A New Procedure for Allocating Voltage Fluctuation Limits in Power Systems

Abstract

Procedures for determining the requirements for the connection of fluctuating installations in MV, HV, and EHV power systems are provided in IEC Technical Report 61000-3-7. The objective is to provide guidance to system owners/operators in order to help in the provision of adequate service for all connected customers. The approach is based on the allocation of the capacity of the system to absorb disturbances. The guidelines provided in the Technical Report can be difficult to apply in practice and are based on simplifying assumptions. A new approach is proposed in this thesis based on the concept of system voltage droop. It is based on the IEC Technical Report 61000-3-7 requirements and provides an effective theoretical foundation for the allocation process. In this procedure, the allocation of the system capacity to absorb disturbances depends on the users’ contribution to the system voltage droop. It is analytically proven that the method gives realistic emission limits to individual users without requiring unsupportable assumptions. Demonstrations of the proposed procedures are given utilizing a modified version of the IEEE 13-node distribution system and compared to results obtained using IEC Technical Report 61000-3-7. Furthermore, the proposed procedure is applied to a real MV rural network provided by Electricite de France and the results are compared to those obtained using the existing procedure in IEC Technical Report 61000-3-7