Field Verification of an Autonomous Anti-Islanding Scheme of a Microturbine Inverter-Based Generator

Abstract

Recent regulations introduced in Alberta, Canada, have resulted in a direct impact on the oil and gas industry. In particular, venting, flaring and incinerating natural gas has become an intolerable practice with small quotas and high penalties. This, coupled with the mandate to decommission the coal-fired base generation has stimulated the proliferation of Distributed Energy Resources (DERs). Many oil companies are employing gas-fired DERs to offset their byproduct gas produced during oil extraction processes. But the integration of DERs to distribution grid requires addressing concerns and requirements. Among these requirements, health and safety hazards shall be eliminated or minimized. In this industry, islanded operation of a DER is considered a safety hazard and is not permitted by the electric utility, safe in exceptional cases. The standard method to avoid islanded operation is the Direct Transfer Trip (DTT). In very exceptional cases, however, the utility may accept an alternative method. This paper addresses one of these methods and presents measurement data collected during the commissioning of one of these DERs. The case study demonstrates the effectiveness of an inverter-based active anti-islanding scheme and its adherence to applicable DER interconnection standards. It also describes the current application scenarios where the electric utility may elect to accept these schemes in lieu of the standard DTT.