A Static Voltage Security Region for Centralized Wind Power Integration—Part II: Applications

Abstract

Abstract:In Part I of this work, a static voltage security region was introduced to guarantee the safety of wind farm reactive power outputs under both base conditions and N-1 contingency. In this paper, a mathematical representation of the approximate N-1 security region has further studied to provide better coordination among wind farms and help prevent cascading tripping following a single wind farm trip. Besides, the influence of active power on the security region is studied. The proposed methods are demonstrated for N-1 contingency cases in a nine-bus system. The simulations verify that the N-1 security region is a small subset of the security region under base conditions. They also illustrate the fact that if the system is simply operated below the reactive power limits, without coordination among the wind farms, the static voltage is likely to exceed its limit. A two-step optimal adjustment strategy is introduced to shift insecure operating points into the security region under N-1 contingency. Through extensive numerical studies, the effectiveness of the proposed technique is confirmed.

A Static Voltage Security Region for Centralized Wind Power Integration—Part I: Concept and Method

“…The proposed voltage security region is the basis for an N-1 voltage security region to provide better coordination among wind farms and help prevent cascading tripping when a single wind farm is tripped. Further analysis on the voltage security region under N-1 contingencies will be presented in Part II [24].…”

“…Therefore, we will put emphasis on the calculation of normal voltage security region in the following work, and the N-1 security region will be fully studied in part II [24].…”

Review of Challenges and Research Opportunities for Voltage Control in Smart Grids

“…It is thus more reasonable for wind farms to take preventive controls [2]. The boundary of voltage security region (VSR) is computed by an approximate linearization method [24], [25]. Then a robust VSR [26] is proposed in order to consider wind power forecast error.…”

Dynamic reactive power reserve optimisation in wind power integration areas

“…Therefore, it is important for wind farms to take preventive control and reserve enough dynamic reactive power sources in normal conditions to response to the disturbances and contingencies. The static voltage violation before an N − 1 contingency is the most important factor leading to cascading failure, thus, in order to prevent the WTGs from experiencing cascading trip faults, a static voltage security region (VSR) has been proposed in some previous studies [19][20][21][22] and a more practical static autonomous voltage security region (AVSR) was proposed in previous work [23] for wind automatic voltage control (AVC) systems, because these can be controlled independently by wind farms without considering the operational details of other wind farms [18,24]. The definition of the AVSR in wind power grids is as follows: If the control centre controls the point of common coupling (PCC) substation (as shown in Fig.…”