Reliability in the supply of electrical power begins with the avoidance of interferences on the grid. Cables and overhead lines must therefore be checked at regular intervals. This ensures that the equipment is working properly. Also, measurements on cables and overhead lines are required to determine parameters which are needed elsewhere. Thus, positive sequence and zero sequence impedance of transmission lines play a central role in distance protection and fault locations. OMICRON’s innovative testing systems support efficient, reliable, and likewise, high-precision testing of cables and overhead lines.
Partial Discharge (PD) measurements on cables and power cable systems
Partial discharge (PD) phenomena are localized dielectric breakdowns of a small portion of a solid or liquid electric insulation that is subjected to high voltage stress. As PD often precedes an insulation breakdown which can result in cost-intensive repairs, and possibly prolonged outages. The measurement of PD is a major criterion for the quality of cable and accessories and its on-site assembling respectively. OMICRON'S MPD 600 incorporates a range of leading-edge technologies in order to provide accurate, reliable and reproducible PD measurements – even under the most demanding circumstances.
Line impedance of power cables and transmission lines
Line parameters, such as positive sequence impedance, zero sequence impedance or k-factors, are important parameters of a line. These are required, for example, for the correct setting of a distance protection relay or fault location. OMICRON’s CPC 100 + CP CU1 measuring system makes it possible to measure line impedance quickly and completely, so as to determine the named values in less than 30 minutes.
Measurement of mutual coupling
For the correct setting of distance relays of twin systems the exact values of the coupling factor are required. With the multifunctional CPC 100 primary testing system and the CP CU1 coupling unit, OMICRON has developed a unique system for complete coupling impedance measurement.
Coupling of power lines into signal cables
Due to the magnetic fields around transmission lines and power cables, the effect of magnetic coupling into adjacent electrical systems is a common phenomenon. OMICRON's test system CPC 100 + CP CU1 + CP AL1 allows for accurately measuring the coupling impedance to clarify e.g. how a specific power line couples into a specific signal cable.
