VERFAHREN ZUR MASSESCHLUSSERFASSUNG, -LOKALISIERUNG UND -WIDERSTANDSBESTIMMUNG BEI EINEM ERDFREIEN UMRICHTERSYSTEM

• Main Authors: KIRCHLER ERWIN, SCHAMBOECK HANS
• Format: Patent
• Language: German
• Published: 15.11.1999
• Edition: 6
• Subjects: CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; GENERATION

A method for earth-short detection, location and resistance determination in an unearthed converter system, comprising at least two unearthed converter elements having a voltage intermediate circuit and an earth-short detection device, which has an intermediate- circuit centre point which is earthed through a high impedance and by means of which the low-frequency element of a measurement voltage, caused by dissipation currents, is detected. In this method, the dissipation current is detected on- line and, if an alternating component of the low- frequency element of the dissipation current is detected and this frequency corresponds to the frequency of the applied third harmonic of the motor voltage, an earth short is located in the motor area or in the area of the motor converter output, and the earth-short resistance Rx is determined with the aid of a convolution integral and, if a DC component of the low-frequency element of the dissipation current is detected, an earth short is located in the intermediate circuit, and if the DC component falls when the brake controller is pulsed, an earth short is located at the root of the brake controller, and the earth-short resistance Rx is calculated using Ohm's Law. This solution allows earth-short detection to be carried out easily and reliably in a wide range of equipment.