JPH0519029A - Composite equivalent test circuit of circuit breaker - Google Patents

Abstract

PURPOSE:To enable maintenance inspection operation such as exchange of parts at a circuit breaker portion of an auxiliary switch to be reduced drastically by allowing a current source current to flow to only a series circuit of a circuit breaker under test and an auxiliary circuit breaker without flowing to the auxiliary switch. CONSTITUTION:A current source current 1c allows current to flow to only a circuit breaker 1 under test and an auxiliary circuit breaker 5 and a small short-circuiting current ia which is at least approximately 1/10-1/100 of the current source current ic is supplied to an auxiliary switch 6 from another power supply. Furthermore, a current superposition circuit consisting of a capacitor 9 which is precharged, a control gap 8, and a resistor is provided at a circuit side of the short-circuiting small current ia, thus enabling a phase difference of zero point of a current source current ic and the short-circuiting small current ia near a current-breaking zero point which is generated due to arc voltage, etc., generated according to circuit conditions and the circuit breaker and the short-circuiting small current ia to be controlled. No current source current ic is allowed to flow to the switch 6 and a small amount of current for maintaining an arc of the switch 6 is simply broken, thus preventing damage due to the arc at the circuit-breaking portion and eliminating a need for maintenance inspection such as exchange of parts at the circuit-breaking portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic equivalent test circuit for verifying a large-current breaking performance of a power circuit breaker, and more particularly to a four-parameter transient recovery voltage (Transient Recovery V
oltage; hereinafter abbreviated as TRV. ) Regarding the generation circuit.

[0002]

2. Description of the Related Art In recent years, the breakers for large-capacity electric power have been increased in voltage, and breakers having a rated voltage of 362 to 550 kV can now be constructed at one break point.

On the other hand, an international standard (international electrotec-hnical commission) concerning a breaking test of a power circuit breaker.
Standards of the Electrical Standards Study Group (Japanese Electrotechni
calCommittee; hereinafter abbreviated as JEC. ), The so-called four-parameter TR, in which the voltage peak value appears with a delay as the voltage waveform applied between the poles of the test breaker after the current is cut off.
V is specified. This defines four parameters of the initial peak time and the peak time of the TRV voltage waveform, and the initial peak value and the peak value corresponding to each time, and the withstand voltage of the four parameters TRV causes the test breaker to operate. It is determined to have a desired breaking performance. On the other hand, weil (W
eil) In the synthetic equivalent test circuit, the TRV generated by the circuit
Since the waveform is a vibration of a single frequency and is called a two-parameter TRV defined by a crest time and a crest value, many proposals have been made to improve this so that a four-parameter TRV can be generated. . However, due to the economical and technical problems of the test circuit equipment associated with the increase in the voltage per break point of the circuit breaker, it has not been widely spread in general. Therefore, it is desired to develop a synthetic equivalent test circuit that can generate a four-parameter TRV having a long crest time more economically and technically easily.

FIG. 3 shows an embodiment of a conventional four-parameter TRV generating circuit, and FIG. 4 is an explanatory view of the circuit phenomenon of FIG. This four-parameter TRV generation circuit is disclosed in the article issued in January 1988, iE, Transaction, On, Power, Delivery, Vol. 3, No. 1 (IEEE Transaction on Po
wer Delivery, Vol.3, No.1).

In FIG. 3, the right side of the illustrated circuit breaker 1 is a high voltage voltage source circuit, and the left side is a low voltage current source circuit. A current source current ic is supplied from a commercial frequency power source 2 through a reactor 3 for current adjustment, a short-circuit transformer 4, an auxiliary circuit breaker 5, an auxiliary switch 6, and a test circuit breaker 1. Here, the surge absorber 7 is often connected to the position shown for protection of the current source.

After passing the current source current ic, for example, the test breaker 1, the auxiliary breaker 5, and the auxiliary switch 6 are almost simultaneously.
Open. As shown in FIG. 4, the control gap 8 is discharged immediately before the final zero point of the current source current ic, and the precharged capacitor 9 to the control gap 8, the reactor 10,
The voltage source current iv is superimposed on the current source current ic via the auxiliary switch 6 and the test breaker 1. For example, according to the JEC standard, the superposition time point of the voltage source current iv by the current superposition method is before the zero time point of the current source current ic, and iv
The period t ₀ is only ⅛ of the cycle T of the voltage source current iv.
It is specified that it must be in the range of 1/4.

When the circuit breaker 1 finally succeeds in interrupting the voltage source current iv, the current i ₁ is caused by the residual voltage of the capacitor 9 as shown in FIGS.
12b, the current i ₂ flows through the resistor 13 and the capacitor 14, and the current i ₃ flows through the series circuit of the reactor 15 and the resistor 16. Eventually, a current of (i ₁ −i ₃ ) flows in the capacitor 12a and a current of (i ₂ + i ₃ ) flows in the capacitor 17. here,
The capacitance of the capacitor 14 is set to be considerably smaller than that of the capacitors 12 and 17. Therefore, when the voltage source current iv is cut off by the test breaker 1, TRV _1, which is the initial portion of the target TRV as shown in FIG. 4, is generated as a voltage drop between the current i ₂ and the capacitors 14 and 17. To do. By properly selecting the circuit conditions, the zero point t ₂₀ of the current i ₂ can be generated earlier than the zero point t ₁₀ of the current i ₁ . When the auxiliary switch 6 cuts off the current i ₂ at the zero point t ₂₀ , if there is no series circuit of the reactor 15 and the resistor 16, the terminal voltage of the test breaker 1 has an initial peak value as shown by the one-dot chain line in FIG. Keep a constant value close to U ₁ . Most of the voltage is shared between the terminals of the capacitor 14,
The voltage between terminals 7 is sufficiently low. After the current i ₂ is cut off, the capacitor 17 is continuously charged by the current i ₃ , so that the voltage is delayed and increased as indicated by TRV ₂ . As a result, a TRV waveform suitable for the four-parameter display represented by (TRV ₁ + TRV ₂ ) can be applied to the test breaker 1.

The most problematic point when the above-mentioned four-parameter TRV generating circuit is put into practical use is the auxiliary switch 6, and from the viewpoint of the economical efficiency and the evaluation of the breaking performance of the test breaker 1 described below. , Further improvement was desired.

[0009]

The above-mentioned prior art example is a system in which the current source current ic also passes through the auxiliary switch 6, and the breaking portion of the auxiliary switch 6 is damaged by the large current arc. For this reason, maintenance and inspection such as replacement of parts of the breaker were required for each test, and improvement was necessary in terms of economic efficiency in equipment operation. Further, since the auxiliary switch 6 needs to process a large current arc, a relatively large breaking performance is required. Since the auxiliary switch 6 also interrupts the current source current ic, it causes a decrease in the current source current ic and an increase in distortion near the current zero point. For this reason, there is a concern that the breaking performance of the test circuit breaker 1 that breaks in series may be assisted and the breaking performance may be excessively evaluated.

An object of the present invention is to greatly reduce maintenance and inspection work such as replacement of parts of the breaker of the auxiliary switch 6. Another object of the present invention is to minimize the number of auxiliary switches to which the current source current ic is energized, and to suppress the decrease of the current source current ic and the increase of distortion near the current zero point. It is to make it possible to verify the breaking performance of the device with higher accuracy. Another object of the present invention is to provide an efficient synthetic equivalent test circuit without failure of the breaking performance verification test such that the four-parameter TRV is not applied to the test breaker 1.

[0011]

To achieve the above object, the current source current ic is supplied only to the circuit breaker 1 and the auxiliary circuit breaker 5, and the auxiliary switch 6 is supplied with at least the current source current ic from another power source. The short circuit small current ia of about 1/10 to 1/100 is supplied. further,
For the purpose of controlling the phase difference between the current source current ic in the vicinity of the current interruption zero point generated by the circuit condition, the arc voltage generated in the circuit breaker, etc. and the zero point of the short circuit small current ia, a capacitor precharged on the short circuit small current ia circuit side. , A control gap, and a current superposition circuit consisting of a resistor.

[0012]

A large current source current ic is not passed to the auxiliary switch 6 and only a minute current for maintaining the arc of the auxiliary switch 6 is cut off. Maintenance and inspection such as replacement of the parts of the shutoff part are not required. Further, the auxiliary switch 6 only needs to process a small current arc, and a circuit breaker having a relatively low breaking performance can be used. The auxiliary switch 6 has a current source current i
Since c does not flow, it is possible to suppress the decrease of the current source current ic and the occurrence of distortion near the current zero point. Therefore, the test breaker 1
The breaking performance of can be verified more accurately. Further, by providing a current superimposing circuit to control the phase difference between the zero points of the current source current ic and the short-circuit small current ia, TR to the circuit breaker 1 under test is controlled.
The V application can be ensured.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows an embodiment of the synthetic equivalent test circuit of the present invention.
FIG. 2 is an explanatory diagram of the current zero phenomenon of the circuit of FIG.

The difference between the embodiment of the present invention shown in FIG. 1 and the conventional example shown in FIG. 3 is that the current source current ic is not supplied to the auxiliary switch 6 and the test breaker 1 and the auxiliary breaker 5 are connected. It is in the place where it was made to flow only to the series circuit. Further, a second current source circuit composed of a second short-circuit transformer 18 and a second reactor 19 connected to the power source 2 is newly provided, and a secondary-side current limiting reactor 20 of the second short-circuit transformer 18 is provided. , At least 1 of the current source current ic via the second auxiliary switch 21
A small short-circuit small current ia of about / 10 to 1/100 is supplied to the auxiliary switch 6. The short-circuit small current ia further flows from the auxiliary switch 6 to the second short-circuit transformer 18 through the test breaker 1 and the ground side of the short-circuit transformer 4. The second auxiliary switch 21 is, like the auxiliary circuit breaker 5, for disconnecting the second current source circuit from the voltage source circuit side after passing a current. Further, in the second current source circuit, a second control gap 22, a resistor 23, which is provided so as to form a closed circuit with a series circuit of the test breaker 1, the auxiliary switch 6, and the second auxiliary switch 21.
Also, a current superposition circuit including a second capacitor 24 having a charging device (not shown) is provided. Here, as with the surge absorber 7 on the short-circuit transformer 4 side, the surge absorber 25 is also provided on the short-circuit transformer 18 side.

During the test, first, the test breaker 1, the auxiliary breaker 5, the auxiliary switch 6, and the second auxiliary switch 21 are closed. The current source current ic from the first current source circuit is supplied to the test breaker 1 and the auxiliary circuit breaker 5, while the short circuit small current ia from the second current source circuit is supplied to the second auxiliary switch 21 and the auxiliary switch 6. And energize the test breaker 1. After that, for example, the test breaker 1 and the auxiliary breaker 5 are opened almost at the same time,
Subsequently, the auxiliary switch 6 and the second auxiliary switch 21 are opened. FIG. 2 shows the relationship of each current in the vicinity of the current zero point at that time. Current of each part ic, iv, ib, (ia + i
b) and (ic + iv + ia + ib) are measured by the flow dividers 26, 27, 28, 29 and 30 shown in FIG. 1, respectively. The control gap 8 immediately before the final zero point of the current source current ic
Is discharged, and the voltage source current iv is supplied from the precharged capacitor 9 through the control gap 8, the reactor 10, the auxiliary switch 6 and the test breaker 1. At this time, the zero point of the short circuit small current ia is the arc voltage generated by breaking the large current source current ic by the test breaker 1 and the auxiliary circuit breaker 5 through the primary side of the short circuit transformer 4. It is delayed by the time ta with respect to the zero point of the current source current ic, mainly due to the excitation of the device 18. For example, according to the JEC standard, the period t ₀ of only the voltage source current iv must be in the range of ⅛ to ¼ of the cycle T of the voltage source current iv. When this time ta becomes longer than the time t ₀ , the second auxiliary switch 21 is conducting due to the short-circuit small current ia at the zero point of the voltage source current iv. Therefore, the voltage source current iv is the second auxiliary switch 21. A further half-wave flows through the switch 21, the short-circuit transformer 18 and the ground side of the short-circuit transformer 4. In this case, since the TRV is not applied to the test breaker 1 at the zero point of the voltage source current iv, the breaking performance verification test fails. In order to prevent this, in the present embodiment, the second discharge gap 22 of the current superimposing circuit is connected to the voltage source current iv.
Is discharged at time tb immediately after superposition, and the discharge current ib from the second capacitor 24 charged in advance is superposed in the opposite direction to the short-circuit small current ia to forcibly advance the zero point of the short-circuit small current ia. It was done like this. Current (ia + i
The point b) is a zero point which is reached immediately after the superposition of ib and is cut off by the second auxiliary switch 21. After interruption of the current (ia + ib), ib continues to flow via the current limiting reactor 20 and the short-circuit transformer 18. After that, after the current ic is cut off by the auxiliary circuit breaker 5 and the test circuit breaker 1 cuts off the current iv, the TRV waveform suitable for four-parameter display is cut off as in the conventional example shown in FIG. Can be applied to the device 1. Here, the discharge timing tb of the second discharge gap 22 must be immediately before the time point when iv is cut off from the time point when the voltage source current iv is superimposed on the short circuit large current ic. However, in the synthetic equivalent test by the current superposition method, it is required that the current slope reaching the current zero point and the voltage increase rate of the TRV to be applied thereafter match the conditions in the actual system. In order not to affect the current gradient to the current zero point of iv that affects the cutoff performance, the discharge timing tb is within the range from the time when iv is superposed to the time when ic is cut off. It is desirable to do.

[0016]

According to the present embodiment, since the large current source current ic is not passed through the auxiliary switch 6 and the second auxiliary switch 21, the breaker is hardly damaged by the arc, and the test is performed for each test. Maintenance and inspection such as replacement of the parts of the shutoff part are not required. Therefore, there is an effect that it is possible to improve the economical efficiency of equipment operation. Further, the auxiliary switch 6 only needs to process a small current arc, and a circuit breaker having a relatively low breaking performance can be used. Since the current source current ic does not flow through the auxiliary switch 6, there is an effect that the reduction of the current source current ic and the occurrence of distortion near the current zero point can be suppressed to more accurately verify the breaking performance of the test breaker 1. is there. Furthermore, by providing a current superimposing circuit to control the phase difference between the zero point of the current source current ic and the short circuit small current ia, TRV application to the test breaker 1 can be ensured.

[Brief description of drawings]

FIG. 1 is a synthetic equivalent test circuit diagram of a circuit breaker according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a current zero point phenomenon of the embodiment of FIG.

FIG. 3 is a synthetic equivalent test circuit diagram of a conventional circuit breaker.

FIG. 4 is an explanatory diagram of a current phenomenon of the conventional example of FIG.

[Explanation of symbols]

1 ... Test breaker, 2 ... Power supply, 3, 19 ... Reactor, 4
… Short-circuit transformer, 5… Auxiliary circuit breaker, 6… Auxiliary switch, 8
… Control gap, 9… Capacitor, 18… Short-circuit transformer,
Reference numeral 20 ... Current limiting reactor, 21 ... Second auxiliary switch, 22 ... Second control gap, 23 ... Resistor, 24 ... Second capacitor.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yukio Kurosawa             4026 Kujimachi, Hitachi City, Ibaraki Japan             Tachi Works Hitachi Research Laboratory (72) Inventor Minoru Sato             1-1-1 Kokubuncho, Hitachi-shi, Ibaraki Stock             Hitachi, Ltd. Kokubu factory

Claims (2)

[Claims] Claim: What is claimed is: 1. A first current source circuit, a first capacitor, a first discharge gap, a first reactor, a first auxiliary switch, and a circuit breaker, and a voltage immediately before the zero point of the current source current. A voltage source circuit that superimposes a source current, and a second current source circuit that supplies a small current that returns via the second auxiliary switch, the first auxiliary switch, and the test breaker, The test circuit breaker, the first auxiliary switch, the second auxiliary switch, and a current superimposing circuit including a second discharge gap forming a closed circuit and a second capacitor in series. Equivalent test circuit for circuit breaker. 2. The discharge timing of the second discharge gap is set within a range from a time point when the voltage source current is superimposed on the current source current to a time point when the voltage source current is cut off. Circuit breaker synthetic equivalent test circuit.