EXPERIENCE AND STRATEGIES FOR REFURBISHMENT OF PROTECTION AND CONTROL SYSTEMS IN JAPAN

摘要

This paper reports experience and strategies forrefurbishment of protection and control systems in theelectric power companies of Japan. Additionally, itdescribes the prospect of the technology with regards tothese systems. They are based on the survey andresearch conducted jointly by the electric powercompanies. The survey and research includes the surveyof the current state of operation and refurbishment ofexisting equipment, the life diagnosis by acceleratedtesting and the survey of productremodeling/superseding of manufacture.As the indicator for use in judgment to refurbishanalog-type protection equipment, the authors studiedthe requirement by the power system changing, thefailure statistic and the componentremodeling/discontinuation based on from 20 to 25years. A proposal was presented for methods torationally make decisions on refurbishing analog typeprotective equipment according to scores based on theseassessment indicators. This method is applied as a guidefor replacement, in case the assessment items areweighted differently in some electric power companiesaccording to its policy. An example to make cleardeteriorated equipment parts and the deteriorationphenomenon is showed to carry out a life diagnosis testusing removed protection equipment in order to increasethe precision of these judgment indicators for the future.The control system is analyzed with three-part,remote terminal unit, a control system in a controlcenter and a control system in substation. The recentcontrol system applies the general communicationprotocol and the numerical type by analyzing thecommunication protocol and type. Regarding controlequipment, electric power companies tend to placepriority on such reasons for replacement as increasedfunctionality based on the latest communicationtechnology and numerical technology and general costcutting through system integration and replacement,rather than the concepts of replacement based onassessment indicators for protective equipment fromtrend and surveys. As a result, the average system usageis almost 20 years. Additionally, as new control systems,we introduce the substation control system using LANand a remote control system apply the new factors byintegrating and removing the present system.Finally, we describe the prospect of this equipmentand systems. Cost reduction is progressed by selectingsuitable refurbishment time for the protection andcontrol system and integrating the control system. Weexpect that the equipment and systems will bedeveloped to apply information-communicationtechnology to reduce cost as follows.1. increasing the use of general-purpose LANs for localuse of substations based on an international standardprotocol2. increasing the efficiency of communication channelsby means of the internet and intranets3. increasing the remote operation and monitoringfunction by Agent technology.