9328900990 Rev L BE1-951 General Information 1-3
including intertie protection (interconnects between an electric utility and a source of non-utility
generation). The power measurement algorithm is adapted as appropriate for any possible three-phase or
single-phase voltage transformer connection. Directional Power is calibrated on a three-phase basis
regardless of the voltage transformer connection used.
Frequency Protection
Six over/underfrequency protection function blocks are provided: 81, 181, 281, 381, 481, and 581. Each
function block can be set for overfrequency or underfrequency operation.
Breaker Failure Protection
One breaker failure protection block (BF) provides programmable breaker failure protection.
Fuse Loss Protection
A fuse loss function protects against false tripping due to a loss of voltage sensing.
General Purpose Logic Timers
Two general-purpose logic timers (62, 162) with six modes of operation are provided.
Setting Groups
Four setting groups allow adaptive relaying to be implemented to optimize BE1-951 settings for various
operating conditions. Automatic and external logic can be employed to select the active setting group.
Virtual Control Switches
BE1-951 virtual control switches include one virtual breaker control switch and four virtual switches.
Trip and close control of a selected breaker can be controlled by the virtual breaker control switch (101).
The virtual breaker control switch is accessed locally from the front panel human machine interface (HMI)
or remotely from the communication ports.
Additional control is provided by the four virtual switches: 43, 143, 243, and 343. These virtual switches
are accessed locally from the front panel HMI or remotely from the communication ports. Virtual switches
can be used to trip and close additional switches or breakers, or enable and disable certain functions.
Virtual Lockout Protection
The BE1-951 includes two virtual lockout functions (86 and 186) that emulate electric reset lockout relays
and operate as a simple flip/flop. When the trip input is asserted, the output of the function toggles to the
true state and when the reset input is asserted, the output of the function toggles to the false state. If both
inputs are asserted at the same time, the trip input always has priority. The state of the lockout (latch) is
stored in non-volatile memory.
Metering Functions
Metering is provided for all measured currents, voltages, and frequency and all derived neutral and
negative-sequence currents and voltages. Three phase watts, vars, and power factor is provided. Per
phase watts and vars is also provided when the VT connection is 4W.
Reporting and Alarm Functions
Several reporting and alarm functions provide fault reporting, demand, breaker, and trip circuit monitoring,
as well as relay diagnostic and firmware information.
Energy Data Reporting
Energy information in the form of watt-hours and var-hours is measured and reported by the BE1-951.
Both positive and negative values are reported in three-phase, primary units.
Relay Identification
Two free-form fields are provided for the user to enter information to identify the relay. These fields are
used by many of the reporting functions to identify the relay that the report is from. Examples of relay
identification field uses are station name, circuit number, relay system, purchase order, and others.
Clock
A real-time clock is included with a capacitor backup and is available with an optional battery backup.
Depending upon conditions, capacitor backup maintains timekeeping during an eight to 24 hour loss of
operating power. Battery backup maintains timekeeping when operating power is removed for five years
or longer.
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General