Introduction to the History of Selective Protection

Author: Walter Schossig, Germany

Practical Tests

Often when there were savings in primary equipment additional funds were made available for more elaborate protection solutions. These solutions were tested using stage faults. There were no grids with isolated or with high resistance grounding on the 30kV grid in Berlin but Kuhlmann obtained the first measurements in 1908 having received special permission to conduct the necessary tests from the director Wilkens.



Figure 10 Testing Devices Dr. Paul Meyer AG 1925

Examples of stage faults include those in 1925 on the 110-kV-grid of the Bavarian utility "Bayernwerke"; in the 1990's on the 380-kV-grid of Switzerland/ Austria; and in the 750kV interconnection between Hungary and Ukraine.


Figure 11 Short-Circuit Stage Fault 380 kV Station Pradella

One of the first cases of a stage fault in the United States and Canada was on the high voltage terminal of transformers in 1924. Stage faults were frequently used in the 1950s in the former Soviet Union on the 30-kV, 110-kV and 220-kV systems. Shorting circuits with spring energy storage were manufactured in Poland and had an operating time of 120 ms on the 110 kV system and 200 ms on the 220 kV system. Shorting circuits with explosive cartridges were manufactured in the former Czechoslovakia and were used in the former German Democratic Republic (GDR) for testing on 110-kV transformers.



Figure 12: 110-kV Short Circuit, ČSSR (IfE).

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BeijingSifang June 2016