Book Description

The management of power systems has become more difcult than earlier because power systems are operated closer to security limits, environmental constraints restrict the operation of transmission network, the need for long distance power transfers has increased and fewer operations are engaged in the supervision and operation of power systems. Voltage instability has become a major concern in many power systems and many blackouts have been reported, where the reason has been voltage instability. Voltage stability is concerned with the ability of the power system to maintain acceptable voltages at all system buses under normal conditions as well as after being subjected to a disturbance. Thus the analysis of voltage stability deals with nding the voltage levels at all buses in the system under different loading conditions to ascertain the stability limit and margin. Several works have been conducted recently for the prediction of voltage stability and collapse based on the steady state analysis; some of these are focus on static voltage stability analysis with the use of instability measuring indicators. In the book IEEE 30 bus and real time AP State 124 bus test systems are simulated using MATLAB Programming and MIPOWER, POWERWORLD Software's. Contingency ranking has been made for the n-1 contingency case and identied severe most contingency based on various voltage stability indices. The optimal placement of shunt compensator is identied using P-V curves, Lindex and Voltage Collapse Proximity Index (VCPI) - indices.The optimal placement is also obtained using FVSI and LLI (Novel Proposal) and compared with previous methods.The optimal size has been obtained by converting the critical bus into voltage controlled bus using ctitious generator, which generates only reactive power for maintaining that bus voltage nearly equal to 1.0 p.u. The test results have been compared with the reactive power loss based iterative solution. The subsequent chapter deals with the optimal placement of Series compensator. The minimum of Lmn and FVSI are identied for the severe most contingency for optimal placement of series compensator. The control algorithm is developed for nding optimal size of the series compensator by assuming initial value for the degree of compensation and suitable step size. The optimal results have been presented using the proposed algorithm. The comparisons of test results have been presented using xed shunt compensator and SVC for IEEE 30-bus test system. Lastly the control algorithm is developed for nding optimal size of the series and shunt compensators for their coordination control. By using xed series compensator value equal to (10 to 20% it is based on case) and tuning is done for the shunt compensator by assuming initial value of the shunt compensation and suitable step size based on Reactive Power Loss of the system.The optimal results have been presented using the proposed algorithm of coordination control in which series controller is acting as supplementary controller and shunt controller as Master controller.The comparison of test results have been presented for all type of compensators viz. shunt, series and coordination control for IEEE 30-bus test system.