Voltage and Reactive Power Estimation for Contingency Analysis Using Sensitivities

Ruiz, Pablo A.; Sauer, Peter W.

doi:10.1109/tpwrs.2007.894868

Cited by 62 publications

(56 citation statements)

References 17 publications

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“…After a generator outage, the lost power needs to be temporarily provided by other generators, and a generator re-dispatch may then be needed if the outage cannot be restored quickly. For simplicity, all lost power is assumed to be picked up by the system slack bus by following [27] and many commercial software packages, e.g., PSSIE and PowerWorld. The N -2 cases include simultaneous outages of two lines, or one line and one generator.…”

Section: Constraint Satisfaction Problem Formulationmentioning

confidence: 99%

Corrective Line Switching With Security Constraints for the Base and Contingency Cases

Li,

Luh,

Michel

et al. 2012

IEEE Trans. Power Syst.

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Abstract-Following a line outage, the fast corrective operations of transmission line switching might be used to regain N -1 security of the system without generation re-dispatch or load shedding. The problem to find feasible switching operations can be formulated as a constraint satisfaction problem (CSP). Feasibility checking, however, is difficult since changes in load flows caused by line switching operations are discontinuous, and many contingency cases need to be examined. In this paper, DC flow is considered for simplicity, and variables include binary line statuses and continuous phase angles. Security constraints for the base case, N -1, and selected N -2 cases are formulated in a unified way by using a separate set of phase angles for each case. The problem is solved by using constraint programming (CP), and a tree search procedure is developed. Since it is time consuming to handle continuous variables in the tree search, only binary variables are branched on. Once reaching a leaf node where the topology is fixed, the constraints become linear DC flow feasibility conditions and are examined by solving a linear programming problem. Effectiveness of the method is demonstrated on IEEE 30-bus and US-bus systems.Index Terms-Constraint programming (CP), line outage, line overload, load flow feasibility, N -1 and N -2 contingency, transmission line switching.

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Section: Constraint Satisfaction Problem Formulationmentioning

confidence: 99%

Corrective Line Switching With Security Constraints for the Base and Contingency Cases

Li,

Luh,

Michel

et al. 2012

IEEE Trans. Power Syst.

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“…A bender-decomposition approach is used in [12] to incorporate a system security assessment. The method presented in [13] is used in this paper to find optimal system reinforcement which uses line loading and generation shift factors to calculate post contingency line flows and bus voltages [14]: The number of shift factor that should be calculated for the system parameters is a function of NAT NAL × . So, the less the number of candidate lines and transformers, the smaller the number of shift factors would be.…”

Section: Optimal System Reinforcementmentioning

confidence: 99%

A Cost/Worth Approach to Evaluate UPFC Impact on ATC

Rajabi-Ghahnavieh¹,

Fotuhi‐Firuzabad²,

Shahidehpour³

et al. 2010

Journal of Electrical Engineering and Technology

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-Available transfer capability (ATC) is a measure of the transfer capability remaining in a transmission system. Application of unified power flow controllers (UPFCs) could have positive impacts on the ATC of some paths while it might have a negative impact on the ATC of other paths. This paper presents an approach to evaluate the impacts of UPFCs on the ATC from a cost/worth point of view. The UPFC application worth is considered as the maximum cost saving in enhancing the ATC of the paths due to the UPFC implementation. The cost saving is considered as the cost of optimal application of other system reinforcement alternatives (except for UPFC) to reach the same ATC level obtained by UPFC application. UPFC application costs include the maximum cost of alleviating the probable negative impact on the ATC of some paths caused by implementing UPFCs. Optimal system reinforcement is used for systems with UPFCs to determine the aforementioned cost. The proposed method is applied to the IEEE-RTS and the results are evaluated through a sensitivity analysis. The cost/worth of UPFC application is also used to develop an index for optimal UPFC location and the results are compared with those of other indices. A comparison is finally made with the results obtained using an existing ATC allocation profit-based approach to determine UPFC application worth.

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“…The contingency analysis, which is a well-known function in power system planning and operation [11][12][13][14][15], is used later to predict the contingencies which make system violated and rank the contingencies according to their relative severity. An outage of a transmission line, capacitor bank or transformer may lead to over loads in other branches and sudden system voltage rise or drop.…”

Section: Introductionmentioning

confidence: 99%

Voltage stability analysis based on multi - objective optimal reactive power dispatch under various contingency

Amrane¹,

Elmaouhab²,

Boudour³

et al. 2017

ijeei

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An effective allocation of the reactive power in an electrical network aims generally to improve the voltage profile and to control transmission power losses. The present paper proposes the application of an efficient hybrid method combining two evolutionary search techniques. The technique is based on Particle Swarm Optimization (PSO) algorithm and Gravitational Search Algorithm (GSA) to solve the Optimal Reactive Power Planning (ORPP) problem for energy losses cost minimization of Algerian electric power system using the static Var Compensator devices (SVC). To ensure viability of the power system in contingency cases, various critical situations are simulated in order to prevent and prepare the power system to face such situations. The proposed program handles most changes that can occur in to the power system (heavy load, losing a large generator, losing a critical line …etc.). The proposed method is applied to solve the ORPP problem on the equivalent Algerian electric power system 114-bus. Moreover, the obtained results are compared, with PSO and GSA, separately. The results obtained by the proposed method show it's effectiveness for improving the reactive power planning problem. Index Terms: Optimal reactive power planning, Hybrid PSO-GSA, Stability Index, Equivalent Algerian electric power system. IntroductionThrough adjusting voltage generator, reactive power generator, transformer taps, and reactive power sources (capacitive or inductive banks, FACTS devices, etc.), the reactive power planning can reduce voltage deviations and active power losses. And in the same time maximizing voltage stability margin [1][2]. Since the generator reactive power, generator voltages, the transformer ratios and reactive power sources are continuous, the optimization problem is a nonconvex nonlinear programming problem (NLP). To solve such problem many conventional methods [3][4][5], like stochastic search methods [5][6][7][8][9][10][11] and hybrid conventional-stochastic methods [1], have been proposed.To insure the power system security, the OPRPP problem is associated with the contingency analysis problem. The contingency analysis, which is a well-known function in power system planning and operation [11][12][13][14][15], is used later to predict the contingencies which make system violated and rank the contingencies according to their relative severity. An outage of a transmission line, capacitor bank or transformer may lead to over loads in other branches and sudden system voltage rise or drop. This may lead to complete blackout. In this paper, three critical contingency cases are studied, these are: 1) Heavy load, 2) Lose a large Generator, 3) Lose a critical line. These cases are studied in a way to guarantee: i) The system stability after the increase of the power system load (voltage level, active and reactive power and load tap changer value are in the secure range), ii) The stability system maintainability after the outage of a large generator and a critical line, iii) a better location choice of the S...

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Voltage and Reactive Power Estimation for Contingency Analysis Using Sensitivities

Cited by 62 publications

References 17 publications

Corrective Line Switching With Security Constraints for the Base and Contingency Cases

Corrective Line Switching With Security Constraints for the Base and Contingency Cases

A Cost/Worth Approach to Evaluate UPFC Impact on ATC

Voltage stability analysis based on multi - objective optimal reactive power dispatch under various contingency

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