Basler Electric BE1-25A - Manual (Page 11)

SECTION 1
• GENERAL INFORMATION
DESCRIPTION
A basic BE1-25A Auto-Synchronizer consists of three rack-mounted modules that determine the proper
time to initiate closing of a breaker to parallel a generator and a bus. The three standard modules are the
master control unit (MCU) sync module, the test module, and the power supply. Optional plug-in modules
are available for installation (at initial purchase, or at any later time) to enhance this basic capability.
Among the options are the frequency matching and voltage matching modules that direct the generator
control system to adjust voltage or frequency (or both) to meet system requirements. The unit is not truly
an automatic synchronizer unless one or more of the matching options is incorporated.
An ideal closing is one that minimizes electrical and mechanical transients. Because the ideal closing
occurs when the voltages are in phase, the initiating signal must be delivered ahead of phase coincidence
by a factor equal to the operating speed of the breaker. This factor (termed the advance angle) is
calculated by the MCU sync module. This module is essentially a dedicated computer that monitors the
voltages on both sides of the breaker to be closed, calculates the slip frequency, and then (taking into
consideration the operating speed of the breaker) calculates the required advance angle.
Closure will occur only if the slip frequency is less than the limit established by the slip setting. Once
breaker closure has been initiated, the BE1-25A is inhibited from further operation for a minimum of 15
seconds. If the breaker reopens during this 15-second inhibit period, the unit enters a lockout condition
that prevents further operation until the unit is reset.
OPTIONS
Plug-in options can extend the capability of the basic unit. These are briefly summarized here as to
overall function. (They are explained in detail in the later sections of this manual.)
• A voltage acceptance module may be added to the basic synchronizer to assure that the
oncoming generator voltage is within a pre-selected magnitude with respect to the bus voltage
before breaker closure is allowed. This option is required if one of the voltage matching modules
is to be used.
• Voltage matching modules provide RAISE and LOWER signals to the voltage regulator of the
oncoming generator to bring the machine voltage within the limits defined by the voltage
acceptance module.
• Frequency matching (i.e., speed control) module provides RAISE and LOWER signals to the
governor to bring the oncoming generator speed to within the slip frequency limit that is preset
into the Auto-Synchronizer. If the slip is very small and the phase angle is large, a target pulse is
initiated to change the generator speed in the direction of the closest phase coincidence.
• A dead bus module allows selection of various low bus voltage conditions to enable breaker
closing without synchronization. This provides a black start capability for the system.
MULTI-GENERATOR OPERATION
BE1-25A relays can control more than one generator by simultaneously switching all of the relay relevant
inputs and outputs from one generator to the next. Those inputs and outputs are: the generator sensing
voltage, breaker 52b and closing coil circuits, and the leads associated with options (such as the
frequency and voltage matching lines to regulator or governor). All of these must be switched
simultaneously by a ganged switch called the synchronizing select switch. (This switch is installed
external to the BE1-25A unit, and is not supplied with the relay. Installation details are given in Section 4,
Installation.)
In addition to the relay relevant inputs and outputs, settings for the system operational parameters are
entered using the MCU front panel LOAD/FUNCTION select switch. Settings for six generator systems
can be entered and stored into MCU memory.
9146600990 Rev S BE1-25A General Information 1-1