VERIFICATION OF THE AUTONOMOUS VOLTAGE CONTROL FOR SVR BASED ON THE ADVANCED VOLTAGE-ESTIMATION CORRESPONDING TO THE VOLTAGE DROP PHENOMENON

Abstract

The reverse power flow from large-scale distributed generators (DGs) distributing medium-voltage power causes a voltage rise and a voltage drop owing to the phase-changes of the current. In particular, the node voltage changes nonlinearly during voltage drops, and it is difficult to control the line voltage with autonomous voltage control equipment, such as step voltage regulators (SVRs), because they assume linear voltage changes. Therefore, we had developed an advanced voltage-estimation method (simply referred to as the new method in this paper) for the control of the SVRs based on a simple calculation using measurements, including the unit line impedances in the distribution system. In this study, we fabricated a prototype new SVR using the new method and the conventional line drop compensator (LDC) method, which is a commonly used voltage control method. Through field tests with an experimental 6 kV distribution system, the prototype new SVR based on the new method was shown to be more efficient that the prototype new SVR based on the LDC method in terms of the total amount of the voltage deviation and the total number of tap switches of the SVRs.