PEVT和AEVT在实验室和在线运行状态下误差特性比较研究

Research on error characteristics comparison of PEVT and AEVT under the conditions of laboratory and on-line operation

PEVT和AEVT是目前在电网投运的两类典型EVT,但其投家运前均需在现场对误差特性进行二次定标。为了研究EVT实验室和在线运行状态下的误差特性,选取业内两个主流厂家的PEVT和AEVT试品,对其开展了实验室和在线运行为期一年多的误差特性比较研究。结果表明,测试环境对PEVT比差的影响低于0.05%,实验室温度特性在-40℃^+53.5℃温度范围内,比差变化最大达4.3%;现场运行时的温度特性在温度范围-20℃~40℃之间,比差的变化为0.55%。AEVT对测试环境敏感,比差从实验室时0.03%、现场离线为0.18%,现场在线变为0.36%;但其温度特性较好,实验室温度特性在-40℃^+63℃的温度范围内,比差变化为0.21%,AEVT现场温度特性在温度范围-20℃~40℃之间,比差的变化在0.1%以内。另外,EVT的温度特性对温度变化梯度敏感,现场实际运行时的温度特性优于实验室的温度特性。

PEVTs and AEVTs are currently two kinds of typical EVTs in operation of power grid, but they would be required to calibrate error characteristics again before the operation. In order to research error characteristics of EVTs in three states of laboratory and field off-line and on-line operation, PEVT and AEVT samples from two mainstream manufacturers were selected to carry out the comparative study of error characteristics. The results show that the effect of the testing environment on ratio error of PEVT is less than 0.05% ; however, the variable quantity of ratio error in laboratory is 4.3% with the temperature in - 40 ℃- ＋53.5 ℃ and 0.55% in on-line operation in the temperature range of - 20℃ ~ 40 ℃. The ratio error of AEVT is sensitive on the test environment with the error from laboratory 0. 03%, off-line scene 0. 18% and on-line operation 0.36% ; but the variable quantity of ratio error in laboratory is 0.21% within the temperature range of - 40 ℃ ~ ＋ 63 ℃ and 0.1% in on-line operation within the temperature range of - 20 ℃ ~ 40 ℃. In addition, the temperature characteristics of EVTs is sensitive to temperature gradient, and the temperature characteristic in on-line operation is better than in laboratory.