JPS5818174A - Equivalent test method for circuit breaker - Google Patents

Abstract

PURPOSE:To perform an equivalent test approximating a small leading current interruption with a simple circuit constitution, by applying a commercial frequency voltage and a DC voltage to both terminals of a circuit breaker for test via a current suppressing high resistance. CONSTITUTION:An AC voltage is supplied to one side terminal of a circuit breaker 31 to be tested at the secondary winding of a transformer 7 via a current suppressing resistor 30. To another terminal, a capacitor 34 charged to a peak value of the test voltage in advance is connected in series via a current suppressing resistor 32 etc. Voltage measuring capacitors 36, 37, 38 and 39 are connected to both the terminals of the circuit breaker 31. When the circuit breaker 31 is opened, a voltage between the poles is instantly impressed. Taking the polarity of the charged capacitor 34 as negative, since the opening phase of the breaker is controlled at a point P in the earth voltage waveforms V1 and V2 of each voltage, a voltage of V3 is applied. The waveform between the poles is the same as the voltage waveform at small leading current test. Thus, an equivalent test approximating small leading current interruption can be made with a simple circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an equivalent test method for circuit breakers, and more particularly to an improved equivalent test method that approximates advanced small current interruption.

Various equivalent test methods have been proposed to verify the advanced small current breaking performance of circuit breakers.
With the increase in voltage capacity of circuit breakers, it has become extremely difficult to perform an actual load circuit breaker test, and an equivalent test is now required. However, conventional circuits have drawbacks such as high voltage concentration in a part of the circuit and complexity of the circuit, so there is a need for a good test circuit for verifying the withstand voltage characteristics of circuit breakers.

FIG. 1 shows the principle of the advanced small current test.

In FIG. 1, electricity is supplied from the generator 1 to the capacitor 3 through the test breaker 2, and after several cycles have elapsed, a cutoff operation is performed. In this case, as shown in FIG.
is leading the voltage V by π/2 radians, so the voltage to ground at the terminal of the current breaker and condenser 3 is a constant value V,
On the other hand, since the voltage Vo of the generator 1 changes with time as shown in FIG. 2 at the commercial frequency, a voltage shown by diagonal lines is applied between the poles of the breaker 2. This electrode voltage is 2 of the generator voltage Vo at the time of 0.5 cycles of the current breaker.
Twice as much will be applied. In the test circuit shown in Figure 1,
It is effective when the test voltage and current are relatively small, but
In the case of high voltage, there is a drawback that the installed capacity of the power supply 1 and capacitor 3 is insufficient. In addition, in this test, there is a drawback that a large number of tests must be performed in order to obtain the dielectric strength characteristics specific to the circuit breaker 2 through a small current interruption test.

FIG. 3 shows an improved test circuit.

In the figure, a power supply 5 is provided on the primary side of the transformer 7, and when a switch 6 is turned on, a current corresponding to the cutoff current is supplied to the secondary side of the transformer 7. A test breaker 9 is connected to the secondary side of the transformer 7 via an auxiliary breaker 8 to supply current. Further, the test circuit breaker 9 is connected in series to a capacitor 12 which has been charged in advance to a test voltage through a resistor 10 and an input voltage 5W11'i.

This voltage supply circuit includes a coupling capacitor 13,
When the voltage dividing capacitor 14 is connected, a voltage application waveform 15 to the breaker 9 is detected. In the above circuit configuration,
The circuit breakers 8 and 9 are operated to shut off, and the test voltage is supplied to the circuit breaker 9 by closing 5W11t before the circuit breaker. Circuit constants are determined so that the current flowing from the capacitor 12 through the high resistance 10 is sufficiently smaller than the current value from the transformer 7.

The voltage applied between the poles of the test circuit breaker 9 after disconnection is
The time constant determined by the series circuit of the capacitor 12, the coupling capacitor 13, the voltage dividing capacitor 14, and the resistor 1o, and the discharge characteristics determined by the charging and charging voltage of the capacitor 12 are shown, and the voltage is higher than the dielectric strength value inherent to the test circuit breaker 9. become 1+
, repeated dielectric breakdown. This dielectric breakdown increases as the distance between the poles of the circuit breaker 9 increases. The envelope curve 15 of the voltage between poles shown in FIG. It is determined that the circuit breaker 9 has predetermined voltage resistance characteristics.

In the conventional example circuit shown in Fig. 3, it is possible to perform an equivalence test on the breaker, but it is necessary to apply a voltage twice the peak value of the test voltage to the terminals of the breaker 9. The dielectric strength of one terminal of the device to ground is a problem. The same applies to test circuit equipment. Although this circuit can be applied when the test voltage is relatively low, it has the disadvantage that the test voltage is insufficient when the test voltage is high.

Furthermore, an improved version of this circuit is the circuit shown in FIG. In the figure, a first auxiliary breaker 20, a test circuit 21, and a second auxiliary breaker 22 are connected in series on the secondary side of a transformer 7, and are configured to supply an n1 short-circuit current. Further, a vibration suppressing means consisting of a resistor 27 and a capacitor 28 is connected to the secondary side of the transformer 7, and a terminal of the test breaker 21 is connected to the secondary side of the 1fC1 transformer 7 via a resistor 23. A capacitor 26, a discharge gap 25, and a resistor 24 are connected to the other terminal a of the breaker 21 under test.
It is configured to be supplied with a direct current voltage via the.

The test method for this circuit is that when the first auxiliary breaker 20, the test breaker 21, and the second auxiliary breaker 22 are closed, the generator 5 and switch 6 convert the preset voltage into a transformer. A current equal to the leading small current flows through the test breaker through the circuit 7. After the current is cut off, the recovery voltage that appears on the secondary side of the n1 transformer 7, which is set to match the test voltage of the small advancing current, is determined by the resistor 23 in the nw state where the vibration component is suppressed by the resistor 27 and capacitor 28. A voltage is applied to the terminal of the test circuit breaker 21 through the terminal. The waveform at this time is the 6th waveform.
It is indicated by Vb in the figure. At the same time, the test disconnector 21
A DC voltage is applied to the other terminal a of the capacitor 26, which has been charged in advance to a voltage substantially equal to the peak value of the recovery voltage, via the discharge gap 25 and the resistor 24. The voltage waveform at this time is indicated by v and n (DC voltage) in FIG.

As a result of the above, the sixth
The voltage (V-vb) shown in the figure is applied, and the maximum voltage can be obtained by making the peak value of the AC voltage different in polarity.
Furthermore, there is an advantage that it is not necessary to require excessive insulation performance from only one terminal of the test circuit breaker 21.

However, as an auxiliary breaker, it has better performance than the test circuit breaker, requires two additional circuit breakers, and the circuit configuration becomes complicated if the test circuit breaker and the test circuit breaker are included. Also, 1st. In order for the second auxiliary breaker to shut off reliably, it is desirable to open it earlier than the test breaker, and therefore the control becomes complicated. Furthermore, if the control of the discharge gap to which the DC voltage is applied is added, this control becomes extremely complicated, and also has drawbacks such as being difficult in terms of test resistance and impractical.

Furthermore, the maximum recovery voltage can be applied at 0.5 cycles after opening when the arc time is approximately zero. For this friend, it is necessary to control the opening phase. However, the short circuit current cannot be cut off unless the current phase is at the zero point, so AC
There is a drawback that the phase of the moment of contact opening cannot be changed with respect to the side voltage waveform, and therefore the maximum value of the recovery voltage applied between the electrodes cannot be temporally controlled.

The present invention focuses on the following points.

It is not limited by the test capacity based on the ground insulation characteristics, and is applied equivalently to the voltage between electrodes during a small lead current test. Since the current is suppressed, there is no need for an auxiliary breaker for separation from the current-carrying circuit. Therefore, the circuit configuration is very simple, and in the test sequence, even if AC and DC voltages are applied while the test breaker is closed, the DC voltage does not discharge in a short time, making it easy to control. becomes. Furthermore, since the current is suppressed to a negligible level, A
Since it is possible to cut off the C side voltage waveform at any phase, voltage can be applied at that moment and if the opening phase is changed,
Since the value of the recovery voltage at the instant of electrode opening can be changed, the applied voltage value can be changed with respect to the distance between electrodes. Therefore, there is an advantage that insulation recovery characteristics unique to the circuit breaker can be obtained.

As mentioned above, an object of the present invention is to provide a test circuit that can ensure insulation recovery characteristics.

The present invention suppresses the ground voltage and current at both terminals of the breaker under test by applying test voltages of commercial frequency voltage and DC voltage to both terminals of the breaker under test via a high resistance for current suppression. However, it is characterized by controlling the opening phase with respect to the commercial frequency voltage to obtain the insulation recovery characteristics unique to the circuit breaker, and applying the recovery voltage equivalently to the test voltage of lead/J% current. do.

A preferred embodiment of the present invention will be described. FIG. 7 shows an embodiment of the present invention. If the reference numerals are the same as those of the conventional circuit shown in FIG. 3.5, the explanation will be omitted.

In FIG. 7, when switch 6 is turned on, transformer 7
An alternating current voltage is supplied to one terminal of the test breaker 31 on the secondary side of the test circuit breaker 31 via a current suppressing resistor 30. An n* capacitor 34 previously charged with the peak value 1 of the test voltage is connected in series to the other terminal via the current suppressing resistor 32 and the input voltage 5W 33vi. Voltage measuring capacitors 36, 37, 38 and 39 are connected to both terminals of the test circuit breaker 31, and voltage waveforms 40, 38 and 39 are applied to the test circuit breaker 31,
"41 is detected.

In such a circuit configuration, the breaking current is a negligible current due to the current suppressing resistor 32, 30, so when the test breaker 31 is opened, the voltage between the electrodes is instantaneously applied. Now, if the polarity of the charging capacitor 34 is -, the ground voltage waveform V of each voltage as shown in FIG.
(=40).

V, (=41), the purpose is to control the opening phase of the breaker at point P, and there is a V shown by diagonal lines between the poles.

A voltage of ("Vt Vg) is applied. This inter-electrode waveform is similar to the voltage waveform during the small lead current test.

The opening phase can be controlled, for example, by using the voltage of a pilot generator (not shown) rotating in synchronization with the generator 5 as a reference, and by using a phase shifter (not shown) to synchronize with the phase of the generator voltage. A pulsed voltage is applied to the thyratron grid, at which point the thyratron becomes conductive, and an operating voltage is applied to the tripping coil of the breaker under test, allowing it to be energized and opened. If you set the generator voltage and the transformer's secondary voltage to be in phase, you can change the opening phase with respect to the transformer's secondary voltage waveform by controlling the phase of the pulse voltage. be able to.

When the test voltage is set higher than the specified voltage, the circuit breaker 3
7i! until it exceeds the inherent dielectric strength value of 1! Repeat electricity. As shown in FIG. 9, the envelope 42 of the discharge voltage appearing between the electrodes advances to a predetermined value, and the voltage waveform 43 between the electrodes when a small current is cut off.
If it is always larger than that, the test breaker 18 has predetermined voltage resistance characteristics.

As described above, by controlling the P point of the opening phase of the test breaker to the left and right, it is possible to approximate the voltage waveform during advanced small current interruption, and also change the applied voltage point with respect to the distance between poles. As a result, it is possible to understand the breakdown voltage characteristics.

First, this circuit has a very simple circuit, and the test sequence is also simple. It is similar to a small current test because it conducts ground insulation, and it has the characteristic that it is not limited by the test voltage.

-Also, since voltage is applied via the current suppression resistor,
The breaking section including the electrode section will not be damaged.

In FIG. 7, either one of the resistors 30 and 32 has the same characteristics.

According to the present invention, an AC voltage from a commercial frequency power source and a DC voltage from a pre-charged capacitor are applied to both ends of a test breaker via a current suppression resistor, and
By controlling the opening phase of the breaker with respect to the AC side voltage phase, the voltage applied between the breaker poles can be made to have a different polarity at its maximum value. Furthermore, since the current is negligible, the breaking section including the electrodes is not damaged, and the number of tests can be increased. Since there is no need to provide large ground insulation to a part or specific part of the test circuit, it can be constructed using normal equipment. In addition, the test circuit is extremely simple, and test method □ does not require any special technology.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the principle of a leading small current test circuit using a conventional actual load test, Fig. 2 is a voltage and current waveform diagram in Fig. 1, Fig. 3 is a conventional equivalent test circuit diagram, and Fig. 4 is Figure 3 is a characteristic diagram explaining the action, Figure 5 is an improved version of Figure 3.
6 is a waveform diagram of FIG. 5, FIG. 7 is an equivalent test circuit diagram according to an embodiment of the present invention, and FIGS. 8 and 9 are voltage characteristic diagrams of FIG. 7. Ruru. 7...Transformer, 11...Switch, 30.32...
・Current suppression resistor, 31... Test breaker, 34...
・Conte 1st Myo 3rd vJG Zu Atsushi 7th 80th ■ Atsushi 90'-Yu

Claims (1)

[Claims] 1. A first voltage supply device with a switch Kanakura that supplies some terminals of the commercial frequency power supply circuit and the recovery voltage of the commercial frequency power supply circuit breaker, and one terminal of which is grounded and the capacitor is charged in advance. f′L7 is connected to a second voltage supply device including a switch that supplies a DC voltage approximately equal to the peak value of the recovery voltage to the other terminal of the test breaker via a current suppression resistor. An equivalent test method for a circuit breaker, characterized in that by applying voltage to both terminals of the circuit breaker, the influence of arc current is eliminated and the waveform between the electrodes is made equal to that at the time of small current interruption.