Timely solution to fault management problems

21 January 1999



Computerised Distribution Management Systems (DMS) are being widely used to manage electrical networks, but dealing with faults still stretches operators. A CEC-funded consortium has therefore developed a fault diagnosis and management system which runs alongside and in addition to the traditional DMS. It uses the same network definition and alarm/event data to provide help during abnormal conditions and recommends remedial actions.


The deregulation of the UK electricity market has made customer service the priority of every regional electricity company (REC); at the same time shareholders require year-on-year increases in profit against an average 40 per cent downsizing in staff over five years and the regulator needs to be satisfied that the REC is following best practice. This triple requirement of reduced prices to consumers, increased profit for shareholders and improved service, is a very challenging one.

RECs have to manage customer satisfaction by driving down interruptions, maintaining the quality of supply, and efficiently handling customer queries. One key measurement criterion is customer minutes lost. Reducing customer minutes lost demands major investment in distribution and network management, telemetry and engineering systems to see and understand events affecting the distribution network.

DMS packages

Distribution Management System (DMS) packages have been widely deployed in the UK to improve network security and reduce customer minutes lost. One such solution is Syseca's Network Information Management System (NIMS) package – a product which is deployed by a number of utilities, including ScottishPower, Manweb, NORWEB, MEB and East Midlands Electricity.

NIMS is fed data collected by Remote Telemetry Units (RTUs) at individual substations and other points on the network, building a real-time overview of activity on the network. This is displayed via a graphical user interface, which can be deployed on a range of workstations to highlight the actual state of the network, such as feeder zones and dead zones, while also giving fast access to plant and circuit records.

The system enables operators to quickly identify circuits which remain in service following an outage, and to ascertain the magnitude and direction of power flow through the remaining network. Automated systems such as this give greater flexibility of network assets, and greater control security, to the distribution companies.

However, even with modern distribution management systems, managing the network under abnormal conditions is a complex task, and diagnosing and responding to failures from the control room stretches operators to the limit. During abnormal operating conditions, network sensors produce a great deal of raw data which is difficult for even experienced operators to process and interpret. Therefore typically only a subset of information is registered by the operator, such as circuit breaker states, and key information relating to timing is ignored, resulting in sub-optimal or even incorrect decisions being taken. Under these conditions, managing and restoring the network hangs on three key tasks:

  • Detecting the abnormal condition;
  • Identifying the cause or causes;
  • Determining the remedial action.

    The Timely solution

    Traditionally, handling abnormal conditions in real time is done using the skill of an operator. However, the time that it takes an operator to be able to respond will depend upon the complexity of the incident and the number of messages that need interpretation. These tasks have to be integrated and automated in order to minimise the effects of outages, reduce disruption and enable smooth and secure network correction.

    One approach to achieving this is that taken by the European Timely Project consortium, which is funded by the Commission of European Communities, and led by Syseca Ltd (UK), in conjunction with ENEL SpA (Italy), CISE SpA (Italy), Heriot-Watt University (UK), Statnett SF (Norway), and the Public Power Corporation (Greece).

    The Timely Project has developed a fault management system for real-time diagnosis, location and remedial advice in the event of faults on telemetered transmission and distribution networks. This is an addition to the traditional DMS and uses the same network definition data and alarm/event data. Using component information the system analyses the fault and gives probable causes and advice on how to deal with the problem. The system, which can also be used for post-disturbance offline analysis of protection device behaviour under fault conditions, is called PowerDA. It has two components:

  • PowerDA On-Line provides real-time, on-line diagnosis of faults in high voltage electrical networks. This supplies control room staff with a major incident handling system, reducing the outage time experienced by the network.
  • PowerDA Off-Line provides off-line condition monitoring for failure prediction, allowing a utility to operate a pro-active maintenance policy.

    PowerDA uses a realistic model of the network, built using a Component Based Language (CBL) that defines the network components to be diagnosed. The accuracy of the model enables the system to react correctly to infrequent and unpredictable operational situations. PowerDA alerts control room staff to component and line-based faults, identifies the causes, and allows them to determine and implement effective strategies for remedying faults. Following a network event, PowerDA filters the mass of information presented to operators, identifies the probable underlying issue, thus enabling them to focus on the root causes of the problem, enabling remedial action to be undertaken with the minimum of delay.

    Responding quickly and accurately results in cost benefits, by reducing outage time, reducing the probability of equipment damage, and avoiding the danger of a system collapse.



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