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Installing subsection switches on distribution network feeders is an effective measure to improve system reliability. In this paper, based on value engineering, a new method is presented to determine optimal subsection scheme. By application of value engineering theory, a new objective function is constructed. The new objective function, based on cost-benefit analysis, is constructed by reference...
The introduction of sustainable and renewable energy sources into traditional networks will be limited if we continue to use inappropriate methods for security analysis. The probabilistic nature of variable and non-schedulable renewable generation is not well represented in current on-line security assessment schemes. This paper presents a novel method of analyzing and comparing system security schemes...
A new reliability index is defined considering correct inaction, failure events and the failure probability of protected component in protective relays according to the risk theory. Relaying reliability is separated into the two different aspects of dependability and security in the calculation based on the losses resulted from failure events. A general 8-state Markov model is set up where resist-operation...
In this paper, a new method based on equivalent network composed of zone-networks (zone-elements) is proposed and applied to reliability evaluation of distribution systems with the switch fault. In the method, the one-line diagram of the system is partitioned into zones with the auto (or non-auto) switch being the boundary; then two equivalent networks are respectively formed by two types of zone-elements...
The reliability of electricity supply is required by users increasingly, and whether to invest the reliability and voltage quality has been a point of contention. Thus, the assessment of voltage sag becomes acute. In this paper, the acceptable indices considering system performance and user characteristics are proposed for comprehensive assessment of voltage sag, including the reliability of the system...
In order to make up for the deficiencies of centralized power production and distant transmission, microgrid becomes a hot topic of research in distributed energy systems in recent years, along with the increasing distributed generation systems, the improvement of information technologies, the development of the power market and the shock of serious blackouts. And they will play an important role...
The calculation of penetration limits of wind farm is an important issue on the planning of wind farm, Basing on reliability modeling of wind farm, this paper proposes a method to calculate penetration limits of wind farm by taking reliability index as restriction. Since load demand and output of wind farm are of randomicity, and the restriction is expressed as form of reliability, Monte Carlo method...
The integration of a large number of wind farms will have a significant impact on the reliability performance of the electric generation and transmission systems. In this paper, an adequacy evaluation model of wind power integration in power system based on the sequential Monte-Carlo simulation approach is presented. This model is applied to simulate power system including wind power generation. Depth...
Based on the conventional Monte-Carlo simulation algorithm, this paper considers the primary elements connection in the substation. By means of topology analysis algorithm, the substation elements connection analysis is completed first and the logical nodes and the connectivity between logical nodes and lines are determined. Then, the equal calculating model for network is presented. Meanwhile, after...
Power grid is the bridge between power plants and loads. It has direct influence to the security, reliability and economic efficiency of power system operation. With the power grid continuous expanding, it becomes more and more difficult to understand and analyze this influence clearly. According to mentioned above, this paper proposes a new index named power grid transmission performance index (PI)...
The deployment of IEC 61850 process bus in substations calls for an impact evaluation of possible process bus architecture scenarios on the performance of numerical protection systems. Six alternative system architectures are proposed based on a component redundancy perspective. The functionality of each system is assessed using reliability block diagrams based on a success-oriented network. System...
Microgrids have been considered as important parts of future power systems, which are believed to be capable of solving some tough problems in large systems. In emergency, a microgrid is often required to reconfigure itself as soon as possible in order to support continuous electricity to essential loads. Types of operations, including topology switching, load shedding and generation regulation, are...
With the prevalence of distributed generation (DG) and development of microgrid, tremendous opportunities and challenges are presented. The penetration of microgrids modifies the energy convection in traditional power systems, which has a great impact on the stability of existing systems. In this paper, the influence of the penetration ratio of microgrids on voltage variety and power angle stability...
Because of the great stochastic of wind power, it is difficult to forecast it accurately and the forecasting result can not be applied to unit commitment directly. A dispersed probability distribution model is built based on statistics of wind power forecasting error, the cumulated outage capacity table of the units is combined with this model and fitted by Gaussian function. Unit commitment risk...
Modern power systems require that power delivery components operating at very high voltages use the minimum amount of insulation necessary for reliable operation in view of economic considerations. The insulation is subject to a high electrical stress, so that partial discharge (PD) activity may initiate under normal working conditions in high voltage equipment that is aging or has flawed insulation,...
The paper proposes the protection schemes for closed loop distribution network with distributed generators. Generally, Most of distribution networks are operated in radial or open loop due to the security and protection limited. With the rapid expansion of modern power systems and demand for high quality of power supply, the closed loop operation is adopted gradually. Furthermore, with the increasing...
Combined with risk indices of comprehensive reliability assessment and economic assessment theory, there may be trade-off between system installations cost and power interruption cost in the competitive power market environment. To coordinate reliability and economy, this paper proposed an overall framework of optimal reliability algorithm for bulk power system based on total owning cost (TOC). Interruption...
At present power company challenge is how to quickly and effectually implement outage management, the upgrade of both metering technology and communication system makes the development of automated meter reading (AMR) systems possible. Signals from automated meters can provide extra information for outage detection and decision processing as well as restoration phases of outage management. In this...
This paper introduces a kind of method for quickly calculating line current under emergency state. The safety margin index of line current is introduced. The index is used to identify the key lines affected by the tripping line and forecast the system multiple fault event. Based on above all, the reliability evaluation algorithm using state pruning based on margin of safety is proposed. The margin...
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