A New Method for Voltage Measurement With Harmonic Voltage Amplification in the 10-kV Cable

The penetration rate of power electronic equipment and renewable resources in power system has rapidly grown recently, which may bring harmonic pollution. Therefore, the harmonic voltage measurement is much concerned. However, up to now, there is no special and accurate devices to online measure harmonic voltages in power system. Moreover, there is no one for medium-voltage cables, which may be the key points connected with renewable source. A new method for harmonic voltage measurement of 10-kV cable is proposed in this manuscript. A sensor integrated into the plug of a separable connector (SIPSC) is designed to measure the harmonic voltages in the 10-kV cable. The SIPSC has harmonic voltage amplification characteristics. The equivalent circuit and harmonic amplification characteristics of SIPSC are studied. An experiment is conducted to verify this method. A harmonic voltage source is used to supply voltages from the fundamental frequency to the 25th harmonic frequency. The fundamental and harmonic voltages are measured in the experiment. After comparing the fundamental voltages measured by SIPSC and the capacitive divider, the transfer ratio of the fundamental voltage for SIPSC is calibrated. Then, the capacitive parameters in the equivalent circuit of SIPSC can be calculated. Then, the harmonic voltages can be obtained based on equivalent circuit. The experiment and analysis show that the proposed method can amplify the harmonic voltages relative to the fundamental voltage. It is suitable for the measurement of high-order harmonic voltages.