Distributed HVDC Emergency Power Control; case study Nordic Power System

TL;DR

This paper evaluates the use of HVDC-based Emergency Power Control in the Nordic Power System to improve frequency response during large disturbances, emphasizing the distribution and effectiveness of EPC.

Contribution

It introduces a methodology to assess HVDC EPC distribution and performance in a detailed power system model, considering nonlinear system behavior.

Findings

EPC can effectively limit frequency deviations during disturbances.

Distribution of EPC impacts the frequency nadir and system stability.

The methodology accounts for nonlinear system responses.

Abstract

Frequency Containment Reserves might be insufficient to provide an appropriate response in the presence of large disturbances and low inertia scenarios. As a solution, this work assesses the supplementary droop frequency-based Emergency Power Control (EPC) from HVDC interconnections, applied in the detailed Nordic Power System model. EPC distribution and factors that determine the EPC performance of an HVDC link are the focus of interest. The main criteria are the maximum Instantaneous Frequency Deviation and used EPC power. The presented methodology is motivated based on the theoretical observation concerning linearized system representation. However, the assessed and proposed properties of interest, such as provided EPC active and reactive power, their ratio, and energy of total loads and losses in the system due to the EPC, concern highly nonlinear system behavior. Finally, based on the obtained study, remarks on the pragmatical importance of the EPC distribution to the frequency nadir limitation are provided.