Basler Electric BE1-81O/UT3EE1KA7N1F / BE181OUT3EE1KA7N1F Digital Frequency Relay

Introduction

BE1-BPR Breaker Protection Relays are three-phase and neutral,

microprocessor based relays designed to provide power systems

with protection and security against monitored breaker failure or

to initiate multiple shot breaker reclosings.

These relays incorporate a powerful means of programming internal

relay logic to satisfy a wide range of user requirements without

making any relay hardware changes. Microprocessor-based design

provides the basic features of a programmable logic controller (PLC)

combined with an instantaneous overcurrent module.

Cased in a 19 inch rack-mount or a vertical panel mount, the relay

offers installation versatility. A wide temperature, 2 lines by 16

character display provides diagnostic and setup information. 

Two RS-232 serial ports (one each front and rear) and one RS-485

serial port (rear) provide remote communication and relay control.

Built-in diagnostics and monitoring features provide information for

both the health of the relay and the health of the breaker being

monitored. Relay diagnostics include continuous background monitoring

of the power supplies, analog-to-digital (A/D) converter, random-access

memory (RAM), read-only memory (ROM), and electrically-erasable

programmable ROM (EEPROM). A dedicated alarm (ALM) relay output

provides power supply, microprocessor, and software alarm status.

Breaker diagnostics include a timing diagnostic log, breaker contact duty

monitoring, breaker resistor protection, and breaker arc detection.

Other monitoring features include oscillographic fault records and fault

summary logs. BE1-BPR relays use the Inter-Range Instrumentation Group

(IRIG), Format B for high timing accuracy and resolution.

BE1-46N Negative Sequence Overcurrent Relays are three-phase solid

state relays designed to provide protection for generators and motors

from unbalanced loading or power system faults. These relays protect

the machinery from damage when the protective scheme or other

equipment, external to the generator, fails to eliminate the unbalanced

condition.

BE1-46N Negative Sequence Overcurrent Relays accurately monitor the

magnitude and control the duration of the negative sequence current

component. These relays incorporate a time delay that replicates the

machinery heating and cooling characteristics.

An alarm element in the relays may be used to provide time to locate

and isolate the fault. Doing this avoids damage to the machinery, prevents

an undesired trip, and precludes a potentially prolonged outage of the

machinery.

BE1-46N relays are designed for use with any poly-phase generating

system having known (I2)2t limits between 1 and 99. Relays that operate

using phase currents to determine the negative sequence component are

phase rotation sensitive. BE1-46N relays are phase rotation sensitive.

Principles of Symmetrical Components

Principles of symmetrical components allow an unbalanced system to be

considered as three separate, balanced subsystems. These balanced

subsystems may then be analyzed as single phase quantities.

These quantities are the positive, negative, and zero sequence components

of current and voltage.

The positive sequence component of current (I1) represents the portion of

the total current which has normal phase rotation and produces no adverse

effect on the system. An ideally balanced system contains only positive

sequence phase currents and voltages.

The zero sequence component of current (I0) also has no adverse effect

on a three-phase, three-wire (no neutral connection) power system because

it produces no appreciable magnetic flux and causes no excessive heating

in the generator rotor or windings.

The negative sequence component of current (I2) produces a magnetic flux

in the stator that has the same rotational speed as the rotor flux, but in the

opposite direction. This causes the stator magnetic flux to rotate at twice

the system frequency and induce eddy currents into the rotor. These eddy

currents create excessive heat in the rotor iron and windings, and, if allowed

to persist, could result in severe damage to the system.