Influence of circuit breaker replacement on power station reliability (original) (raw)
Related papers
International Journal of Industrial Electronics, Control and Optimization (IECO), 2019
Over the recent years, a number of new maintenances methods for high voltage substations have been introduced to reduce the number of substation events. The primary purpose of the present study is to presents a Cost-benefit analysis for Circuit Breakers (CBs) in a substation equipped with Condition Monitoring (CM) devices. To this end, a mathematical formulation to categorize and model equipment failures based on their severity is developed. By CM, some of severity failures, named major failures, can be detected early, and corrected as the minor failure. This formulation quantifies the effect of CM devices on the outage rate and Predictive Maintenance (PDM) rate of the equipment. The PDM rate is used to modify the Markov maintenance model for the equipment. The proposed modified Markov model quantifies the effect of CM on the maintenance costs and lifetime of CB. The New Markov model is compared with the Preventive Maintenance (PM) model. Expected Energy Not Supply (EENS) and reliability Cost are calculated with and without CM on CBs. Finally, the proposed model is applied on the CBs of 400/132/20KV substation in the Khorasan Regional Electricity Company (KREC) in Iran. The obtained results show that CM on CBs of substations improves the EENS and reliability cost by 82.43 %. Moreover, the maintenance cost of the proposed model shows an improvement of 9.
Reliability‐centred maintenance for circuit breakers in transmission networks
IET Generation, Transmission & Distribution, 2014
Reliability of power system can be influenced by the maintenance strategy adopted for the system's equipments. This study focuses on power circuit breakers maintenance planning based on the concept of reliability-centered maintenance (RCM) and applies the proposed approach on the 400 kV transmission network in Khorasan province in Iran. The RCM strategy takes into account the technical condition and importance of each circuit breaker from the network's perspective. The technical condition index of a specific circuit breaker is a numerical representation of the physical health of the breaker and can be evaluated by some criteria. To determine this index, the performance of the circuit breakers during interval 2007-2012 is considered. The importance of each circuit breaker is related to the consequence of its failure on the network. As the main drawback of the available researches in this area is the lack of a generic tool to determine the importance of the circuit breakers, this study proposes a three-stage procedure to accurately evaluate the importance of the circuit breakers. The main idea in the proposed approach is to analyse all failure modes of the circuit breakers and simulate the effect of each failure mode on the overall expected energy not served. The obtained results show the efficiency of the proposed approach.
Substations SF6 circuit breakers: Reliability evaluation based on equipment condition
Electric Power Systems Research, 2017
This paper presents a new methodology to define a priority scale for maintenance actions in substations, based on the development of a Composite Risk Index (CRI) associated with each device. Two auxiliary indices are built: Basic Condition (BC) and Operating Condition (OC), representing the physical and functional characteristics of the equipment that can compromise their performance and contribute to the occurrence of failures. Their evaluation is helped by a Technical Capacity Index (TCI), which evaluates how much the equipment has been affected by wear and tear, in the assessment of the Basic Condition, and the classification of the equipment defects by degrees of severity, in the assessment of the Operating Condition. Two cascading Fuzzy Inference Systems of the Mandani type are used, the first in defining the BC, and the second to obtain the equipment CRI denoting maintenance priority, which may then be used in planning maintenance actions. The methodology is verified through an SF6 circuit breaker CRI assessment, and its priority scale for maintenance planning. The method for evaluating the SF6 circuit breakers reliability is validated through a comparison with a statistical approach, using real data collected from equipment installed in Eletrobras Eletronorte Transmission System, in Rondônia, Amazon region of Brazil.
IJERT-Reliability Analysis of Circuit Breakerin the Nigerian 330-kV Transmission Network
International Journal of Engineering Research and Technology (IJERT), 2014
https://www.ijert.org/reliability-analysis-of-circuit-breakerin-the-nigerian-330-kv-transmission-network https://www.ijert.org/research/reliability-analysis-of-circuit-breakerin-the-nigerian-330-kv-transmission-network-IJERTV3IS030541.pdf This paper is concerned with using the fault analysis to establish the requirements for the proper selection of circuit breaker; A Case Study of Power Holding company of Nigeria (PHCN) 330-kV Transmission Grid System. The work is modelled for Fault Analysis and it is written in a flexible MATLAB programs to accommodate addition or reduction in the Transmission Grid System. It aimed at establishing the Circuit Breaker Capacity at any point in the system. The result is then compared with the existing circuit breaker capacity of PHCN 330-kV system. The short-circuit fault is simulated by combining a solution of algebraic equations describing the changes in the network with a numerical solution of the differential equations. Two MATLAB programs were written and simulated; one for Lord Flow study to know the pre-fault bus voltages based on Gauss-Seidel Method; the other for Short Circuit Studies which made use of Thevenin's theorem application. The highest Circuit Breaker Capacity established by the result of this study is relatively lower and the investments needed for this are smaller compared with the normal practice with PHCN system. This reveals that PHCN system can be protected with this low capacity circuit breaker with a reduced cost effectiveness and equal sensitivity which is a breakthrough in terms of Circuit Breaker Capacity in the field of power system protection.
The need to improve asset management frameworks has been a major concern among industrial consumers in Uganda. Poor asset management increases frequency of faults among industrial consumers thus resulting into poor quality of power supplied. This research was developed based on the fact that cases of cascaded failures in connected systems have rampantly increased among industrial consumers in Kawempe Industrial Area. This has been due to factors such as proliferation of substandard circuit breakers, malfunctioning of circuit breaker components, external conditions that affect circuit breaker performance such as temperature, dust, etc., and negligence in conduction of compliance tests among others. These factors have not been put into consideration for the sake of effective asset management. Prior to implementation of an effective asset management framework, there is need for diagnosis of the present factors that hamper effective asset management and develop replacement strategies. This paper focused on Circuit Breakers (CBs) since they consume a large proportion of budgets of maintenance of utilities and are critical to system reliability. The parameters influencing CB performance were determined by Weibull modeling in MATLAB 2018: findings revealed that the industrial CBs had a maximum hazard rate of 5.6% with an average mean time-to-failure of 13.47 years, which represents a high propensity to death and critical condition of all CBs.
Assessing Circuit Breaker Life Cycle using Condition-based Data
How to make decisions to optimally allocate the resources by deciding when to perform maintenance on power apparatus is a critical issue, especially with present economic scenario in power industry. This paper proposes a new approach to assess the circuit breaker's life cycle or deterioration stages using its control circuit data. In this approach, the "classical" healthy, minor and major deterioration stages have been mathematically defined by setting up the limits of various performance indices. The model can be automatically updated as the new real-time condition-based data become available to assess the CB's operation performance using probability distributions. The methodology may also be used to quantify the effect of maintenance making use of the defined performance indices, which further helps in developing system-wide riskbased decision approaches for maintenance optimization. Case studies using field data recorded at different times during operations of circuit breaker are presented at the end.
Operation of Circuit Breakers: Data and Analysis
Multidisciplinary Journal for Education, Social and Technological Sciences
An attempt has been made for the analysis on Circuit breakers (CBs) this paper. First, the types and arcing phenomenon of Oil and SF6 Circuit breakers were briefly discussed. However, various CBs were analyzed in terms of certain outage frequencies and reliability indices to ascertain the most reliable CB. This was possible using data collected from the 33kV Transmission Company of Nigeria (TCN) New Haven, Enugu. After the analysis, Emene Industrial CB had the highest value of availability of 0.9999 and the lowest tripping report while Ezillo had the highest failure rate of 0.1032.
The Analysis of Failed-type and Symptom of High Voltage Circuit Breaker for Performance Assessment
The performance of high voltage equipment in electrical power system should be assessed and clearly identified as supported reasons for planning the renovation task of electrical asset. Thus, the performance assessment based on failed-type and symptom for high voltage circuit breakers rated as of 115 kV, 230 kV and 500 kV are focused in this work. The scattering failure events are systematically recorded and analyzed by using statistical techniques. Since numbers of circuit breakers from each manufacturer are different, the failure rates of every manufacturer are calculated and compared. After that the failure evaluation is performed. Then, the symptoms of failure are classified for each voltage level. The known failure rate and symptom are used as criteria for performance evaluation of those high voltage circuit breakers. The proposed criteria can also used with other high voltage equipment in the power system.
Model for quantifying the effect of circuit breaker maintenance using condition-based data
Power Tech, 2007 IEEE Lausanne, 2007
Recent trend in maintenance is to optimize the frequency of inspection and repair according to the condition of the equipment being maintained. Condition-based maintenance introduces additional investment in monitoring equipment and analyzing systems. This approach is acceptable only if the benefits are greater than the existing cost of maintenance and additional equipment/software. Low cost "circuit breaker monitors" along with signal processing modules and expert system modules are available to monitor the circuit breaker control circuit signals.