Voltage control is usually performed with an on-load tap changing transformer (OLTC). The OLTC’s controller gets voltage measurement values from the regulation point. Based on those values, it sets the correct tap position, so the voltage is within limits. When the distance between voltage measurements and the transformer is long, there is a chance that a fault may occur during data transmission, so we no longer know voltage values at the regulating point. That means the controller cannot set the correct tap position. The goal of the research was to find options for voltage control when we lose the connection to measured voltage values.
Literature showed two different approaches that we tried: line drop compensation and calculation of the voltage drop. We also tried the PQ method.
Line drop compensation and calculation of the voltage drop neglect capacitance in most cases, which, causes too much deviation from wanted result.
The PQ method showed us accurate and adequate results.
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