Analysis of the effect of location and failure rates of fault current limiters on substations reliability

Summary Reliability and efficiency of electric power systems (EPS) operation depend on the adequacy of information about quasi‐state and transient processes in EPS used for their research, design, and operation. A value of short‐circuit currents (SCC), especially their maximum values, is one of the important information used for different tasks. The difficulty of obtaining this information is the need to use a large‐scale EPS mathematical model for SCC calculation. The total mathematical model of any large‐scale EPS is a stiff and nonlinear system of differential equations of high order. Such system cannot be solved analytically. Satisfactory solution is also impossible by using the numerical approach that leads to the need for applying simplifications and limitations reducing the adequacy of simulation results. Therefore, each solution should be validated. The comparison of simulation results with the field data is the most reliable way of validation. However, the acceptable amount of field data cannot be obtained in the foreseeable future in view of the obvious variety of EPS modes, especially emergency ones. An alternative way of validation is suggested in the paper: the using of an adequate reference model instead of field data. The experimental sample of hybrid real‐time power system simulator having the necessary properties and capabilities is used as the reference model. The indicated possibility of SCC calculation validation is proved by the experimental studies shown in the paper.

Section: Software Tools For Semcmentioning

confidence: 98%

Section: Analysis Of the Software Tools Properties And Capabilitiesmentioning

confidence: 99%

A validation approach for short‐circuit currents calculation in large‐scale power systems

Suvorov

Gusev

Andreev

et al. 2020

“…Zhao 5 proposed a fast sampling method based on Monte Carlo sampling for grid risk assessment and system implementation; Wang 6 reported a study of risk assessment using Monte Carlo simulation for the safe operation of a large power grid; Chen 7 conducted intensive studies of risk assessment of power grid operation modes based on Monte Carlo simulation; Zhu 8 carried out a reliability evaluation of Sichuan Power Network using Monte Carlo simulation technique; Shi et al 9 proposed a power grid risk analysis method based on assuming the fault obeys normal distribution; He et al 10 evaluated the risk in urban network planning based on fuzzy theory, and the probability of the risk factors are assessed by questionnaire; Cheng et al 11 put forward a power system reliability evaluation method based on the assumption that component's fault is normal distribution; Li et al 12 raised a transmission line overload risk assessment method, and the transmission line overload fault is assumed to be normal distribution; Deng et al 13 proposed a risk assessment of power system in wind power uncertain environment, and the wind power output is assumed to be normal distribution; Wang et al 14 and He et al 15 assumed that probability distribution of transmission lines or transformer faults is approximately Weibull distribution; and it is very common that the transmission lines tripping probability or failure rate of a given unit in power system is assumed to be a fixed value in several studies. [16][17][18][19][20][21][22][23] These methods have good computational efficiency for risk assessment of a large power grid. But, they set the failure probability of grid components at a fixed value or an assumed distribution without analyzing the contribution of each component to the grid risk.…”

Section: Introductionmentioning

confidence: 99%

Research and application of efficient risk analysis method for electric power grid multiple faults under widespread wildfire disasters

Guo

Zhou

et al. 2019

Summary In recent years, wildfire disasters have occurred frequently in China, with currently more than 70 000 wildfires annually. During the high wildfire disaster period, multiple transmission lines readily trip simultaneously. This poses a serious threat to the safe operation of a large power grid. The probability that multiple transmission lines will trip is far greater than for only a single transmission line. The degree of risk to the power grid needs to be analyzed under multiple tripping combinations of transmission lines caused by wildfire disasters. However, when a large number of wildfire points is involved, the number of such transmission lines tripping combinations become huge, and rapid analysis of the risk to the power grid in these conditions is very difficult. In the present study, the probability distribution characteristics of power grid fault under wildfire disaster were analyzed using historical data on transmission line wildfires and wildfire tripping. A Markov chain Monte Carlo sampling method is proposed to match the probability distribution characteristics of transmission lines tripping under wildfire disasters. The precision of multi‐fault combination sampling is improved effectively. A quantitative power grid risk analysis method is put forward to estimate the sort of transmission lines risk under wildfire disasters efficiently. This gives scientifically based guidelines for reducing the risk to a power grid from widespread wildfire.

“…As above, it is expected that FCL is widely used in the power system in the future. However, it is necessary to consider all facets associated with the installation of FCL in the power system . One of the aspects is the impact of FCL installation on the distance relay performance.…”

Section: Introductionmentioning

confidence: 99%

“…However, it is necessary to consider all facets associated with the installation of FCL in the power system. [8][9][10][11] One of the aspects is the impact of FCL installation on the distance relay performance. Conventional distance relay effectively detects the occurrence of the faults in a transmission line with the help of six impedance measurement units.…”

mentioning

confidence: 99%

Investigation of the performance of distance relay in the presence of saturated iron core SFCL and diode bridge type SFCL

Barzegar-Bafrooei

Foroud

2018

Summary Owing to the advance in the development of fault current limiters (FCLs) for high voltage, there is the possibility of using this equipment in transmission systems in the future. However, distance relay that is used to protect the transmission line against shunt faults, is subjected to the more direct impact of FCL installation. In this paper, the effect of the saturated iron core superconducting FCL (SFCL) and three‐phase diode bridge type SFCL on the apparent impedance seen by the distance relay, and its trip boundaries are extensively investigated. To perform the evaluations, the impact of SFCL on the measured impedance by the ground and phase distance relays is investigated through the analytical analysis. For evaluations, two possible locations for installation of SFCL including before and after voltage transformer are considered. Finally, both SFCLs are modeled in the PSCAD/EMTDC software, and the effect of each type on distance relay performance is investigated. Fault type, fault location, and fault resistance are the parameters which are considered in the simulation studies. The obtained results show the adverse impacts of both types of SFCL on distance relay performance; however, the impacts of each type are different from another. In this regard, in order to enhance the sensitivity and the security of the relay in this circumstance, the remedial action is proposed.