JPS59221680A - Testing method of reignition surge of gas insulation disconnecting switch - Google Patents

Abstract

PURPOSE:To obtain a large surge voltage by connecting in series a switch consists of an auxiliary gap part and a movable electrode which are driven till halfway and fixed, and connecting capacitors to both ends, and applying an opposite-polarity DC voltage or a voltage close to the rising of a commercial frequency voltage. CONSTITUTION:The switch part 14 consisting of a fixed electrode part 13 and the movable electrode part 12, and the auxiliary gap part 15 are connected in series and stored in a metallic container 11, and insulating gas is enclosed therein. A negative-side capacitor 18 and a DC voltage generator 20 are connected to one terminal, and a power-source side capacitor 22 and the secondary-side winding 23a of a transformer 23 are connected to the other through a reactor 21. The movable electrode part 12a is driven till halfway and then fixed, and a breaker 25 and a connector 26 are operated after the negative side capacitor 18 is charged so that the polarity of the rising voltage on the secondary side is opposite to that of the charging voltage of the capacitor 18. At this time, a large surge voltage is generated to test the switch.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a restriking surge testing method for a gas insulated disconnector against a ground fault phenomenon caused by a restriking surge when the charging current of the gas insulated disconnector is cut off.

[Technical background of the invention and its problems]

In a substation, disconnectors are opened and closed to disconnect equipment within the substation from the power system or to switch circuits. A disconnector opens and closes when an adjacent breaker is open, and the disconnector also switches on and off a minute charging current in a short line within the substation leading to the breaker.

Figure 1 shows an example of the configuration of a substation. For example, disconnector D
1 opens and closes the short line section m up to the circuit breaker CBI, and the disconnector D4 opens and closes the line section n when the circuit breaker D5 and the circuit breaker CB2 are open.

Also, disconnectors Da t Ds, DIlt D14,
When circuit breaker CB 6 is open, circuit breaker D9 is connected to bus B
Open and close 1. Here, TI and T2 are transformers, and Ll to L3 are power transmission lines.

For example, in a substation that uses a gas insulated disconnect switch filled with insulating gas such as SF, gas, the disconnect switch, breaker, bus bar, etc. shown in Figure 1 are all housed in a metal container filled with SF8 gas. They are broadly divided into insulated substations and composite gas-insulated substations, where only the busbar is an overhead line.

It is known that when the charging current is cut off by a disconnector, many restrikes occur, resulting in a load-side line-to-ground voltage waveform as shown in FIG. That is, the minute charging current is cut off almost simultaneously with the opening, and at that time, the power supply voltage v1 at the instant of the cutoff remains on the line on the load side. Since the power supply voltage is alternating current and changes, the difference between the residual voltage of this line and the power supply voltage is applied between the poles of the disconnector. At this time, the disconnector is still in the process of opening, and the inter-electrode insulation recovery is not sufficient, and it is re-ignited at the inter-electrode voltage e. When the line is re-ignited in this way, since the capacitance of the line is on the order of several hundred to several thousand picofarads, as soon as the flowing transient current attenuates, breaker is established, and the voltage on the load side line becomes equal to the power supply voltage v2 at that time. remains at a size consistent with that of Since the power supply voltage changes further, restriking occurs again at the electrode-to-electrode voltage e2. Similarly, the interelectrode voltages ea, e4, e51e61e
7 Repeat the re-ignition with ze8+... Since the distance between the poles of the disconnector gradually increases, in many cases e6) a7)
... > 82 > et When the interpole insulation of the disconnector recovers and the voltage becomes more than twice the peak value of the power supply voltage, the disconnection is completed without restarting.

A surge voltage is generated during these restrikes.

For example, the restriking surge at point a shown in FIG. 2 is illustrated by a straight line, but if this restriking phenomenon is temporally expanded and conceptually illustrated, it becomes as shown in FIG. 3. The surge voltage at this time has a high frequency because the line on the load side that is opened and closed is short, and in many cases, its fundamental vibration reaches several hundred kHz.

At the time of restriking, a high frequency current flows between the poles of the disconnector. If the disconnector cuts off this high-frequency current at the first current zero point as shown at point X in Figure 3(b), the voltage on the load side line will remain at the voltage at point y in Figure 3(a). become. However, this does not occur in real systems. Shutoff is established when the transient current at the time of restriking has sufficiently attenuated, and is shut off after the voltage on the load side line matches the power supply voltage. When the charging current is cut off by the new circuit switch, many restrikes occur, but the residual voltage on the line side is at its maximum, which is the peak value of the voltage on the power supply side. When considering the maximum restriking surge, the power supply line is at the peak value of the power supply voltage (hereinafter referred to as 1pu), and the load side line is at the peak value of the power supply voltage with the opposite polarity (hereinafter referred to as -1pu).
It is sufficient to consider the case of restriking with pu).

FIG. 4 shows an example of a conventional test circuit that cuts off the charging current of a disconnector that exhibits the above phenomenon in an actual system. The test disconnector (1) houses a breaker (1b) inside a grounded metal container (1a) and fills it with insulating gas (1c), and this breaker (1b) has terminals (2), (3). Terminal (2) is connected to ground via a load-side capacitor (5). High voltage side winding (8a) of transformer (8) via terminal (3) beam axle (6)
The power supply side capacitor (7) is connected in parallel to both ends of this high voltage side winding (8a), and the low voltage side winding (8b) of the transformer (8) is connected to the short circuit generator (9). Ru. The load side capacitor (5) simulates the capacitance of the load side line of the test disconnector (1). The test is conducted by opening and closing the disconnector (1) under test.

However, it has been known that when a gas insulated disconnect switch is re-ignited, a surge voltage generated at that time may cause a ground fault between the poles and a metal container at ground potential. The ground fault voltage is considerably lower than the capacitance when the disconnector is open or idle, and when a wire simulating a restriking arc is installed between the poles. The arc discharge between disconnectors has a large influence on the ground fault phenomenon.

In order to conduct a test equivalent to the actual system, focusing on the ground fault phenomenon caused by the restriking surge of the charging current of the gas insulated disconnect switch,
The surge voltage generated during restriking must be made equivalent to that of the actual system. However, this may be difficult in the opening/closing operation of the gas insulation disconnector under test in the conventional test circuit shown in FIG. The surge voltage at the time of restriking is mainly determined by the circuits of the power supply side capacitor (7), reactor (6), test gas insulation disconnector (1) (hereinafter referred to as test disconnector), and load side capacitor (5). do. Generally, the capacitance of the power supply side capacitor (7) is the same as that of the load side capacitor (5).
The larger the capacitance is, the larger the peak value of the surge voltage becomes. At both terminals of the disconnector, lpu,
In the case where the maximum surge voltage that causes re-ignition occurs at a voltage of -1 pu, the bushing (2) of the test disconnector (1)
), assuming that there is no capacitance in (3), a surge voltage of up to 3.0 times the theoretical maximum would occur at the terminals of the disconnector under test (1). However, in reality, bushings (2), (3)
The magnitude of the surge voltage will be smaller than this due to the capacitance of . In other words, the load side of the test disconnector (1) is 11p.
u, If the power supply side is re-ignited with lpu, both bushings (
The voltages of the capacitances in 2) and (3) are also 1 pu and 1 pu, respectively.
Since it is PU, both bushings (2) are immediately re-ignited.
The capacitance of (3) and the charging voltage of the load-side capacitor (5) become smaller than -1 pu. Surge voltage is mainly determined by the circuit that connects the capacitance of both bushings (2) and (3) in parallel with the load side capacitor (5), the axle (6), and the power supply side capacitor (7).
The magnitude of the surge voltage will be less than three times smaller. In addition to this, the power supply side capacitor (7) cannot be made large due to equipment reasons.
Due to unavoidable circuit losses, etc.

Generally, only about twice the surge voltage can be generated. Fourth
If the magnitude of the surge voltage generated in the test circuit shown in the figure is smaller than the magnitude of the surge voltage generated in the field, check whether the disconnector under test (1) can withstand the surge voltage in the field. The verification of
There was a problem to be solved that could not be achieved using the conventional test circuit shown in the figure.

[Purpose of the invention]

The present invention has been made with the above points in mind, and its purpose is to provide a restriking surge test method for gas-insulated disconnect f(3) that can increase the magnitude of surge voltage. be.

[Summary of the invention]

In order to achieve such an object, the present invention stores a switching section and an auxiliary gap section connected in series inside a gas insulated disconnector under test, and connects both ends of the series connection to each end of the gas insulated disconnect switch under test. Connect the first capacitor between the first terminal and ground, and connect the second capacitor between the second terminal and ground via the reactor. , by driving the movable electrode of the opening/closing part halfway and fixing it, and applying a voltage close to the rise of direct current or commercial frequency voltage of opposite polarity to the high potential side of each of the first and second capacitors. Its feature is to increase the magnitude of the surge voltage in the restriking surge test of the test gas insulating disconnector.

In addition, a DC voltage generator is connected to the high potential side of the first capacitor through a resistor, and the secondary winding of a power transformer is connected between the high potential side of the second capacitor and ground. Connect one terminal of the primary winding of the transformer to ground and −
A state in which a breaker, a closing device, and a commercial frequency AC power source are connected in series between the other terminal of the next winding and the ground, the first capacitor is charged by a DC voltage generator, and the breaker is closed. Preferably, a switch is turned on to generate a voltage in the secondary winding of the power transformer, and then the circuit breaker is opened.

Furthermore, it is preferable that the DC voltage generator is a device that generates a high voltage by connecting a number of charged capacitors in series by discharging a number of gaps.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A restriking surge test method for a gas insulated disconnector according to an embodiment of the present invention will be described below with reference to the drawings. In Figure 5,
The test gas insulated disconnector (10) is a metal container (1) at earth potential.
1) An opening/closing part (14) consisting of a movable electrode part (12) and a fixed electrode part (13) facing therein, and an auxiliary gap part (15) connected in series with this opening/closing part (14). Insulating gas such as SFe gas (1
0a) is enclosed. For example, one of the movable electrode parts (12) connected in series is connected to the bushing (16) which becomes the first terminal.
a), and the other auxiliary gap section (15) side is led out through the bushing (16b) which becomes the second terminal. The movable electrode section (12) is composed of a support section (12a) and a movable electrode (12b), and the movable electrode (2b) is opened and closed by an operating device (not shown). Further, the auxiliary gap part (15) stores the auxiliary gap (15a) inside the grounding container (1, 1c) supported by insulating parts (15b), (15b) such as insulating spacers, 11) is constructed by joining a grounding container (lla) housing the opening/closing part (14) and a grounding container (llb) on the bushing (1, 6b) side by a grounding container (], 1c).

A load-side capacitor (18) serving as the first capacitor is connected between the bushing (16a) of the test gas insulated disconnector (10) and the ground (17), and a high-resistance resistor is connected to the bushing (1, 6a). (19), although it is omitted in the illustration, for example, a DC voltage generator (2
0).

A power supply side capacitor (22) serving as a second capacitor is connected between the ground (17) and the bushing (16b) via the axle (21). This power supply side capacitor (22
) are connected to both terminals of the secondary winding (23) of the power transformer (23).
a), and a breaker (23b) is connected to the primary winding (23b).
5) and the commercial frequency voltage generator (27) via the input device (26).

Next, the effects of the present invention will be explained. The movable electrode (12b) of the opening/closing part (14) of the test gas insulated disconnector (10) is driven and fixed in the middle so that the discharge starting voltage between the poles of the opening/closing part (14) becomes 2 pu. Set to . Here, as described above, the peak value of the power supply voltage of the actual system is set to lpu, and the peak value of the power supply voltage of the opposite polarity is set to -1pu.

The circuit breaker (25) is closed and the switch (26) is opened. The output voltage of the commercial frequency voltage generator (27) is the same as that of the power transformer (2) when the closing device (26) is in the closing state.
3) The peak value of the secondary voltage (see voltage waveform A shown by the three-dot chain line in FIG. 6) is set to be slightly higher than lpu. First, load side capacitor (18)
is charged with the voltage of Ipu. Next, the input device (26) is turned on as shown at point b in FIG. 6 near the voltage zero point of the output voltage of the commercial frequency voltage generator (27). In addition, the one-dot chain line B in FIG.
The dashed dotted line C is the voltage of the load side capacitor (18) when there is the auxiliary gap (15a), and the voltage waveform shown by the solid line is the voltage of the power supply side capacitor (22).

A voltage close to the commercial frequency voltage rises on the secondary side of the power transformer (23). At this time, the closing device (26) is turned on so that the polarity of the voltage rising on the secondary side of the power transformer (23) is opposite to the polarity of the charging voltage of the load side capacitor (18). In this way, the gap between the poles and the auxiliary gap (
15), the difference between the charging voltage of the load-side capacitor (18) and the secondary voltage of the power transformer (23) is applied. As shown at point d in FIG.
When it becomes larger than the discharge voltage of the series circuit with 15a),
The gap between the poles and the auxiliary gap (15a) of the gas insulation disconnector (10) under test are discharged.

At this time, a surge voltage mainly determined by the circuit of the power supply side capacitor (22), the reactor (21), the auxiliary gap (15a), and the load side capacitor (18) is generated. Since the resistor (19) has a high resistance, it hardly affects the surge voltage. The current that flows through the breaker (25) when the input device (26) is turned on is mainly a leading current due to the power supply side capacitor (22), and the current wave carving shown by the solid line in FIG. ) is the primary current of This primary current (2) is cut off by a circuit breaker (25) at the current zero point as shown at point e in FIG.

At this time, the secondary voltage of the power transformer (23) is approximately at the peak value. After being cut off by the circuit breaker (25), the voltage of the power transformer (23) is transferred to the power supply side capacitor (22).
) and the power transformer (23) circuit to vibrate and attenuate.

The discharge starting voltage between the electrodes of the gas insulated disconnector (10) under test was set to 2 pu. Therefore, the discharge starting voltage of the series circuit between the poles of the test gas insulated disconnector (10) and the auxiliary gap (15a) is as follows:
a) is provided, so it becomes larger than 2pu. The surge voltage (1) in the case where there is an auxiliary gap (15a) shown by the two-dot chain line in FIG. 6 is larger than the surge voltage (2) in the case where there is no auxiliary gap (15a) shown by the one-dot chain line. This means that the power transformer (2
3) means that the voltage to ground on the secondary side is greater than lpu. Therefore, the magnitude of the surge voltage generated at the start of discharge is determined by
It becomes larger than when discharge starts at a voltage of u. As shown at point 0 in Figure 6, when the auxiliary gap (15a) is short-circuited, that is, when there is no auxiliary gap (15a), it shows a state in which the gap between the poles of the test gas insulated disconnector (10) is discharged at 2 pu. There is.

As described above, according to the present invention, the test gas insulation disconnector (10)
In a state where the electrode gap is 2 pu and discharge occurs, a larger surge voltage can be generated than in the conventional test method shown in FIG. 4. The magnitude of this surge voltage is determined by the auxiliary gap (
It can be adjusted by changing the distance between the gaps in 15a).

Next, other embodiments of the present invention will be described with reference to the drawings. The same parts as in FIG. 5 have the same symbols (=J'f).

In Figure 7, this test method is applied to a DC voltage generator (2
0) (see Figure 5) instead of a capacitor bank (30
) is used. This capacitor bank (30)
generates a DC high voltage by connecting a plurality of charged capacitors (30a) in series by discharging them through a plurality of gaps (30b) provided at both ends of the capacitors (30a).

Other configurations and arrangements are similar to those of the first embodiment of the present invention shown in FIG. 5, and similar effects can be obtained.

〔Effect of the invention〕

As explained above, according to the restriking surge test method for gas insulated disconnectors of the present invention, the test gas insulated disconnectors
It is possible to generate a larger surge voltage than the conventional test method in the discharge state.

[Brief explanation of drawings]

Figure 1 is a single line diagram showing the configuration of a normal substation, Figure 2 is a line diagram showing the voltage waveform when the charging current is cut off by a gas-insulated disconnect switch, and Figure 3 is a diagram showing the restriking surge in Figure 2. An enlarged diagram, FIG. 4 is a circuit diagram showing a conventional re-striking surge test method for a gas insulated disconnect switch, and FIG. 5 is a circuit diagram showing a rest-striking surge test method for a gas insulated disconnect switch of the present invention. 6 is a diagram showing the test method of FIG. 5, and FIG. 7 is a circuit diagram showing another embodiment of the present invention. (10)...Test gas insulation disconnector, (10a)...
Insulating gas, (11), (lla), (llb)
, (llc) - grounding container, (12) - movable electrode part, (12a) - support part, (12b) - movable electrode, (13) - fixed electrode part, (14)... opening/closing part,
(15)...Auxiliary gap portion, (15a)...Auxiliary gap, (15b)...Insulating member. (16a), (16b)-bushing, (]-7)
-=ground, (18)...Load side capacitor, (19)
...Resistance, (20) ...Commercial frequency voltage generator, (
21)...Reactor, (22)...Power supply side capacitor, (23)...Power transformer, (23a)...2
Secondary winding, (23b)...Primary winding, (25)...
- Breaker, (26)...Closer, (27)...Commercial frequency voltage generator, (30)...Capacitor bank,
(30a)...Capacitor, (30b)...Gap. Agent Patent Attorney Mr. Inoue Figure 1 Figure 8 (α) (Mu) Figure 4

Claims (3)

[Claims] (1) A switching part and an auxiliary gap part are connected in series and housed inside the gas insulating disconnector under test, and both ends of the series connection are connected to the first and second terminals of the gas insulating disconnector under test, respectively. A first capacitor is connected between the first terminal and the ground, and a second capacitor is connected between the second terminal and the ground via a reactor. The movable electrode is driven halfway and fixed, and the first and second
A restriking surge test method for a gas insulated disconnect switch, characterized by applying a voltage close to the rising edge of a direct current or commercial frequency voltage of opposite polarity to each high potential side of the capacitor. (2) Connect a DC voltage generator through the resistor on the high potential side of the first capacitor, connect the secondary winding of the power transformer between the high potential side of the second capacitor and ground, and One terminal of the primary winding of the power transformer is connected to ground, and a breaker, a energizer, and a commercial frequency voltage generator are connected in series between the other terminal of the primary winding and the ground. connected, the first capacitor is charged by the DC voltage generator, and with the breaker turned on, the closing device is turned on to generate a voltage in the secondary winding of the power transformer. The method for restriking surge testing of a gas insulated disconnector according to claim 1, wherein the circuit breaker is then opened. (3) Re-ignition surge test of a gas insulated disconnector according to claim 2, in which the DC voltage generator is configured by connecting a plurality of charged capacitors in series by discharging a plurality of gaps. Method.