Fault Indicators of Partial Discharges in Medium-Voltage Systems

Stefan Hamacek,Stanislav Misak

doi:10.15598/aeee.v11i4.910

Abstract

The safety and reliability of the electricity system, these are the two basic keywords present in the energy sector. One of the ways to improve the overall security of the electricity system is to reduce the failure rate of transmission lines. In medium-voltage distribution systems, this predominantly concerns overhead lines and cable lines. This paper discusses options on how to decrease the failure rate of medium-voltage overhead lines with covered conductors.

Highlights

Covered conductors are able to withstand mechanical and electrical stress caused by falling trees or branches
Along with the development of covered conductors, and based on long-term experience in Nordic countries, the system with covered conductors used in medium voltage (MV) lines is used in the Czech Republic
Construction of an overhead line with suspended covered conductors is not very different from lines using bare conductors; the most important advantage is that the covered conductors allow a shortening of the distance between phases of roughly one-third compared to the phase distance which is usual for bare conductors

Summary

Introduction

Trees fallen on the lines can be removed later when conditions are more favourable. It is possible to use the above methodology, which is protected by national and European patents, and detect different types of faults such as fall of conductors to the ground, contact of a tree branch with a conductor or fall of a tree branch; at present, it is not possible to determine the specific fault type. For medium-voltage distribution operators, this represents very important information, since each of the above faults has a different time development, and it may be removed in different time horizons This can be helpful for mediumvoltage distribution operators for optimum planning of the schedule for defect removal, and it can thereby increase the overall safety and reliability of the system [4], [5], [6]. A more detailed description will be presented in the following chapters

Analysis of Partial Discharge Activity

Coupling Rupture and Fall of CC onto the Mast Monsole

CC Coupling Rupture and Fall of CC to the Ground

CC Coupling Rupture and Fall of CC onto a Water Surface

Description of the Developed Software

Conclusion