Comprehensive Dynamic Reactive Power Planning for Transmission Stability Enhancement

  • Ahmad Tahboub

Student thesis: Doctoral Thesis

Abstract

High concentrations of low inertia induction motor loads can impose stress on transmission and distribution systems, leading to voltage instability in some situations. Properly sized and coordinated reactive power sources will provide for improved operation. This work presents a comprehensive dynamic VAR planning strategy for finding the optimal mix (type, size and location) of dynamic shunt reactive compensation devices taking into account their different costs and dynamic behavior. The planning strategy is subject to satisfying steady-state, dynamic and transient performance criteria such as fault-induced delayed voltage recovery (FIDVR) limits, as well as criteria related to single (N-1) contingency and load disturbance events. Shunt reactive power compensation devices considered include mechanically-switched capacitor banks (MSCB), static VAR compensators (SVC) and static synchronous compensators (STATCOM). The proposed strategy employs a large number of multi-timescale time-domain simulations suitable for use with high performance computing (HPC) clusters with a high degree of parallelization to circumvent the inherent intractability of the dynamic VAR planning problem. A genetic algorithm (GA) is employed to solve the mixed-integer nonlinear programming (MINLP) formulation using parallel computation capabilities after simultaneous/full discretization. The method is applied to the New England IEEE 39-bus system in a worst-case scenario loading condition (e.g. peak summer load) with assumed high penetration of induction motors. A comprehensive study and cost/benefit analysis shows that performance enhancement and significant cost reduction can be achieved using an optimum combination of various shunt compensator technologies, and computational speedup using HPC is quantified. The study avoids candidate bus restrictions and sensitivity analysis prior to optimization and thus better explores the solution search space to obtain lower cost solutions. Afterwards, an investigation of the ability of voltage-sourced converter (VSC) based VAR compensation, such as STATCOM, to reduce generator power swing in the fault-on condition is undertaken to exploit the voltage-independent STATCOM characteristics. One goal of the multi-objective formulation is to minimize total kinetic energy deviation in the short-term timescale, where separation between load-driven and generator-driven stability problems is rarely well-defined. It is shown that hybrid static/dynamic VAR installations can reduce the investment cost of the substantial additional required VAR capacity.
Date of AwardMay 2017
Original languageAmerican English
SupervisorMohamed El Moursi (Supervisor)

Keywords

  • Reactive Power
  • Electric Transmission Systems
  • Power Compensators
  • Induction Motors
  • Compensator Technologies.

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