JPS62229078A - Polarity tester of transformer - Google Patents

Abstract

PURPOSE:To enable simple and dependable polarity measurement, by giving a square wave to the primary side of a specimen transformer, and detecting only a signal of a single-pole characteristic generated in synchronization with one of the levels of the square waves among voltage signals induced on the secondary side. CONSTITUTION:An oscillator OSC generates a square-wave voltage signal VOSC of a constant frequency. By operation of a switch by this, the primary current I1 of a square-wave shape is allowed to flow into a transformer T from a voltage source E. By this action, a peak-pulse-shaped voltage signal V2 of each different polarity is induced on the secondary side of the transformer T of rise-up and breaking time. Consequently, when a signal of, for example, positive polarity is detected in synchronization with one level of the primary side square- wave, for instance, a higher level, in the case of the depolarization, above pulse signal is detected at every rise-up time of the square-wave, however, in the case of the additive polarity, it is not detected at all.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transformer polarity tester that enables a transformer polarity test to be performed easily and reliably.

[Conventional technology]

In principle, instrument transformers and transformers are depolarized, so it is necessary to check the polarity before molding or storing them in a container. Also, when installing a directional protective relay, the polarity must be confirmed and J3 must be checked.

In polarity tests using transformer test equipment, if the polarity is additive, 2
Since double the voltage or current is generated, a standard transformer and transformer testing equipment are required to detect and cover this, and it is troublesome to connect them. Therefore, testing is usually performed using the 1-1 nick method, which is a simpler method.

The kick method will be explained using FIG. 3 using a current transformer as an example.

J in the figure: A DC power source (for example, a dry battery) is connected to the primary side of the current transformer under test T via a switch S, and a DC ammeter (double swing meter) A is connected to the secondary side.

In this connection, when the switch S is closed, the negative current 11 flows in the direction of the arrow. At this time, if the secondary current I2 flows in the direction of the arrow, it is depolarizing, and if it flows in the opposite direction, it is additive, and this is determined based on the direction of one tail of the DC current h1. Also, when the switch is turned from open to open, the secondary current flows in the opposite direction, so the swing of the current 1 is reversed.

When the number of primary turns is greater than the number of secondary turns, such as in a transformer, applying current from the secondary side detects a larger voltage, which is why this is done.

[Problem that the invention seeks to solve]

In a transformer with a large number of turns, the secondary induced voltage is also large, so the current M1 swings to the extent that the -order current must be limited by a resistor.However, in a current transformer with a small capacity, the number of turns is large. Because the secondary induced voltage is small (for example, in a 12OA15Δ current transformer, the number of turns is 1 for the primary and 24 for the secondary), the ammeter swings out to the extent that a nail twitches, and testing requires skill. It is.

For the purpose of improving sensitivity, it is conceivable to provide an amplifier at the secondary terminal. However, when amplifying, it is sufficient to faithfully amplify both polarities, but if the secondary induced voltage is large,
Sometimes it is small, and when it is large, it must be saturated. Also, when amplifying with such an amplifier, when the switch is closed! ! Due to the tsuttering, signals of both polarities are generated, and the polarity cannot be determined.

An electronic switch can be used as the switch, but in order to perform a manual test, avoid contacting the lead wires with the K and K terminals instead of the switch, and then check which direction the ammeter is placed at. Therefore, it is impractical to avoid the distortion because it requires extra steps in the test.

The present invention solves this drawback, provides reliable test results, is easy to operate, and can be applied to all types of current transformers, from small-capacity current transformers, current transformers with a human capacity of H>, to ultra-high voltage transformers. Zarura offers a polarity tester that can be used for transformers.

[Failure to solve the problem]

Therefore, the present invention supplies a square wave to the primary side of the transformer under test, thereby transmitting only the voltage signal of either positive polarity or negative polarity induced on the secondary side of the transformer to the primary side. It detects in synchronization with one of the different levels of a given square wave, and uses the detection signal to activate an indicator, such as a display lamp.

[For production]

When a square wave is supplied to the primary side of the transformer under test, pulse-shaped voltage signals with different polarities are induced on the secondary side at the rising edge of the square wave and the falling edge ``, ``i''. The polarity of the signal also depends on the polarity of the transformer.In other words, if it is depolarized, a positive signal will be generated at the rising edge, and if it is additive, a positive signal will be generated at the falling edge. , 4i'r Vj of one polarity,
For example, if only a positive polarity signal is detected in synchronization with one level of the negative side square wave, for example, a high level, then in the case of depolarization, the above pulse signal will be detected at the rising edge of the square wave. However, in the case of additive polarity, it is not detected at all (2. By activating a display device, such as an indicator, a lamp, or a current/pressure meter based on the detection result, an indication can be obtained only in the case of either depolarization or addition, making it possible to confirm the polarity.

(Example) The embodiments shown in the drawings will be explained below.

FIG. 1 is a circuit diagram showing an embodiment in which the present invention is applied to a current transformer test together with a current transformer. This embodiment is composed of a square wave generator SQ, a synchronization detection circuit consisting of a class B amplifier OP, circuits 1 to 0, and an alarm B. The square wave generator SQ generates a square wave signal with a constant frequency by opening a switch S (for example, a 1H range resistor) connected in series with a DC power source E (for example, a dry battery) with a constant frequency signal from the excavator O8C.b There is -C. The output terminal of this square wave generator SQ is connected to the primary terminal L of the current transformer under test T. In the actual test, this connection is made by touching the terminal L with a hand using a clip or a prong. In a similar manner, the input terminal of the amplifier OP is connected to the secondary terminal of the current transformer T, ρ. Each output signal of the amplifier oP and the oscillator osc is input to the circuit G.

Circuit G is an AND circuit that outputs a signal only when both J signals are above a predetermined threshold level, and the output signal is used as an output signal from the synchronization detection circuit to generate an alarm. It is input to B. The oscillator B vibrates the speaker at the cycle of the signal input from the synchronization detection circuit to generate the tg sound.

Next, the operation of the above configuration will be explained with reference to the waveform diagram of FIG.

The oscillator oSC generates a constant frequency square wave voltage signal V as shown. 8o is generated. By opening and closing the switch S, a rectangular primary current 11 flows from the voltage source E to the current transformer 29T. As a result of this operation, peak pulse-like voltage signals V2 having different polarities are induced on the secondary side of the current transformer T when the negative current 11 rises and falls, respectively. When the current transformer T has depolarization, the secondary voltage signal (2) induced by the rise of the negative current (1) has positive polarity, and the secondary voltage signal (2) induced by the fall has negative polarity.

Further, the polarity of the secondary voltage signal V2 in the case of additive polarity is opposite to that in the case of depolarization as shown in J in FIG. 2(b).

This secondary voltage signal V2 is amplified only in its positive polarity pulse portion by the amplifier OP and shaped into a rectangular waveform pulse signal V', which is input to one terminal of the circuit G. This gate circuit G receives a square wave voltage signal v o from an oscillator O8C which is input to one terminal of the gate circuit G.
A voltage signal V is generated by detecting only the pulse signal v' from the amplifier ○P, which is input synchronously when sc is at a high level.

Output ut.

Therefore, if the current transformer bottom is depolarized, the square wave voltage signal FV. 8o rose ``, +1 pulse signal V'
is emitted, so the gate circuit G continuously outputs a pulse-like voltage signal "vout" at the above rising time angle, and J,
-), lamp sounder B sounds. On the other hand, if the current transformer T is of additive polarity, the square wave voltage signal V. Since the pulse signal V' is emitted when 8c falls, no signal is emitted from circuits G1 to G, and therefore tI! Sound device B does not sound. This allows only depolarizing current transformers to be detected easily and reliably.

Furthermore, if it is desired to detect the additivity, it is sufficient to invert the voltage signal r3V from the oscillator O8C and input it to the gate circuit SC.

In addition, the display method of sounding the alarm is the most practical and convenient method as there is no need to look at the meter, but there are other methods such as lighting a lamp or shaking the ammeter. Of course, it is possible.

In addition, when actually testing, as mentioned above, contact the primary terminal of the current transformer T, the L and secondary terminals, and 11 with the corresponding terminals of this device with clips or rods, etc., and check the sound level. This will determine whether it is right or not. Therefore, a test time of about 1 second is sufficient for each device, and the efficiency of the test can be greatly improved.

Furthermore, it goes without saying that the present invention can be widely applied not only to current transformers but also to transformers in general. In addition, in cases where the number of primary turns is greater than the number of secondary turns, such as in a transformer, a larger induced voltage can be detected by applying a square wave from the secondary winding side.
Do it like that.

In this case, the primary side in the above description refers to the secondary winding side, and the secondary side refers to the primary winding side.

〔Effect of the invention〕

As explained above, according to the present invention, a square wave is applied to the primary side of the transformer under test, and a voltage signal generated on the other side is generated in synchronization with the level of one of the square waves on the primary side. Since only one polarity signal is detected, and the display is deactivated based on the detection result, simply by connecting the device of the present invention to the transformer, the polarity can easily prevent the display from activating or deactivating. Once confirmed, a cold and reliable polarity test can be performed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention together with a current transformer under test, FIG. 2 is an operating waveform diagram of this embodiment, and FIG. 3 is a circuit diagram of the conventional kick method. SQ...square wave generator, E...constant voltage source, S...
Switch, O20...Oscillator, ■...Current transformer under test, D...Synchronization detection circuit, OP...Amplifier, G...
Gate circuit, B...Ir! Sound instrument. Applicant's agent, Fi Fuji-O Figure 1 (α); Se@re (b) Additive Figure 2 Ka Figure 3 Tesho ni Inu 1j Seizan April 20, 1986 1/1 Revision Director General Uga Doribu-dono 1 Showing the incident! n61 Patent Application No. 73731 2 Name of the invention Transformer polarity tester 3 Relationship with Irj who makes the amendment Patent applicant 1 "Electric Meter Certification Institute 4th Pll Person Marunouchi 3, Chiyo 111-ku, Tokyo: r l212-3 ° Ichizume Higashi S1ζ (211) 2321 representatives 6 N1 To positive -
ni-“J:-ri□-su-ru one shot 1111-(7) number~7
Target of Supplement 1

Claims (1)

[Claims] 1. A square wave generator that generates a square wave and supplies it to the primary side of the transformer under test, and either positive polarity or negative polarity induced in the secondary side of the transformer. A polarity tester for a transformer, comprising: a synchronous detection circuit for detecting only the voltage signal of the square wave in synchronization with one of the different levels of the square wave; and an indicator activated by the output of the synchronous detection circuit. 2. The transformer polarity tester according to claim 1, wherein the indicator is an alarm that emits a sound in response to the output of the synchronization detection circuit.