Apostolov, Alexander
Areva Automation
The economic pressure of today’s world of deregulation is forcing many utilities to change from “scheduled” maintenance to “preventive” or “event driven” maintenance.
One approach to achieving this goal is by installing specialized monitoring devices that will analyze the performance and operation of the substation equipment and indicate the need for preventive maintenance. However, this requires the installation of another type of device, its design, commissioning and maintenance. And in many cases these costs may limit the implementation of such devices in the substation.
Multifunctional IEDs that are being installed in the substation to perform protection, control and monitoring functions are loaded with numerous functions that can be used successfully to provide a sufficient level of preventive maintenance related information.
Multifunctional protection IEDs include all or at least a subset of the following functions that can be used for preventive maintenance:
. Breaker maintenance: auxiliary contacts status, number of operations, number of fault trips, interrupted current, breaker operating time, trip circuit supervision
• Voltage Transformers or circuit maintenance: single or two phase voltage transformer or voltage circuit failure, three phase voltage failure, closing the line without voltages available
• Current Transformers or circuit maintenance: single or two phase current transformers or current circuit failure
• Detection of broken conductor condition in the protected circuit
• Trip circuit failure detection
All of the above listed functions and how they are implemented in state-of-the-art IEDs are described in the paper.
