The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
With the aim to solve the frequent network reconfiguration problem caused by link failure in the broadband powerline communication (BPLC) system, this paper inroduces the two-way power frequency automatic communication system (TWACS) into current BPLC system. And in this BPLC and TWACS integrated communication system, a TWACS signaling based routing searching algorithm is proposed, to meet the requirements...
Due to the increasing low capacity distributed generators (DGs) installations and penalization of supply disruptions in electrical distribution grid, it is necessary to invest in the distribution protection system. This paper discusses profitability of installation of relays with distance protection function that could protect lines of different voltage levels, lengths and other relevant attributes...
The relay protection and automation (RPA) is the essential part of the power system, which ensures the system failure-free operation. However, the inadequate attention is paid to the RPA operability problem during the electrical network reliability assessment. The study is focused on the determination of the RPA states probabilities with consideration of many factors characterizing the RPA ability...
This paper is a summary of a case study of a pulp and paper mill that had greater than 100 solidly grounded substations. In order to reduce the likelihood of an arc flash, they were changes to a high resistance grounded system. This change increased the safety and reliability of the facility as well as reduce arc flash incidences in the low-voltage substations.
This paper describes an analysis on power system breakdown sequences caused by circuit breaker and protective relay failures, and applies this to plan a probabilistic test and maintenance schedule for these periodically tested components. The paper shows that a probabilistic and component importance based test and maintenance scheduling can minimize the system breakdown frequency caused by the component...
The sharing of information, such as the root cause of misoperations and the lessons learned from those events, has long been a valuable part of the overall efforts of the power industry to improve the reliability of electric power. However, the fear of audits, noncompliance fines, competitive disadvantage, and lawsuits has injured our ability to discuss, teach, and learn. We share a responsibility...
This paper describes how a switchgear modernization project in a major petrochemical and refining process opened the door to new methods of integration between substation protection and process safety automation. It explores how a risk mitigation project's need for a Safety Instrumented Function (SIF) to detect a refinery wide power outage used the technology the modernization project provided without...
With the advent of IEC61850 standardization, increasingly more power utilities adopt a standardized environment with modern Intelligent Electronic Devices (IEDs) in their substations. As a consequence, conventional test procedures face a future of uncertainty, and established testing routines are called into question. The functionalities and new protection system arrangements of IEDs cause changes...
The computer based interlocking system equipment of station is very important which does matter with the rail operation safety. TYJL-ADX computer based interlocking system has a structure of 2×2 totally which is a safe redundancy. The FCX unit of one's mainly logic architecture and FFC unit of operation expression have two systems which can be used as master/slave each other. The each system has a...
This paper is a case study of the design process and validation of a simple and effective solution to satisfy the North American Electric Reliability Corporation (NERC) PRC-005 protection system maintenance program (PSMP) requirements. The example solution is a protection system monitoring (PSM) application for an in-service system at a hydroelectric generating station. This PSM system uses simple...
Protection systems have evolved from assemblies of electromechanical single function devices, through multiple generations of analog solid state designs, to advanced microprocessor based protection systems. The newest generations of microprocessor relays can perform a myriad of applications and functions in one physical unit. The skills of the engineers and technicians who manage these protection...
Protection device is repairable system, and its routine maintenance is Minimum Maintenance. With the number of maintenance increasing, both the reliability of relay and the economy of maintenance are decreasing. Therefore, it should be replaced at a proper time. The optimal replacement strategy was studied based on relay reliability and maintenance economy according to field data. It first constructed...
This paper reviews past and present NERC/FERC requirements for relay testing of grid connected protection systems in the US/Canada with a focus on the final draft of PRC-005–2. It will attempt to clarify core requirements that are changing past testing philosophies and address practical testing methods for legacy relays and newer multifunctional digital relays. During the past decade, protective relays...
Protection system in a power system domain plays a vital role as watchmen to safe guard power system apparatus in the event of faults. The integrity and effectiveness of these watchmen is heavily dependent on the reliability of the components that makes up the system. One of the main components in a protection system is protective relays that provides decision making element for correct protection...
The basic concept of redundancy is simple. Instead of relying on a single piece of equipment, there are duplicate or triplicate sets that perform the same function. Consequently, if one piece of equipment fails, the function will still be performed by a redundant device. Redundancy of components plays a major role in elevating the reliability of protection systems. The impact on the power system when...
The NERC Protection System Maintenance and Testing Standard Drafting Team has, in recent months, issued its draft of Reliability Standard PRC-005-2, Protection System Maintenance, along with supporting explanatory documents. The new Standard implements FERC-ordered changes by adding specific requirements for maximum maintenance time intervals and activities. However, the new draft Standard also opens...
In order to enhance both dependability and security which are two aspects of relaying system, self-checking and monitoring facilities are usually considered along with routine test. In practice, back-up relay can has mal trip when not required and may fail to trip when required which may cause power system blackout due to cascading failure. Generally, this situation is not taken into account in the...
This paper provides real-world examples of the benefits to industrial systems when aging and obsolete electromechanical relays are replaced with modern, microprocessor-based relays. Microprocessor-based relays eliminate failure and degradation of operations due to moving parts. They also reduce or eliminate the time to detect a failure via internal self-test diagnostics and monitoring, information...
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...
The paper describes the principles regarding periodical testing of protection relays in the Finnish national grid. Three internal utility studies aiming at prolonged test intervals are presented. The first is an analytical study for modernisation of relay testing procedures, the second is a reliability centered maintenance (RCM) analysis for protection and, finally, the third is a fault and risk analysis...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.