JPH03296677A - Composite tester for leading small current breaking test of breaker - Google Patents

Abstract

PURPOSE:To conduct a test matched with an applied frequency of a breaker by a method wherein a parallel resonant circuit of a capacitor and a reactor is connected in parallel to a voltage source circuit, the capacitor is charged after a current is interrupted, and a voltage of the frequency is impressed on the breaker to be tested. CONSTITUTION:A voltage source circuit 7 sets values of an impedance 10 for excitation and current adjustment of a short-circuit generator 1, a voltage source transformer 4a, a tape of a current source transformer 4b and a voltage source capacitor 5b so that a prescribed breaking current Ip and a prescribed circuit voltage be supplied from a current source circuit 8 to a breaker 6 to be tested. Simultaneously with interruption of the current Ip, the generator 1 is cut off from the circuit 7 by an auxiliary breaker 2a and the circuit 8 is cut off from the breaker 6 by a breaker 2b. At time, a capacitor 5a and a capacitor 5b for parallel resonance are charged with a voltage. When the current Ip is interrupted, a source-side voltage Vs is oscillates at a resonance frequency determined by a reactor 3, the transformer 4a, etc. An interpolar voltage Vp being a difference voltage between the voltage Vs and a voltage Vl charged on the capacitor 5a is impressed on the breaker 6.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is particularly directed to the progress of a circuit breaker that enables verification of small current interrupting performance in a method in accordance with the usage conditions in a circuit breaker system. This invention relates to a synthetic test device for current interruption tests.

(Prior Art) Generally, when a circuit breaker opens or closes an unloaded power transmission line or a power cable, it interrupts a charging current of ground capacitance, that is, a small advancing current. When verifying the performance of such a circuit breaker at a test site, a small current test is performed using a capacitor bank as a load instead of a power transmission line or power cable. The test circuit is shown in FIG. 3, and the electrical phenomenon at the time of interruption is shown in FIG. 4 and will be explained.

In FIG. 3, a short-circuit generator 1 serving as a test power source is connected to one end of the test circuit breaker 6, and a load capacitor 5 is connected to the other end. When the test circuit breaker 6 is opened at time t□ in FIG. is charged. The interpole voltage Vp of the test circuit breaker 6 is (Vs - Vj2), and the power supply side voltage Vs
It changes by Em(1-cO5ωt) with the change of . However, ω is the angular frequency of the power source.

This value increases to twice the peak value of the power supply voltage after 1/2 cycle of the power supply frequency. In this way, the small current interruption test is carried out.6 By the way, the small current interruption test verifies that the test circuit breaker can withstand a voltage twice the peak value of the power supply voltage mentioned above, which is applied between the poles of the circuit breaker under test after the current is interrupted. If the dielectric strength between the poles of the circuit breaker under test is insufficient, dielectric breakdown will occur and current will flow again, resulting in so-called restriking. If this restriking occurs in the power system, abnormal voltage will occur and threaten the insulation of other equipment.

A problem with such progressive small current interruption tests is when the frequency of the system to which the circuit breaker is applied differs from the test current frequency at the testing site. For example, when testing a circuit breaker used in a 60Hz system with a 50Hz power supply, the maximum voltage is applied between the poles of the circuit breaker in 1/2 cycle after the current is interrupted, but the time for which this voltage is applied is: In the 60 Hz system, the time after current interruption is 8.3-s, while in the 50 Hz system, it is 101 Is, which makes the test easier than the actual use of the circuit breaker.

For this reason, in a test site with only a 50Hz test power supply, 60H
In order to cover the z-system voltage waveform with a 50Hz test power supply, tests are often simply carried out by simply increasing the voltage. The test is performed by multiplying the test voltage by 1.2 in order to adjust the rising part of the recovery voltage to 5Of (60Hz with the z power supply).

However, although the same voltage waveform can be obtained at the rising part of the recovery voltage, after 6.8ms after the current is interrupted, a voltage higher than the 60Hz recovery voltage is applied to the test circuit breaker, and the peak value is 1.2 times higher. However, unlike the conditions in which the circuit breaker is used in the system, the test is severe. Proceeding to Fig. 5, a comparison of the voltage waveforms between the circuit breaker electrodes when a small current is interrupted is shown. vl is a 50Hz voltage waveform, v2 is a 60Hz voltage waveform, v3 is 50H
This is a voltage waveform when the voltage of z is increased by 1.2 times.

(Problems to be Solved by the Invention) As explained above, in the advance small current breaking test of a circuit breaker, when the frequency of the system to which the circuit breaker is applied and the test frequency of the test site are different, the circuit breaker is There was a problem in that it was not possible to perform tests according to the frequency of the voltage applied to the

An object of the present invention is to make it possible to arbitrarily vary the frequency of the voltage applied between the circuit breaker poles after current interruption in a small current interruption test circuit where the test power supply frequency is advanced, and to match the applied system frequency of the circuit breaker. It is an object of the present invention to provide a synthetic test device for advanced small current interruption testing of circuit breakers that enables testing.

[Structure of the invention]

(Means for Solving the Problems) In the synthetic test device for advanced small current interrupting tests of circuit breakers of the present invention, a current source circuit that supplies a specified current to the circuit breaker under test and a current source circuit that supplies a specified current to the circuit breaker under test and A parallel resonant circuit of a capacitor and a reactor is connected in parallel to the voltage source circuit, and after the current is cut off, the test power source is disconnected by an auxiliary circuit breaker, and the capacitor of the parallel resonant circuit is It is characterized in that a voltage is applied to the device under test at a frequency determined by a resonant circuit (capacitor and reactor).

(Function) According to the synthetic test device of the present invention, at the same time that the test circuit breaker interrupts the current at the current zero point, the test power supply is disconnected by the auxiliary circuit breaker, and the capacitor of the parallel resonant circuit and the capacitor of the voltage source circuit are The voltage at the peak value of the voltage source voltage is charged. The difference voltage between the voltage that oscillates at a frequency determined by the capacitor and reactor of the parallel resonant circuit and the voltage charged in the capacitor of the voltage source circuit is applied to the test circuit breaker.

Here, by adjusting the parallel resonant circuit, the frequency of the applied voltage can be changed arbitrarily, making it possible to carry out a small advance current breaking test at the frequency at which the circuit breaker is actually used.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. Short-circuit generator 1 serving as the test power source in Figure 1
is connected to the primary winding V□ of the voltage source transformer 4a via the auxiliary circuit breaker 2a, and the resonance reactor 3 is connected in parallel to the primary winding l111, and the resonance reactor 3 is connected to the secondary winding v2. Connect capacitor 5a.

Further, a series circuit of a voltage source capacitor 5b and a test breaker 6 is connected to the secondary winding v2, and one pole of the test circuit breaker 6 is grounded to form a voltage source circuit 7.

In addition, the short-circuit generator 1 has a current setting impedance 10.
through the primary winding W of the current source transformer 4b. connect to,
The secondary winding wire 2° is connected to both poles of the test circuit breaker 6 via the auxiliary circuit breaker 2b to form a current source circuit 8. The current setting impedance 10 uses a capacitor or a reactor, and in the case of a reactor, a current source transformer 4b
The polarity may be reversed to connect a-b' and b-a', but if this is not possible, it may be left as is. The voltage source transformer 4a, the resonant reactor 3, and the resonant capacitor 5
a becomes a power source that is applied to the test circuit breaker 6 as a resonance power source circuit 9 after the test power source is disconnected by the auxiliary breaking amounts 2a and 2b.

Next, the present invention will be explained in detail. The voltage source circuit 7 excites the short-circuit generator 1, has a current adjustment impedance 10, a voltage source transformer 4a, and a voltage source transformer 4a, so that the current source circuit 8 supplies a specified breaking current IP and a specified recovery voltage to the test circuit breaker 6. The tap of the current source transformer 4b and the value of the voltage source capacitor 5b are set. At this time, the tap of the current source transformer 4b is not particularly related to the test voltage, but a supply voltage that is not affected by the arc voltage of the auxiliary circuit breaker 2b and the test circuit breaker 6 is required.

The test circuit breaker 6 and the auxiliary circuit breakers 2a and 2b are set to break at the current zero point of the breaking current Ip, time t2, and are opened at time t1. At the same time as the interrupting current Ip is interrupted, the short circuit generator 1 is disconnected from the voltage source circuit 7 by the auxiliary circuit breaker 2a, and the current source circuit 8 is disconnected from the test circuit breaker 6 by the auxiliary circuit breaker @2b.

At this time, the parallel resonance capacitor 5a and the voltage source capacitor 5b are charged with a voltage of the peak value Em of the power supply side voltage Vs. When the cutoff current Ip is cut off, the power supply side voltage Vs
begins to vibrate at a resonant frequency determined from the frequency of the test power supply by the parallel shared reactor 3, voltage source transformer 4a, and parallel resonant capacitor 5a of the parallel resonant power supply circuit 9. Then, the test circuit breaker 6 is applied with a voltage between electrodes Vp, which is a difference voltage between the power supply side voltage Vs shown in FIG. 2 and the voltage v2 charged in the voltage source capacitor 5a.

When the voltage Vs on the power supply side reaches the peak value 1/2 cycle after the current is cut off, the interpole voltage vp of the test circuit breaker 6 becomes twice the peak value Em of the power supply voltage, and becomes approximately Emm(L-cos
ωt) and is applied to the test circuit breaker 6. (However, ω is the resonant angular frequency of the parallel resonant power supply circuit 9) This is equivalent to the voltage applied to the circuit breaker when cutting off a small advance current, and the reactor 3 and capacitor 5a of the parallel resonant power supply circuit 9
By adjusting the frequency, the circuit breaker can be made to match the frequency of the system in which it is used. As a result, even if the test power supply has a constant frequency, the frequency of the applied voltage can be changed to perform a small advance current interruption test of the circuit breaker.

Note that even if the configuration of the parallel resonant power supply circuit 9 of the circuit breaker advance small current test device in FIG. Primary side v1 and secondary side v1.

Parallel resonance capacitors 5a may be inserted separately.

In this way, the parallel resonance reactor 3 and the parallel resonance capacitor 5a can be set on the primary side and the secondary side of the voltage source transformer 4a so as to obtain a predetermined resonance frequency.

〔Effect of the invention〕

As explained above, according to the present invention, even if the test power supply has a constant frequency, the frequency of the applied voltage can be varied by supplying the applied voltage from the parallel resonant power supply circuit after the test circuit breaker interrupts the current. It is possible to provide a synthetic test device for a small advance current interruption test of a circuit breaker, which enables an advanced small current interruption test in accordance with the frequency of the system to which the circuit breaker is applied.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a synthetic test device for advanced small current interruption tests of circuit breakers according to the present invention. FIG. 2 is a diagram of voltage and current waveforms at the time of interruption in the circuit shown in FIG. 1. Figure 3 is a circuit diagram of the basic circuit breaker advanced small current interruption test. FIG. 4 is a diagram of voltage and current waveforms at the time of interruption in the circuit shown in FIG. 3. FIG. 5 is a waveform diagram of the voltage applied between the poles of the advanced small current interrupter. 1... Short circuit generator 2a, 2b... Auxiliary circuit breaker 3... Reactor 4a, 4b...
・Transformers 5a, 5b...Capacitor 6...
Test circuit breaker 7...Voltage source circuit 8...Current source circuit 9...Parallel resonant power supply circuit 10...Impedance for current setting (8733)

Claims (1)

[Claims] A first auxiliary circuit breaker and a primary winding of a first transformer are connected in series between the terminals of the test power supply, and a first reactor is connected in parallel to the primary winding, and a first reactor is connected in parallel to the primary winding. A voltage source circuit is formed by connecting a first capacitor and a series circuit of a second capacitor and a test circuit breaker in parallel between the terminals of the secondary winding of the transformer, and a voltage source circuit is formed between the terminals of the test power supply. is connected to the primary winding of a second transformer through a current setting impedance, and its secondary winding is connected to both ends of the test circuit breaker through a second auxiliary circuit breaker. Synthetic test device for advanced small current interruption test of a circuit breaker, characterized by forming a current source circuit