Quantifying the impact of supply frequency adjustments for DER control on consumer appliances

Abstract

An unexpected challenge facing network operators due to high penetration levels of small-scale solar photovoltaic occurs when diesel backup generators are used to maintain supply to small network islands during maintenance. Most grid-connected small-scale solar inverters in Australia have no means of grid control and it is uneconomical to individually isolate each device within premises. Taking advantage of out of frequency protection settings of the inverters to disable output of distributed generation is one potential mechanism Network Service Providers are considering when operating the diesel generator. This is achieved by operating the diesel generation at a frequency above or below the inverter out of frequency settings. This paper investigates the potential impact of this operation on other connected loads, specifically 44 domestic appliances. The impact on electrical parameters RMS current, real and reactive power, displacement power factor, and current total harmonic distortion, as well as relevant actuation and operation are monitored for operating frequencies selected by the Network Service Providers to ensure solar inverters will either disconnect from or will not connect to the network, and for frequency variations expected on the modern network. The resulting parameters for each appliance are reported with only minor maloperation found for one of the appliances during testing.