Voltage transformer on-site calibrator listening instrument calibration accuracy rate - Database & Sql Blog Articles

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

TP-IP4220CZ6 5V 0.35PF breakdown voltage 6V SOT

Photocoupler

Electromagnetic voltage transformers are widely used in electric energy metering devices of power plants and substations. The accuracy of their magnitude is directly related to the interests of power generation, power transmission and power supply. To this end, the voltage transformer tester should be used to periodically verify the electromagnetic voltage transformer. But in fact, as the voltage level increases, especially when the primary voltage of the electromagnetic voltage transformer exceeds 110 kV, the weight of the matching equipment of the conventional voltage transformer verification device such as a voltage regulator, a booster, a standard transformer, etc. It will increase exponentially, which will bring certain difficulties to the on-site verification work. In view of the problems existing in the traditional voltage transformer verification device, in the 1980s, Shanxi Machinery Research Institute proposed a method for calculating the high voltage voltage transformer error based on the error of the low voltage reference point and the variation curve of the primary excitation current, that is, "low high school height". "law.

It is worth mentioning that although the low-calibration high-voltage transformer field calibrator has been widely used in substation and power transformer voltage transformer verification sites, the state has not yet developed corresponding calibration specifications for such instruments, which is also very To a large extent, it has affected the promotion and application of such instruments. Therefore, it is necessary to study the calibration method of the instrument to ensure the accuracy and traceability of its magnitude.

1. Indirect comparison method calibration voltage transformer field calibrator

At present, indirect comparison is commonly used in China to complete instrument calibration. The specific method is: using a low-level high-voltage transformer field calibrator and a conventional voltage transformer differential pressure device, respectively, according to the wiring mode of Figure 1 and Figure 2 for a specific PT (ie, the comparison sample) instrument calibration, Take the difference between the two as the measurement result. However, in practice, due to the difference in the accuracy level, compensation type, stability, and actual load of the sample, it is difficult for different laboratories to achieve consistency in the calibration results of the same low-level high-voltage transformer field calibrator.