JPS59100881A - Testing method of alternating current breaker - Google Patents

Abstract

PURPOSE:To use oscillation voltage appearing both terminals of a capacitor or reactor as power supply voltage for a test and to reduce significantly the cost of the test by discharging the charge of the capacitor previously charged through the reactor. CONSTITUTION:When a switch 2 is turned on, the charge of the capacitor 5 is discharged through the reactor 10 and oscillation voltage appears on both terminals of the reactor 10. If a breaker 3 to be tested is disconnected, the whole oscillation voltage is applied to both the terminals of the breaker 3, and if the breaker 3 to be tested is connected, the whole oscillation voltage is applied to both the terminals between a reactor 11 connected in series and a load 4 to be tested. To prevent resonance frequency from being actually changed by the impedance of the load 4 to be tested, 2pifL<Z (Z is the impedance of the load to be tested) is determined. In addition, L and C are defined so that the frequency (f) of the oscillation voltage becomes prescribed commercial frequency 50Hz or 60Hz. Consequently, the closing test at an optional voltage phase can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a test method for a switching test when switching a relatively small current equal to or lower than the load current in an AC circuit breaker.

A conventional example of a test circuit for this type of test is shown in FIG. In the figure, reference numeral 1 denotes an AC commercial frequency power source, and a short-circuit generator is usually used. 2 is a closing device, 3 is a test circuit breaker, 4
is the test load, and this load includes a power factor correction capacitor, a capacitor simulating a phase-advancing load such as an unloaded overhead power line or underground cable, a reactor, a resistor, and combinations thereof. For example, when measuring the voltage associated with closing and disconnecting in such a circuit, first turn on the closing device 2 to apply voltage to the power supply terminal of the circuit breaker under test 3, and then Turn on and off circuit breaker 3 -%. Further, in the breaking performance verification test of the test circuit breaker 3, the test circuit breaker 3 is turned on in advance, and the test circuit breaker 3 is turned on for the appropriate role, and then the test circuit breaker 3 is turned off.

In tests using such test circuits, 1. The short-circuit generator used as the power source is usually a large-capacity machine for short-circuit tests at large currents, and the power consumption associated with operation and testing is large, and the number of testers required is low. Considering the number and time involved, the cost of the exam is ignored.

2. There are 50Hz and 60Hz as the commercial frequencies of the circuit in which the same type of circuit breaker under test is used.Strictly speaking, the test should be conducted under both of these frequencies, but as a short-circuit test site, both of these frequencies are used. Since it is a heavy economic burden to install a power source with a certain frequency, normally only a power source with one of the following frequencies is installed.

Therefore, some kind of equivalent test must be performed for other frequencies, and it is not possible to verify performance or clarify the switching phenomenon by direct testing.

There were drawbacks such as. For example, a test circuit as shown in FIG. 2 is known to compensate for these drawbacks. In the figure, a capacitor 5 is charged by a commercial frequency AC power source 6 boosted from a low distribution voltage via a rectifier 7 comprising a rectifier 7a and a resistor 7b. When the closing device 2 is closed while the test circuit breaker 3 is closed, a discharge current flows through the test load, that is, the reactor 9. Next, the test circuit breaker 3 is shut off, thereby making it possible to verify the shutoff performance. The current frequency at this time is 50Hz or 60Hz depending on the capacitance of the capacitor 5 and the inductance of the handle 9.
It is assumed to be Hz. In this case, the capacity of the commercial frequency AC power supply is small, and therefore the power consumption associated with the test is extremely low.Also, it is possible to perform a simple test on a laboratory scale, which greatly reduces the test cost. . - In this test circuit, the load is limited to a reactor due to the necessity of generating an oscillating current, and furthermore, the power factor is limited to an axle with substantially zero power factor. Capacitor 5 for loads containing resistance with a power factor other than zero
The terminal voltage and test current attenuate rapidly, making it impossible to perform a correct test.

2. The recovery voltage applied to the terminals of the test circuit breaker 3 after current interruption becomes a DC voltage and does not match the actual voltage.

3. The closing test was also conducted under DC voltage, which did not match the actual test.

It has other drawbacks.

The present invention eliminates the above-mentioned drawbacks, has lower testing costs, and
It is an object of the present invention to provide a test method that is easy to carry out, and allows the test to match the commercial frequency of a circuit in which a circuit breaker of the same shape as the circuit breaker under test is used. The purpose of this is to form a resonant circuit by a capacitor that is charged from an AC power source via a rectifier and a capacitor that is connected to both terminals of the capacitor via a charger, and the resonant frequency of the resonant circuit is set to a predetermined value. The capacitance of the capacitor and the inductance of the reactor are set so that the impedance of the reactor at the commercial frequency is equal to the commercial frequency of 0.1 times or less than the impedance of the test load, and both terminals of the reactor are set. A load-side circuit including a test breaker and a test load is connected directly or through a transformer between This is achieved by using the oscillating voltage appearing between both terminals of the capacitor or the reactor as the power supply voltage for the test. The present invention will be explained in detail below with reference to embodiments shown in the drawings.

FIG. 3 is a test circuit diagram showing an embodiment of the present invention. Second
As can be seen from the comparison with the figure, the commercial frequency power supply 6, rectifier 7a, resistor 7b, capacitor 5, and input device 2 are connected to the second
It is exactly the same as the figure, and the load side of the dosing device 2 is according to the present invention. In other words, insert a2 into both terminals of capacitor 50.
A resonant circuit is formed by the reactor 10 and the capacitor 5 connected through the reactor 10, and a circuit breaker having the same shape as the circuit breaker under test is used between both terminals of the reactor 10.The reactor 11 simulates the impedance on the power supply side. The test circuit breaker 3 and the test load 4 are connected in series through the test circuit breaker 3 and the test load 4. When the charger 2 is now turned on, the charge on the capacitor 5 is discharged through the handle 10, and an oscillating voltage appears between both terminals of the reactor 10. Therefore, test circuit breaker 3! 19i
If it is in the closing position, the total oscillating voltage is applied between both terminals, and if it is in the closing position, the total oscillating voltage is applied across the reactor 11 and the test load 40, which are connected in series. The frequency of this oscillating voltage is expressed by the following equation (11).

Here, L is the inductance (H) of the reactor 10, and C
is the capacitance CF) of the capacitor 5.

In addition, the resonance frequency should not be substantially changed by the impedance of the test load 4, that is, the frequency of the oscillating voltage should not substantially change between when current is flowing through the test circuit breaker and when no current is flowing. Well, reactor (1
The inductance L of 0) is determined as shown in the following equation (2).

2gfL < Z , (Ji always2yrfL/Z≦0
．． 1), +21 where 2 is the impedance [Ω] of the test load 4. Satisfying formulas (1) and (2) above,
and f is a predetermined commercial frequency, i.e. 50 Hz or 6
The values of L and C are set to be 0H2. Also (2
) By determining the circuit constants according to the relationship shown in the equation, it is possible to arbitrarily select the type of load under test and the power factor.

Next, FIG. 4 shows an example in which the test circuit of the present invention is applied to a charging current interruption test. Here, FIG. 4 (al is a test circuit diagram, and FIG. 4 1b+ is an example of a voltage waveform. In this example, the test voltage of the test circuit breaker 3 and the oscillating voltage appearing at both terminals of the pressure beam handle 10 are transferred to the transformer. 12.In this way, even if the rated voltage of capacitor 5 itself is low, it is possible to test up to ultra-high voltage.Now, the photoelectric voltage of capacitor 5, voltage Eo, and transformer The waveform of Fig. 4 (bl) will be explained assuming that the transformation ratio of 12 is a, and the peak value of the terminal voltage of capacitor 13 serving as the load is EC. Vessel 1
The output voltage et of No. 2 becomes a damped oscillating voltage whose initial peak value is aEo. After the closing device 20 is turned on, the main contact of the test circuit breaker 3 is opened at time t1, and the current is cut off at time t2 at a current zero point (not shown). Then transformer 1
The output voltage et of 2 continues to oscillate at substantially the same frequency as before the current cutoff, and the EC
dc voltage remains. Therefore, a wire Er consisting of the output amount of the transformer 12, the pressure et, and the residual voltage EC of the capacitor 13 is applied between both terminals of the test circuit breaker 3, so that a circuit breaker with the same shape as the test circuit breaker 3 is used. The circuit conditions are exactly the same as those at the time of the charging current interruption test in the circuit shown in FIG. Further, after the current is interrupted by the test circuit breaker 3, while maintaining the residual voltage Ee of the capacitor 13,
After re-closing the closing switch 2, which has been opened once, the test circuit breaker 30 is closed at the phase of the output voltage e- of the transformer, thereby simulating a re-closing test of a no-load transmission line in an actual power system. be able to. The above is an example in which the test circuit of the present invention is applied to a charging current interruption test, but even when the test load is other than a capacitor, the test can be performed under substantially the same test conditions as the actual circuit.

As described above, the test method according to the present invention is a method in which the electric charge of a pre-charged capacitor is discharged through a reactor, and the oscillating voltage appearing at both terminals of the capacitor or the axle is used as the power supply voltage for the test.1. The amount of power required to charge the capacitor 5 is negligibly small compared to the amount of power required to operate the short-circuit generator.
In addition, the number of examiners and test time can be saved, so test costs can be reduced significantly.

2. Capacitance of capacitor 5 or reactor 1
50Hz arbitrarily by changing the inductance of 0
Tests can be performed at either commercial frequencies of 60 Hz or 60 Hz.

3. The type of test load is not limited, and the impedance of the reactor 10 is set sufficiently small, so the power factor is not limited.

4. Since an oscillating voltage is generated prior to the start of the test, it is possible to conduct a power-on test at any voltage phase.

Effects such as this can be obtained.

[Brief explanation of drawings]

Figure 1 shows an example of a conventional test circuit for load current switching tests, and Figure 2 shows an example of a test circuit designed for simple tests that reduce test costs, using only a pre-charged capacitor as the power source. 3 shows an example of a test circuit embodying the test method of the present invention, FIG. The voltage waveforms on the power supply side and load side of the test circuit breaker 3 are shown when a circuit breaker test is conducted using a capacitor. 2... Closing device, 3... Test breaker, 4... Test load, 5... Capacitor, 6... AC power supply, 7...
Rectifier, 10...reactor, 12...transformer. The best talent? Flash

Claims (1)

[Claims] A resonant circuit is formed by a capacitor charged from an AC power supply via a rectifier and a reactor connected to both terminals of the capacitor via a charger, and the resonant frequency of the resonant circuit is equal to a predetermined commercial frequency. The capacitance of the capacitor and the inductance of the reactor are set so that the impedance of the above-mentioned 7 vectors at the commercial frequency is 0.1 times or less the impedance of the test valve load, and the capacitance of the capacitor and the inductance of the reactor are set so that A load-side circuit including the test breaker and the test load is connected directly or via a transformer to the armpit when the electric charge previously charged in the capacitor is discharged through the front P reactor by inputting the input device. A test method for AC circuit breakers in which an oscillating voltage appearing between both terminals of a capacitor or the reactor is used as the test power supply voltage.