Design, Construction, and Field Evaluation of an Intelligent Solid-State Voltage Regulator for Voltage Profile Improvement in Low-Voltage Distribution Networks

Voltage drop at the end of low-voltage (LV) feeders is one of the major operational challenges in distribution networks, often leading to reduced power quality and malfunction of sensitive loads. Conventional distribution transformers equipped with mechanical tap changers are not suitable for this purpose due to their high cost, slow response, and the need for network de-energization during operation. In this paper, a low-power Solid-State Voltage Regulator (SSVR) with a simple structure and instantaneous voltage compensation capability is designed, implemented, and experimentally validated. The proposed prototype, rated at 15 kVA, can maintain the output voltage within ±3.7% of the nominal value of 220 V, while preserving the power quality. To validate the regulator’s performance, simulations were first carried out on the IEEE Low Voltage (IEEE-LV) Test Feeder. The original IEEE 906-bus LV feeder model was reduced to a 116-bus equivalent network with 55 loads using standard feeder reduction techniques to enhance computational efficiency. Three single-phase SSVRs were optimally located on phases A, B, and C to compensate for the most critical voltage drops. Simulation results showed that the average voltage drop decreased from 0.0506 p.u to 0.0338 p.u, and the total power loss improved by about 2.3%. Subsequently, the fabricated prototype was installed and tested on a rural feeder of the Lorestan Power Distribution Company (Iran). Field measurements confirmed the regulator’s effective operation in stabilizing the output voltage and mitigating voltage fluctuations under real conditions. The obtained results demonstrate that the proposed SSVR provides a cost-effective, fast, and reliable solution for voltage profile improvement in low-voltage distribution networks.