Understanding the Role of Forecast Errors on the Effectiveness of Operating Envelopes

To better integrate the growing number of residential solar PV and batteries, Australian distribution companies are preparing to implement Operating Envelopes (OEs). OEs are time-varying export limits at the customer’s point of connection. OEs allow distribution companies to operate their low voltage (LV) networks within technical limits while enabling customers to export more and, thus, make the most of their investment. However, to accurately calculate OEs not only extensive measurements are needed but also their corresponding forecast. This also means that forecast errors may jeopardize network integrity if OEs are fully utilized. This paper investigates the impact of forecast errors on the effectiveness of OEs. To understand it, this paper evaluates its effects on customer voltages and transformer utilization. The evaluation focuses on the impact of different levels of errors in the forecast of three key parameters used to calculate OEs: active power, reactive power, and voltages at the transformer. A case study of a real Australian LV network with 8 customers, based on actual measurements and a validated electrical model, shows that transformer voltage forecast is the most critical. Small underestimations lead to overestimations of the OEs which mean that customers could exceed voltage limits.