Basler Electric BE1-32R - Manual (Page 11)

SECTION 1 • GENERAL INFORMATION
INTRODUCTION
BE1-32R, Directional Overpower and BE1-32O/U, Directional Over/Underpower Relays sense real power
(IE times the cosine of θ). These solid-state relays are designed for use in single- or three-phase systems
to protect equipment against overpower and/or underpower conditions. They may also be used in the
supervisory control of circuits.
APPLICATION
Directional Power Relays are typically used in applications where excessive power flow in the tripping
direction is bad. Over and/or underpower protection is desirable where:
•
Power flows into a generator, indicating loss of prime mover torque (motoring).
• Power flows into the secondary of a station distribution transformer, indicating an industrial or private
customer is supplying power into the utility system.
• Excessive load has been connected to a system.
• Overload has been placed on a distribution system.
• Overspeeding is a prime concern.
• An open breaker creates an overload on a local generation facility.
• Loss of excitation can be determined by var sensing.
Example 1: Anti-Motoring
When a synchronous generator, operating in parallel
with a power system, loses prime mover torque, it
remains in synchronism with the system and continues
to run as a synchronous motor. Motoring draws power
from the system to drive the prime mover and can cause
severe damage to the prime mover. Steam turbines
require a constant flow of steam to remove the heat
caused by turbulence or cavitations on or about the
blades. Without this flow of steam, heat builds up and
may cause softening or distortion of the turbine blades.
Diesel engines and gas turbines are less susceptible to
immediate damage, but unburned fuel may present a fire
or explosion hazard.
BE1-32 Directional Power Relays can detect power flow
into the generator and disconnect the generator before
the prime mover sustains inevitable damage. Unlike the
conditions arising from faults, the electrical conditions
involved in anti-motoring protection are balanced.
Therefore, single-phase relay protection is adequate.
Figure 1-1 shows connections for single-phase relay
(type B or V sensing). This connection measures real
power if the system voltages are balanced.
The BE1-32R, Reverse Power Relay must be sensitive
enough to detect power levels lower than those required
to motor the generator. Sensitivity is much more
important on steam and hydro turbines than on
reciprocating engines and gas turbines.
Figure 1-1. Single-Phase
Motoring Protection
NOTE
This product is not recommended for power factors below 0.10. Contact Basler
Electric for recommended products.
9171100990 Rev T BE1-32R, BE1-32O/U General Information 1-1