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A new fast static security analysis algorithm, based on the interval analysis theory and probability theory, is proposed to improve the efficiency and accuracy of security analysis during power network interaction. In this paper, the characteristics of network interaction and uncertainty in the interaction process are illustrated firstly. After that the dimension reduction technique is employed in...
System Protection Schemes (SPS) are considered as an effective tool for enhancing the resilience of the power system towards rare contingencies. The validation of SPS is difficult by using conventional SCADA data due to its inherent low scan rate and skewedness. Under such condition, Synchrophasors has been found to be better suited for performance evaluation SPS and review of its design. This paper...
The electric power system is one of the most complex engineered systems. It is, thus, a challenge to design a market that is efficient, transparent, and provides the proper incentives to market participants. Existing market models employ constraint relaxations, which enable various constraints to be relaxed (violated) for a high penalty price. This paper examines the practice of allowing transmission...
In restructured power systems, generation and commercialization activities became market activities, while transmission and distribution activities continue as regulated monopolies. As a result, the adequacy of transmission network should be evaluated independent of generation system. After introducing the constrained fuzzy power flow (CFPF) as a suitable tool to quantify the adequacy of transmission...
Increasing consumer choices and market options in the power market necessitate a more resilient grid operation. Security level indication based on the desired risk index and thus a risk-based security constrained optimal power flow is described and simulated in this paper. It highlights the possibility of giving a choice of security level to a consumer area and also presents the computation of risk...
The paper proposes a new method to assess the grid risk based on cascading failure model. Compared with the traditional N-1 or N-2 method, the method considers all factors that affect the process of cascading failure, including the trip of overloading line, the action of automatic security equipment and the hidden failure of line protection. And the paper emphasizes on the multiple hidden failure...
Voltage Stability and Voltage Security are considered as important concerns in power system planning and operation. To provide reliable, secure and stable electrical power to the customers, is the main task of power system engineer. To meet these requirements simultaneously, the power system is to be operated closer to its stability limits which cause more stress on the power system. Therefore, a...
Electrical transmission grids are planned to be in compliance with redundancy specifications, such as the deterministic (N-1) criterion. Due to increasing power transmission, the grid components experience a higher utilization rate. One essential issue of transmission grid planning is the necessity of the grid enforcement and the dimensioning of its components. Considering a similar level of grid...
Network contingency analysis for power system operation, is considered as the most vital concern of its security appraisal. Present days, on-line security assessment is carried out by contingency ranking, with the help of various computing techniques. One of the iterative methods is Newton Raphson power flow method for obtaining the magnitudes of different parameters. The aim of contingency ranking...
Today's Power system is more complex and consequently it would lead to less security. To meet the demand and better security levels with existing transmission lines, the Flexible AC Transmission System (FACTS) devices are one of the alternates. In this paper a Newton Raphson(NR) algorithm was developed to find out the best operating point of a Static Var Compensator(SVC) for the enhancement of system...
In this paper, we study on evaluating physical education teaching quality based on the entropy model. The entropy model is a measure of the uncertainty associated with a random variable, which is a powerful tool in many research fields. Next, a physical education teaching quality evaluation method is designed by obtaining the maximum information entropy based on the index systems, which include 12...
A cascading trip of distance relay due to overload caused by another line tripping has been observed in some blackouts. Preventing such an unwanted trip of a distance relay could contribute to blackout prevention. In this paper, a new index (PVI) for evaluating vulnerability from distance protection viewpoint is proposed which indicates the risk level of a distance relay that can lead to multiple...
The constantly improvement of communication help the technology of WEB services find its way to the power dispatching system. Gived WEB services is actively populized and applied in this field, it is necessary to develop a series of application sofewares for power system analysis based on WEB platform. Static security analysis plays an important role in power grid's security analysis. However, with...
Transmission line congestion in electricity market is lead to increase the energy cost and change in local marginal prices. So, it is probable that the market power is manifested. Market power may prevent the full competition in Electricity Market. Moreover, in this condition, with operating of power system in its boundary conditions, the system may be damaged and the security of the system may be...
Transmission power flows are dependent on physical laws. Transmission system expansion planning (TSEP) of a transmission utility in the deregulated environment becomes complex. It has been identified that utilities mainly perform planning to serve the needs of their own customers within a defined service territory. However, there needs to be a coordination with the neighboring transmission utilities...
Unified power flow controller (UPFC) is a powerful FACTS device. After analyzing the disadvantages of indexes used to evaluate the impact of UPFC on power system security at present, this paper proposes a new index system with considering the mechanism of UPFC working in power system. Then the reliability model of UPFC based on real-time operating conditions is established, and the probabilistic assessment...
An important number of contingencies simulated during dynamic security assessment do not result in unacceptable values of state variables, due to their small influence on system operation. Their exclusion from the set of contingencies to be simulated in the security assessment would achieve a significant reduction in computation time. This paper defines a critical contingencies selection method for...
This paper presents a simple and efficient heuristic method for transmission network expansion planning (TNEP), which can take care of uncertainties in load specifications and also the formidable security constraints. The proposed heuristic method is based on a DC power flow based compensation approach to simulate single/double line modifications arising out of a candidate line addition and an outage...
In this paper a decision tree method has been proposed for optimal PMU placement for voltage security assessment. In the proposed method the voltage security index for every operating point is calculated off-line. As a result, the system security status is determined for every operating point. Then the decision tree is trained using the database obtained from the previous stage. Simulation results...
This paper describes a practical method of Online Risk Assessment (ORA) on urban power system. It includes the Online Probabilistic Risk Indices (OPRI) & their arithmetic, and the models for computing parameters varying with operating conditions which are used for Probabilistic Risk Indices calculation. The ability of the method can provide operators in control center the near term identification...
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