ECN publication
CRISP - Fault detection, analysis and diagnostics in high-DG distribution systems
Andrieu, C.; Fontela, Miguel; Raison, B.; Penkov, D.; Bacha, S.; Hadsjsaid, N.
Published by: Publication date:
ECN Energy in the Built Environment 14-9-2007
ECN report number: Document type:
ECN-O--07-011 Other
Number of pages: Full text:
38 Download PDF  

The fault in the electro technical meaning is defined in the document. The main part of faults in overhead lines are non permanent faults, what entails the network operator to maintain the existing techniques to clear as fast as possible these faults. When a permanent fault occurs the operator has to detect and to limit the risks as soon as possible. Different axes are followed: limitation of the fault current, clearing the faulted feeder, locating the fault by test and try under possible fault condition. So the fault detection, fault clearing and fault localization are important functions of an EPS to allow secure and safe operation of the system. The function may be improved by means of a better use of ICT components in the future sharing conveniently the intelligence needed near the distributed devices and a defined centralized intelligence. This improvement becomes necessary in distribution EPS with a high introduction of DR. The transmission and sub-transmission protection systems are already installed in order to manage power flow in all directions, so the DR issue is less critical for this part of the power system in term of fault clearing and diagnosis. Nevertheless the massive introduction of RES involves another constraints to the transmission system which are the bottlenecks caused by important local and fast installed production as wind power plants. Dealing with the distribution power system, and facing a permanent fault, two main actions must be achieved: identify the faulted elementary EPS area quickly and allow the field crew to locate and to repair the fault as soon as possible. The introduction of DR in distribution EPS involves some changes in fault location methods or equipment. The different existing neutral grounding systems make it difficult the achievement of a general method relevant for any distribution EPS in Europe. Some solutions are studied in the CRISP project in order to improve the current state of fault diagnosis (investigation time and solution cost involved with a dedicated use of ICT) and make this power system function adequate with the future high DR situation expected. The approach followed to improve the fault diagnosis inside the MV distribution involves new consideration and understanding about the control of MV cells. The document describes the concept of MV level one cell, which is important for the future fault location tools. This level one cell groups all the possible configurations of linked feeders by emergency EPS switches. This concept will be used in the future as a logical and topological reference cell for different functions: load flow, DSM, disconnecting protection. The improved flexibility and coordination between feeders, as proposed in the HTFD application, will have links with the other expected functions needed to make the distribution EPS more autonomous or intelligent.

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