Locating ground connections based on detecting changes in the reverse part of voltage
The quality and reliability of the electricity supply is greatly affected by breakdowns in electrical power networks, which must be promptly located and removed as soon as possible. In the case of single-pole breakdowns (connection of one phase and the ground) in ineffectively earthed systems, a ground connection occurs. This breakdown is extremely difficult to localize, which means it takes longer to remedy. We are offering a device which can quickly and precisely find this connection.
Description of the technology
Current methods of detecting ground connections do not represent an optimum solution for widespread use. The reason is that detection using current methods causes excessive interruption in the electricity supply in the distribution network due to inaccurate localization, or the localization of the breakdown may not be possible due to the complexity of high-voltage distribution networks.
Our new device eliminates the drawbacks of the current options of ground connection detection. The invention is based on a method for quickly and accurately finding the point of breakdown inside a distribution network, in particular in compensated networks where localization of a breakdown is most difficult. This comprehensive method enables the point of ground connection or asymmetrical short circuit to be localized inside a high-voltage distribution network which is operated as isolated, ineffectively or directly earthed. The new method uses recorded changes in the reverse parts of voltage and current, caused by asymmetry as a result of the breakdown, to localize the breakdown. Single changes to the reverse parts of voltage are monitored on the low voltage side of all or selected distribution transformers of the relevant system, and the reverse part of current is monitored at the point of the supply transformer, or in the single outputs of the feeding distribution station.
Autor: Pastorius 2011 Wikimedia Commons
Main advantages
Precise determination of the points of asymmetrical breakdown inside extensive distribution systems
Saves time
Option for multiple localization of ground connection to increase precision
No need to detect affected output with ground protection
To determine the point of breakdown the method uses impedances which are already well known
Precision of the breakdown localization corresponds to the number of used voltage monitors – high variability according to the acceptable level investment and operational costs
Localization of breakdown is also possible in the event that several voltage monitors fail
The device can be also used for locating sources of pronounced non-symmetry in a distribution system
Voltage monitors used by the device can be also used for other purposes, such as measuring the characteristic values of voltage in low-voltage systems
