Contingency Analysis of Transmission Network Utilizing Voltage and Power Severity Index for Improving Reliability

The demand for electricity is growing exponentially day by day. Further, the penetration of renewable energy into the grid is also increasing. The increased load demand and penetration of renewable energy caused the power network to operate in the vicinity of stability limit. In view of this, outage of any transmission network element such as breaker, line etc. creates contingency in the network. Outage of a single transmission line has an impact on the remaining lines in terms of power flow, line losses etc. The bus voltages will also be affected in case of contingency in the network. In view of this, it is very crucial to study the behavior of the system network under contingency conditions. The effect of various contingencies on the network parameters is to be studied to initiate the possible corrective actions by the power system planners or transmission network operators. Sometimes, the critical contingency has the aggressive impact and the whole network may be partially or completely collapsed. Hence, the contingency planning will be very helpful to the systems operators for taking remedial actions.

This paper will highlight a methodology for contingency analysis of transmission networks. The contingency analysis is conducted by developing a new index namely power and voltage deviation (PVD) based index. It has been formulated by combining the two indices such as Active Power Severity Index (ASI) and Voltage Severity Index (VSI). The APS will represent the deviations of the active power flow through various transmission lines under different contingency scenarios. Further, the VSI will represent the variations of the voltage profile of the network considering different contingencies. The ranking of the different contingency scenarios is done according to the value of the overall PVD index. The highest value of PVD will indicate the most critical contingency and so on.

The developed contingency analysis scheme is experimentally validated through benchmark standard IEEE 5 bus and IEEE 14 bus systems. The experiment and simulation of contingency creation was conducted on MATLAB software and power flow algorithm was run for each possible contingency scenario and the experimental results are discussed. The developed contingency ranking and analysis scheme will be helpful to determine the critical contingency scenario. System planners can visualize the various network parameters through contingency analysis and anticipate the remedial actions accordingly. Hence, the proposed contingency analysis methodology will be useful for proper planning to avoid any tripping or network outages under contingency conditions. The contingency analysis will be also beneficial in terms of network reliability and asset management.