In this paper, a probabilistic performance index (PI) has been developed to perform contingency selection and ranking. The results show that considering up to the second level contingency is satisfactory for both accuracy and computation time requirements. The results obtained constitute an essential basis for the analysis of power systems in terms of adequacy assessment and reliability evaluation. To substantiate the study results, comparison with other similar studies was performed.

Contingency selection and ranking for composite power system reliability evaluation

Contingency analysis is significant for power system protection. It is the analysis of a power system during non-functionality of equipment(s) or device(s). Contingencies in a power system can occur due to internal component failures or due to external factors like lightning and overloading of equipment. In this paper, contingency analysis has been done for an IEEE 30 bus system. Outage of generators, transmission lines and transformers have been carried out and the results are analysed. Under transmission line contingency, single line outage, double line outage and single circuit line with a compensator outage has been performed. Load flow before and after the contingency have been analysed using PSAT software. Performance indices have been used to rank the severity of each component's contingency. Performance index is given by the sum of active power performance index and voltage performance index. Similarly, a parameter known as Severity index is used to evaluate the effect on all transmissions lines in the power system due to outage of each component.

Contingency analysis of an IEEE 30 bus system

The security assessment is a fundamental task as it provides the knowledge about the system status in case of contingency. This helps in rapidly take the accurate action to maintain the system secure. In the present work, a Newton-Raphson load flow based approach is presented to perform contingency ranking by computing a voltage performance index (PI). The contingencies are classified in secure, insecure and critical classes and then the method proceeds in the decreased order of severity to rank them based on the PI value. The proposed method is applied to the IEEE 39-bus system in MATLAB environment by considering (N-1) contingency for different load conditions.

Newton-Raphson Load Flow Method for Voltage Contingency Ranking

As world is approaching towards the deregulated power system so daily load demand is increasing in unexpected way Voltage instability will occurs due to increment in load or with highly loaded system Security analysis of power system becomes the more imperative aspect to secure the system with concealed contingency So contingency ranking becomes the important procedure to rank the most severe line by evaluating the overall performance index (OPI) By incorporation of STATCOM in the system OPI value observed to reduce which may change the ranking of contingency but line becomes more severe This paper discusses about the severity of line by ranking the contingency with and without STATCOM Newton Raphson load flow analysis is perform to evaluate the voltage and active power performance index IEEE 24 bus system (RTS-79) is used for the testing of security by ranking the most severe lines using MATLAB

Contingency Ranking for Security Analysis of Power System Network with Incorporation of STATCOM

In this paper, the new approach for the transmission reliability cost allocation (TRCA) problem is proposed. In the conventional TRCA problem, for calculating the contribution of each user (generators & loads or contracts) in the reliability margin of each transmission line, the outage analysis is performed for all system contingencies. It is obvious that this analysis is very time-consuming for large power systems. This paper suggests that this calculation should be done only for major contingencies. To do this, at first, the contingency filtering technique (CFT) is introduced based on the new economic indices that quantify the severity of each contingency to determine the critical contingencies. Then the results of contingency filtering are used in the TRCA problem. The simulation results are reported for the IEEE 118-bus test system. The obtained results show that by application of CFT in TRCA problem, the simulation time is greatly reduced, but the percentage of error remains within an acceptable limit.

http://ijeee.iust.ac.ir/files/site1/user_files_5e3495/elecmohsen2002-A-10-262-4-de2a413.pdf

Transmission Reliability Cost Allocation Based on Contingency Filtering by Economic Indices in Large Power Systems

As power demand is increasing day to day life loading on present power system is also increasing. As a result voltage instability occurs with heavily loaded system. So power system security becomes one of the important aspect where operational engineers need to estimate the unseen contingency. So contingency screening and ranking is one of the important procedure for on line system security assessment. In this paper contingency screening and ranking is done by fast decoupled load flow by using performance index i.e., active power (PI p ) and voltage performance index(PI v ) for the line outage of the given power system. Ranking is based on overall performance index (PI) i.e., summation of active power performance index(PIp) and voltage performance index (PIv) the highest value of PI ranks first and proceeds in descending order for further ranking. The proposed work is simulated on IEEE 5 bus system on MATLAB environment.

Tegala. Srinivasa Rao

Papers

Power system contingency ranking using fast decoupled load flow method