Protection History

Authors: Walter Schossig, Germany, and Thomas Schossig, OMICRON electronics GmbH, Austria

Testing Devices in the 1990s (Part 2)

by Walter Schossig, Germany, and Thomas Schossig, OMICRON electronics GmbH, Austria

In the last issue we covered the first devices released in the 1990s. There is a lot of material available. So, let's continue. 

The company ZERA is well established in 1994. There are several testing devices for relays available at this time. They could be used for testing an overcurrent relay, over- and undervoltage protection. Also, differential protection could be tested with Secondary Current Injection Set UBA7721 (Figure 1). To test differential protection three devices could be used, operated via integrated control. (Table 1).
To test also several relays including directional relays the test equipment RP7440 was presented in the same year (Figure 2, Table 2). This was for single phase testing.
1994 was also the year, where the control via computer was presented at Hanover Fair by ZERA. The device was called RTU, the German name was "Rechnergesteuerte Prüfeinrichtung" (RTU1).  The solution with software is shown in Figure 3. The main characteristics:

  • Fully electronic generation of test parameters
  • 3-phase voltage system (130 V)
  • 3-phase current system (20 A)
  • Frequency range: 40-130 Hz
  • Control via PC
  • Automatic test protocol storage
  • Programmable test procedure
  • Graphic display characteristics

This device was a further development of RP86. A new hardware concept was released. All amplifier and other components have been pluggable. This increased reliability and ease of servicing. All technical data have been according to the definitions of Germany's national working group at VDEW "future protection".
The software came from ZERA, the hardware was made by Spitzenberger + Spies.
Software system features:

  • Powerful test language
  • Integrated standard tests
  • Mouse operated
  • Context sensitive help
Relion advanced protection & control.
Let?s start with organization in protection testing