GB/T 24841-2018 in English

1. Rated output and accuracy level

The standard value of rated output should be selected as: 1 VA, 2 VA, 5 VA, 10 VA. The accuracy level is divided into measurement (0.2 level), measurement and protection combination (0.5/3P) and protection (3P). The influence of ambient temperature and contamination should be considered for operation deterioration.

2. Insulation level and withstand voltage test

The insulation level requirements for capacitor voltage transformers are as follows:

• Rated short-time power frequency withstand voltage: 1200kV (RMS value)
• Rated lightning impulse withstand voltage: 2400kV (full wave peak), 2760kV (chopped wave peak)
• Rated switching impulse withstand voltage: 1800kV (peak)

3. Ferroresonance and transient response

Ferrosonance test is required to be carried out at 0.8U_pr, 1.0U_pr and 1.2U_pr voltages, and it is necessary to ensure that the secondary winding voltage peak recovery time does not exceed 2s. The transient response test needs to verify the voltage reduction characteristics of the protective winding.

1. Selection Guide

Choose a suitable CVT according to the actual use conditions, focusing on:

• Rated voltage matches the system nominal voltage
• Accuracy meets measurement and protection requirements
• Insulation level meets operating environment requirements

2. Installation and maintenance recommendations

- Ensure that the installation site is no more than 1000m above sea level. If it exceeds, special correction is required. - The creepage distance and shed structure of the external insulation part should be checked regularly.