GE Multiline™ 469 Motor Management Relay

This digital relay shall be capable of providing motor protection and management functions.

Its main protection function shall be thermal modelling, which consists of the following 4 main components:

- Overload curve

- Negative sequence unbalance/single phase offset

- RTD offset (hot/cold motor compensation)

- Motor cooling time constant

Special attention should be paid to the protection of the rotor during stall and acceleration. If the rotor is to be protected during stall and acceleration, the

The stall/acceleration curve must be voltage compensated and must be equipped with a speed switch input.

The stator protection thermal model should combine positive and negative sequence currents and RTD winding feedback inputs.

This allows the model to be dynamic at all times, thus allowing the motor load and temperature to be tracked.

The protection functions should include:

- Stall

- Mechanical blocking

- 12 RTD inputs

- Ground overcurrent

- Short circuit

- Differential protection (using CT inputs from both ends of the motor winding (6))

- Voltage transformer input (to provide over-voltage, under-voltage, reverse-phase, over-frequency and under-frequency functions)

The motor management relay shall be fully equipped for power measurement. The event log shall be capable of storing the last 40 events.

It shall be capable of storing 16 cycles of waveform data for each trip occurrence. The relay shall be equipped with an analogue function which is used to test the relay.

The user interface includes:

- A 40 byte vacuum phosphor screen and keypad for access to actual and set values.

- An RS232 port on the front panel for programming the set values.

- an RS485 port using open protocol (selectable baud rate up to 19.200 bps)

- A separate auxiliary RS485 port for increased security or for the exclusive use of maintenance personnel.

- The interface software should be in Windows® format

The relays are of extractable construction for easy testing, maintenance and replacement of parts.