Improving the Cross-Border Activation of the Regulating Reserve to Enhance the Provision of Load-Frequency Control

Abstract

This paper presents the Cross-Border activation of the Regulating Reserve (CBRR) between participating Control Areas (CAs), which is being developed to reduce the costs of balancing energy. The main objective of the CBRR is to activate the regulating reserve in participating CAs, to release the regulating reserve and to reduce the balancing energy as part of the safe operation of the power system. However, the classic CBRR includes a frequency term and, therefore, inherently affects the frequency response of the participating CAs, which is not discussed in the literature. In this paper, the impact of the classic CBRR on frequency quality and the provision of Load-Frequency Control (LFC) is thoroughly evaluated with dynamic simulations of a three-CA test system and an eigenvalue analysis of a two-CA system. It is clearly demonstrated that the classic CBRR reduces the damping of the entire power system. Therefore, a modified implementation of the classic CBRR is presented, and a modified CBRR is proposed, which has no impact on the system's eigendynamics. Furthermore, the results of the dynamic simulations confirm that the frequency quality can be improved by the classic CBRR, although there are also cases where it can deteriorate. However, the modified CBRR improves the frequency quality in all cases. The modified CBRR also improves the indicators for the provision of LFC compared to the classic CBRR. Moreover, the modified CBRR reduces the unintended exchange of energy and the demand power, thus increasing the financial effects of the CBRR's activation. INDEX TERMS Balancing energy, Cross-Border activation, eigenvalue analysis, Load-Frequency Control, regulating reserve. NOMENCLATURE N Number of participating CAs. ACE i , ACE i , ACE * i

Evaluation of the Simultaneous Operation of the Mechanisms for Cross-Border Interchange and Activation of the Regulating Reserves

“…The results confirmed the conclusions in [20][21][22][23], where the INP and CBRR were analyzed separately. The results of the step change of load and the random load variation confirmed that the impact of the INP and CBRR on frequency deviations has no unambiguous conclusions.…”

“…In [21], the impact of INP on power-system dynamics is shown and an eigenvalue analysis of a two-CA system is conducted. The impact of CBRR on the power-system dynamics is shown in [23], and a modified implementation of the CBRR is proposed that has no impact on the system's eigendynamics. This article extends these earlier results with an in-depth evaluation of the simultaneous operation of the mechanisms for cross-border interchange and activation of the RRs, which was not studied before.…”

“…Moreover, only CAs with different signs of demand power, i.e., sign(P di ) = sign(P dj ), can net the demand for balancing energy. If two or more cooperating CAs are "short", then CBRR is used instead of the INP and vice versa [23]. Therefore, the cooperating CAs must be "short" and "long" in order to net the demand power through the INP.…”

“…Note that a virtual tie-line means an additional input of the controllers of the cooperating CAs that has the same effect as a measuring value of a physical interconnector and allows exchange of electric energy between the cooperating CAs [1]. The main objectives of the INP optimization are given in [20,21], whereas the main objectives of the CBRR optimization are given in [22,23]. There has been a surge in the application of machine learning and statistical framework to solve similar problems focused in this paper.…”