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889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
1–1
889 Generator Protection System
Chapter 1: Introduction
GE
Grid Solutions
Introduction
The Multilin 889 relay is a microprocessor-based unit intended for the primary protection
of small, medium and large sized generators. Base relay models provide standard
generator protection functions plus a number of current and voltage based backup
functions.
Overview
The relay features generator unbalance, generator differential, over excitation, loss of
excitation, 3rd harmonic neutral undervoltage, over and under frequency, synchrocheck
and other essential functions with a basic order option. Additionally available with an
advanced order option are overall differential (to protect the transformer-generator
combined), directional overcurrent elements, restricted ground fault, 100% stator ground,
out-of-step protection, rate of change of frequency, power factor, harmonic detection,
frequency out-of-band accumulation and others. An optional RTD module allows for
thermal protection and monitoring. An optional analog inputs/outputs module allows for
monitoring of generator excitation current, vibration and other parameters.
These relays contain many innovative features. To meet diverse utility standards and
industry requirements, these features have the flexibility to be programmed to meet
specific user needs. This flexibility will naturally make a piece of equipment difficult to
learn. To aid new users in getting basic protection operating quickly, setpoints are set to
typical default values and advanced features are disabled. These settings can be
reprogrammed at any time.
Programming can be accomplished with the front panel keys and display. Due to the
numerous settings, this manual method can be somewhat laborious. To simplify
programming and provide a more intuitive interface, setpoints can be entered with a PC
running the EnerVista 8 Setup software provided with the relay. Even with minimal
computer knowledge, this menu-driven software provides easy access to all front panel
functions. Actual values and setpoints can be displayed, altered, stored, and printed. If
settings are stored in a setpoint file, they can be downloaded at any time to the front panel
program port of the relay via a computer cable connected to the USB port of any personal
computer.