JPH07283050A - Transformer for amplifying meter - Google Patents

Abstract

PURPOSE:To provide a highly reliable transformer for amplifying meter by comparing zero-phase voltages, detected on the input and output sides at the voltage amplifying section, at a zero-phase voltage monitoring section thereby monitoring abnormality at the voltage amplifying section. CONSTITUTION:The transformer 21 for amplifying meter comprises a zero-phase voltage detection section 12 provided on the input side of a voltage amplifying section 4, a zero-phase detecting section 13 provided on the output side thereof, and a section 14 for comparing the output from the detecting section 12, 13 with each other and monitoring abnormality at the voltage amplifying section 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amplifying instrument transformer used for voltage measurement of electric equipment.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional amplifying type instrument transformer for only one phase. In the figure, reference numeral 1 is a main circuit conductor, 11 is a transformer for an amplification type instrument, and is composed of a main capacitor 2, a voltage dividing capacitor 3 and a voltage amplifying section 4.
24 is an output voltage, 6a and 6b are control cables for supplying the output voltage 24 to a load, and 8 is a computerized load,
In addition to the digital relay 9 and digital instrument 10,
It is composed of digital protective relays and instruments (not shown). Further, 7a and 7b are voltage input terminals of the load 8.

The voltage amplifying section 4 is composed of an electronic circuit, and the output voltage 24 thereof has a size matched with the input circuit of the load 8 such as the digital relay 9 and the digital meter 10.

[0004]

Generally, an electronic circuit is
The conventional amplification type transformer for transformers above is more susceptible to the induction current of commercial frequency, harmonics and switching surges propagating from the power supply system, and temperature and humidity. Measures were required in terms of reliability and durability. Therefore, it is an object of the present invention to provide a highly reliable amplifying instrument transformer by monitoring the abnormality of the voltage amplifying section.

[0005]

According to the present invention, an input-side zero-phase voltage detecting section for detecting a zero-phase voltage is provided on the input side of a voltage amplifying section of an amplifying instrument transformer, and the voltage amplifying section. Is provided on the output side of the output side zero-phase voltage detection unit for detecting the zero-phase voltage, and the output of the input-side zero-phase voltage detection unit and the output-side zero-phase voltage detection unit is compared, And a zero-phase voltage monitoring unit that monitors an abnormality of the voltage amplification unit.

[0006]

In the amplifying meter transformer of the present invention, the outputs of the input-side and output-side zero-phase voltage detectors provided on the input side and the output side of the voltage amplifying unit are compared by the zero-phase voltage monitoring unit. By doing so, the abnormality of the voltage amplification unit is monitored, so that the reliability can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of a transformer for an amplification type meter according to the present invention in three phases. In FIG. 1, 1
a, 1b, 1c are main circuit conductors, 21 is a transformer for amplifying type instrument, main capacitors 2a, 2b, 2c, voltage dividing capacitors 3a, 3b, 3c, voltage amplifier 4, input side zero-phase voltage detecting unit 12, It is composed of an output-side zero-phase voltage detector 13 and a zero-phase voltage monitor 14. 24a, 24b and 24c are three-phase output voltages, and 6a and 6b are output voltages 24a and 24.
control cable for supplying b, 24c to load 8, 7
Reference numerals a and 7b are voltage input terminals of the load 8. Further, 25 is an abnormal signal of the amplification type instrument transformer 21,
5b is a control cable for supplying to the failure display device 17, 16
Reference numerals a and 16b are abnormal signal input terminals of the failure display device 17. In addition, the failure display device 17 is a transformer 21 for amplification type instrument.
In addition to the above, it is a device for displaying an abnormality of a digital type protective relay or instruments not shown.

Next, the operation of the above device will be described. Main capacitors 2a, 2b, 2c and voltage dividing capacitors 3a, 3b, 3
The voltage obtained by dividing the voltage with c is input to the voltage amplifier 4 and the input-side zero-phase voltage detector 12. The voltage amplifier 4 amplifies the voltage up to a predetermined voltage and outputs the output voltage 24a, 24b, 24.
Output as c. The output voltages 24a, 24b and 24c are supplied to the input terminal 7 of the load 8 via the control cables 6a and 6b.
a and 7b, the magnitude of which is a voltage matched to the load 8. The output voltages 24a, 24b, 24c are
It is also input to the output-side zero-phase voltage detection unit 13. The input-side zero-phase voltage detector 12 and the output-side zero-phase voltage detector 13 detect the zero-phase voltage from the three-phase voltages. That is, if the three-phase voltages are Va, Vb, and Vc, and the zero-phase voltage is V0, then V0
= 1/3 (Va + Vb + Vc). Therefore, the zero-phase voltage V0 can be detected by vector composition of the three-phase voltages Va, Vb, and Vc. The input-side zero-phase voltage detected by the input-side zero-phase voltage detection unit 12 and the output-side zero-phase voltage detected by the output-side zero-phase voltage detection unit 13 are input to the zero-phase voltage monitoring unit 14. The zero-phase voltage detected by the output-side zero-phase voltage detector 13 is output as the output voltage 24d and is also input to the voltage input terminals 7a and 7b of the load 8 via the control cables 6a and 6b.

The zero-phase voltage monitoring section 14 monitors the abnormality of the voltage amplifying section 4 by comparing the zero-phase voltages output from the input-side zero-phase voltage detecting section 12 and the output-side zero-phase voltage detecting section 13. To do. That is, when an abnormality occurs in the voltage amplification section 4, a difference occurs between the input side zero phase voltage and the output side zero phase voltage, and the abnormality can be detected. When the voltage amplification unit 4 is normal, there is no difference between the input side zero-phase voltage and the output side zero-phase voltage, and it is recognized as normal. Further, the zero-phase voltage monitoring unit 14 outputs an abnormality signal 25 to the failure display device 17 in order to notify the abnormality of the voltage amplification unit 4 to the outside. The abnormality signal 25 is input to the abnormality signal input terminals 16a and 16b of the failure display device 17 via the control cables 15a and 15b, and the failure display device 17 displays the abnormality.

[0010]

According to the present invention, the zero-phase voltage detected at the input side and the output side of the voltage amplifying section of the transformer for amplifying type instrument is
By comparing with the zero-phase voltage monitoring unit, it is possible to monitor the abnormality of the voltage amplification unit, so that it is possible to provide a highly reliable transformer for amplification type instrument.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a transformer for an amplification type meter of the present invention.

FIG. 2 is a diagram showing an example of a conventional transformer for an amplification type instrument.

[Explanation of symbols]

 1a, 1b, 1c Main circuit conductors 2a, 2b, 2c Main capacitors 3a, 3b, 3c Voltage dividing capacitors 4 Voltage amplifying parts 6a, 6b Control cables 7a, 7b Load voltage input terminals 8 Load 12 Input side zero phase voltage detecting part 13 Output-side zero-phase voltage detection unit 14 Zero-phase voltage monitoring unit 15a, 15b Control cables 16a, 16b Abnormal signal input terminal 17 Failure display device 21 Amplification type instrument transformers 24a, 24b, 24c, 24d Output voltage 25 Abnormal signal

Claims (1)

[Claims] 1. An amplifying instrument transformer for amplifying a voltage obtained by dividing a main circuit with a capacitor in a voltage amplifying section to output a measured voltage, wherein the transformer is provided on the input side of the voltage amplifying section, An input-side zero-phase voltage detection unit that detects a zero-phase voltage, an output-side zero-phase voltage detection unit that is provided on the output side of the voltage amplification unit and that detects a zero-phase voltage, and the input-side zero-phase voltage detection unit And a zero-phase voltage monitoring unit that monitors the output of the output-side zero-phase voltage detection unit for abnormalities in the voltage amplification unit, and a transformer for an amplifier instrument, comprising: