Section 15 Commissioning and maintenance of the
fault clearing system
About this chapter
This chapter discusses maintenance tests and other periodic maintenance measures.
15.1
Installation and commissioning
The protection IED is in an on-guard situation where the IED can be inactive for
several years and then suddenly be required to operate within fractions of a second.
This means that maintenance testing with certain time intervals should be
performed to detect failures of the protection IED or the surrounding circuits. This
is a complement to the advanced self supervision in the modern protection IED.
IEDs are not expected to deteriorate with usage but extreme conditions, such as
mechanical shocks, AC or DC transients, high ambient temperatures, and high air
humidity always have a certain likelihood of causing damages.
Delivered equipment undergoes extensive testing and quality control in the ABB
manufacturing program. All types of IEDs and their integral components have been
subject to extensive laboratory testing during the development and design work.
Prior to series production of a specific IED, it is type tested according to national
and international standards. Each individual IED in normal production is
individually tested and calibrated before delivery.
Protection IEDs installed in an apparatus cubicle shall be checked in various ways
before delivery. Insulation test (to check for bad wiring) and complete testing of all
equipment with injection of currents and voltages is performed.
During the design of the station, certain steps shall be taken to limit the risk of
failures, for example, all IED coils are connected to negative potential to earth to
prevent contact corrosion due to electrolyte.
Certain circuits are continuously supervised to improve their availability. Examples
of such supervisions are:
• Trip circuit supervision
• Protection DC supply supervision
• DC system earth fault supervision
• Busbar protection CT-circuit supervision
1MRK 504 088-UEN C Section 15
Commissioning and maintenance of the fault clearing system
213
Installation and commissioning manual
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