GE Digital Energy 735, Instruction Manual

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1–2 735/737 FEEDER PROTECTION RELAY – INSTRUCTION MANUAL
CHAPTER 1: INTRODUCTION
Current bargraph : 10 to 100%
Other
• Conventional 1 A or 5 A CT input
• Drawout case
• AC or DC control power
• Seal provision for tamper proof settings
• Output contacts:
• Trip
• Aux Trip
• Service Required
•
(737 only) pickup, trip, cause of trip outputs;
• 50A, 50B, 50C, 50N
• 51A, 51B, 51C, 51N
• RS485 communications: settings, currents, status
• 86 lockout
• Programmable block instantaneous on autoreclose.
• Ground Fault trip programmable to Aux. Trip relay, separate from Main trip.
1.1.2 Product Description
The 735/737 is a microprocessor based relay used to perform primary circuit protection on
distribution networks at any voltage level. Instantaneous and time overcurrent phase and
ground protection features replace the equivalent of 8 separate protection devices. Each
protection element can be selectively enabled by front panel dial settings. Flexible settings
and selectable curve shapes enable accurate coordination with other devices. Cause of
trip indications and a bar graph load monitor are provided on the front panel.
A momentary dry contact closure from the 735/737 relay is used to activate the breaker
trip coil in the event of a fault. To help determine the cause of a trip, separate indicators
are provided for phase instantaneous, phase time overcurrent, ground fault
instantaneous, and ground fault time overcurrent. These latched indicators remain set
after a breaker trip. They can be reset by the front panel CLEAR button.
A special feature of the 735/737 named "Trip Record" is the ability of the relay to
sequentially display the last five causes of trips. To display the trips, press and hold the
reset key. After 2 seconds, the front panel indicators will display the last 5 trips starting
with the most recent.
The 735/737 has separately adjustable instantaneous and time overcurrent pickup levels.
No intentional delay is added to the instantaneous trip. Five separate time overcurrent
curve shapes can be selected: definite time, moderately inverse, normal inverse, very
inverse, and extremely inverse. For each curve shape, 40 different curves to produce
different time delay levels can be selected using the time multiplier settings and curve
shift. These allow selection of optimum coordination with fuses, feeders, motors, trans-