【Abstract】 Capacitor voltage transformers (CVT) are widely used in measurement, protection and other aspects in the line of 110kV and above because of their high electric strength and large insulation margin. With the separation of factories and networks, the accuracy of the energy metering devices at the gateway has received increasing attention. However, due to its own structural characteristics of the CVT, its error results under different working conditions often differ greatly. Firstly, the article establishes the equivalent model of CVT, and analyzes its error from the aspects of its structural principle, measurement methods, external environment and so on, and obtains the error trend. Secondly, taking the CVT used in Zhefu project as an example, the factory error test, transfer error test and online error test data are compared and the correctness of the theoretical analysis is verified. By analyzing and verifying the trend of CVT error, it provides guidance for on-site handover test and on-line error calibration test, and improves the reliability of CVT error measurement data.
【Authors】 : 【 China Electric Power Research Institute 】 【 State Grid Hubei Electric Power Company Electric Power Research Institute 】【 Wuhan Tuopu United Power 】
[Keyword] : Capacitive Voltage Transformer accuracy level error limit factory test handover test
HGQC-H capacitive voltage transformer on-site calibrator [ Wuhan Tuopu United Power ]
Aliases: Capacitive Voltage Transformer Error Analyzer Capacitor Voltage Transformer Field Error Tester GIS Voltage Transformer Field Calibrator Capacitive Voltage Transformer Low School Field Tester
The error detection of capacitive voltage transformers (hereinafter abbreviated as CVT) mostly adopts the method of series or parallel resonance boosting. The test wiring is complicated, the variety of equipment required is large, and the equipment is very heavy and it is very difficult to handle on site. HGQC-H Capacitor Voltage Transformer Low School Height Field Tester [ Wuhan Tuopu United Power ] (hereafter referred to as the tester) has the actual error under the condition of measuring high voltage under low voltage condition, and the single device can satisfy On-site capacitance voltage transformer error measurement . Can cover the internal standard voltage transformer part Ratio range 35kV/100V ---- 500kV/ √3 /100V/ √3
Ratiometric measurement of a power capacitive voltage transformer. The instrument was designed with some new ideas in mind and some new techniques were adopted. Including different frequency power technology, common platform technology, voltage simulation load, internal high accuracy voltage transformer and self-boosting power supply. Users feel more convenient, faster and more efficient when using the instrument.
HGQC-H Capacitor Voltage Transformer Low-high Field Tester [ Wuhan Tuopu United Power ] According to the CVT equivalent circuit, measurement techniques such as inter-frequency measurement, low-voltage extrapolation, and simulation load are used; the instrument absorbs the computer and high precision Signal sensors, digital signal processing, and highly stable variable frequency power supplies measure CVT errors at lower voltages. The measurement errors fully meet the accuracy requirements of national regulations.
main feature
1. Without the need of boost source, standard transformer and load box, the ratio difference and angle difference of field test CVT can be realized. The test result fully meets the requirements of national transformer verification procedures. 2, with polarity, change ratio, wiring check function. 3. The temperature and humidity can be measured so that the user can understand the working environment at any time. 4. A single tester can complete the measurement of CVT errors. 5. It has the characteristics of fast test, large amount of processing information and large storage capacity. 6. The tester adopts frequency conversion technology, digital processing, and strong anti-interference ability on the spot. 7. The maximum voltage of the test process does not exceed 3kV and various protection measures are taken to ensure personal safety and equipment safety and reliability. 8. The test process is simple to operate.
Technical Parameters
1. Ambient conditions: Temperature: (5~40) ° C Relative Humidity: <80% (25 ° C) Altitude: <2500m Power frequency: 50 ± 0.5Hz 2. Voltage transformer type under test: Capacitive voltage mutual inductance Device 3. Accuracy of error measurement: 0.05% 4. Partial pressure ratio measurement accuracy: 0.5% 5. Internal standard voltage transformer part: a, variable ratio range:
35kV/100V, 35kV/ 
/100V/ 
66kV/100V, 66kV/ 
/100V/ 
110kV/100V, 110kV / 
/100V/ 
220kV/100V, 220kV/ 
/100V / 
500kV/100V, 500kV/ 
/100V / 
b, accuracy level: 0.02%
6. Dimensions (mm): 460 '360' 210
7. Weight (Kg): 25.0
