The power frequency parameters of high-voltage transmission lines (referred to as line parameters) are one of the fundamental data required for the safe operation of power systems, affecting system stability, operation modes, power flow calculation, relay protection setting, voltage regulation, and reactive power compensation, among others. Therefore, line parameter testing is necessary before newly erected lines are put into operation, after partial reconstruction of operating lines, or when significant changes occur in the operating environment along the route (such as the addition of nearby new lines).
The method and principle of the high-voltage line power frequency parameter tester are not complicated, but in practice, correct results are often not obtained due to electromagnetic interference. Currently, the engineering method for measuring these parameters still involves applying power frequency voltage to the line under test and using ammeters, voltmeters, wattmeters, frequency meters, and other measuring instruments, reading the scales of each meter and performing corresponding calculations to obtain the parameter values. This traditional measurement method has many problems, such as heavy measurement equipment, cumbersome operation, many meters used, complex wiring, large workload, and susceptibility to errors. To eliminate interference during tests, methods such as using higher power supplies and changing phases are often employed, which complicates the testing. Additionally, on-site, the wiring of multiple transformers and instruments is complex, multiple people read meters, and the allowable working time is often short, requiring significant manpower and resources, which is time-consuming and laborious, and does not meet the simple and convenient requirements of field testing.
The frequency-shift line parameter tester is an integrated measuring instrument carefully developed by our company to address the above drawbacks and facilitate on-site measurement of power frequency parameters of high-voltage transmission lines. It is mainly used to measure and calculate parameters such as electromagnetic induction voltage, positive-sequence impedance, zero-sequence impedance, positive-sequence capacitance, zero-sequence capacitance, mutual inductance reactance, and coupling capacitance between two transmission lines for overhead lines or cable lines with voltage levels of 35kV and above.
This instrument integrates functional components such as test power supply, frequency-shift generator, automatic control, data acquisition and calculation, display and printing. Through advanced anti-interference technologies such as frequency shifting and digital filtering, it can conveniently, quickly, and accurately measure relevant parameters of transmission lines, simplifying the test power supply, measuring instruments, and other equipment required by testers, effectively eliminating the influence of power frequency signals on measurement, and providing great convenience for field testing.
