is assumed, and the fault currents are: 2-phase short-circuit current: 6700 A 3-phase short-circuit current: 7730 A 1-wire ground fault current: 200 A.

(The following is a blank space.) Such a value of ΔP' is used in the calculation of the deviations ε and ε0 described above. Also, the estimated price ΔP shown in this Table 1
', it can be seen that the internal pressure increase value during a ground fault is one to two orders of magnitude smaller than the internal pressure increase value during a short circuit. In order to measure the internal pressure rise value at the time of this ground fault, in this embodiment, the aforementioned amplifier 7 for increasing the sensitivity is provided before the multiplexer 3. is selectively input to the sample and hold circuit 4.

By this switching, the detection span of the internal pressure increase value becomes approximately ±2 kgf/cm" in the case of a short circuit, and ±2 kgf/cm" in the case of a ground fault.
When the analog/digital converter 5 is a 12-bit one, it is approximately 0.001 kgf/cJ0.000.
05 kgf/cmz (D resolution is insufficient, it is possible to detect the increase in internal pressure at the time of a ground fault.

As described above, according to this embodiment, each gas compartment A I
-A-, each estimated value ΔP, '~ΔP1' of the internal pressure increase value is calculated taking into consideration each volume ■1~v7, and the actual measured value ΔP, ~ ΔP, deviation ε1 to ε. Since the gas compartment with the minimum is located as the accident point, the accident point can be accurately located regardless of the difference in volume of the gas compartments A1 to A. Furthermore, in this embodiment, in the event of a ground fault with a relatively small fault current as described above, the output of the subtracter 2 is further taken in from the multiplexer 3 via the amplifier 7, so the detection sensitivity is increased.
Therefore, ground faults can be detected reliably.

In the above embodiment, a gas insulated switchgear was taken as an example. However, the present invention is applicable to other gas insulated electrical equipment, and is applicable to detection of internal accidents such as short circuits and ground faults, and detection of accidents caused by such accidents. It can be widely used for those who wish to locate the accident point.

〔Effect of the invention〕

According to the gas-insulated electric equipment of the present invention, an estimated value of the internal pressure rise in each gas compartment is calculated by taking into account the volume of each gas compartment, and the gas whose internal pressure rise is closest to this estimated value is calculated. Since the compartment is regarded as the accident point, even if an arc occurs in a gas compartment with a large volume or the arc energy is small such as during a ground fault, the occurrence of the arc can be reliably detected and The gas compartment where the arc occurred can be reliably located as the accident point.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of a gas insulated switchgear according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the principle of locating a fault point in the gas insulated switchgear, FIG. 3 is a sectional view showing the configuration of a general gas insulated switchgear. DESCRIPTION OF SYMBOLS 1...Central processing unit, 2...Subtractor, 7...Amplifier, 17...Arithmetic circuit, A1-A,... Gas compartment, CT-CT,... Instrument variable Fluid, PT...Instrument transformer, S, -S,...Internal pressure detector

Claims (1)

[Scope of Claims] An instrument transformer that detects the bus voltage, an instrument current transformer that measures the current flowing through each input/output line connected to the bus, and an internal pressure that detects the internal pressure of each of a plurality of gas compartments. a detector; means for calculating the total arc energy consumed within the plurality of gas compartments from a sum signal of the outputs from the potential transformer and a bus voltage signal from the potential transformer; From this total arc energy and the volume of each gas compartment,
means for calculating each estimate of the internal pressure rise of each gas compartment, assuming that all of the calculated total arc energy is consumed independently in each gas compartment; means for calculating the deviation of the actual measured value of internal pressure rise in each gas compartment obtained from the output of the internal pressure detector with respect to each of the estimated values, and locating the gas compartment where the deviation is the minimum as the accident point. gas insulated electrical equipment.