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History of P&C Systems

History and Experiences

Significant product developments up to 2005 are listed below.

History and Experiences List
2005 Fully numerical line differential protection for communication either by pilot wire or direct fibre optic link (GRL150)
2004 Distance relay (GRZ100) with IEC61850, a prototype demonstrated at CIGRE in Paris
2003 Distance relay (GRZ100) with integrated communication
2002 Distribution system protection (GRD100 series)
2001 World's first commercial GPS synchronised line differential relay (GRL100) installed on 400kV network in the UK.
2000 Network solution equipment for the system monitoring and measurement
1999 Compact & high performance numerical relay (GR-series) Substation automation system (GSC1000)
1993 Toshiba's third generation numerical relay (D3)
1989 World's first microprocessor-based substation automation system applied to 275kV substation
1986 Toshiba's second generation numerical relay (D2)Since then, numerical relays have been developed to satisfy all types of application.
1985 Microprocessor-based transformer protection relay
1984 World's first microprocessor-based power system stabilizing relay applied to TEPCO's metropolitan underground cable network
1980 World's first microprocessor-based PCM current differential relay applied to 275kV line (D1)World's first microprocessor-based distance relay applied to 66kV line
1977 World's first FM current differential relay applied to 275kV line
1969 World's first static phase comparison relay having automatic testing and self diagnosis
1968 World's first preventive fault extension protection system
1960 Multi phase autoreclosing with segregated phase comparison relay applied to 275kV
1959 Static busbar protection relay
1956 Phase comparison relay applied to 275kV line
1954 Transformer protection relay based on percentage current differential
1952 Pilot wire relay applied to 275kV line
1951 Directional comparison relay
1950 Distance relay
1939 Induction cup type directional relay
1920 Induction disk type overcurrent relay
1907 Plunger type overcurrent relay