• Priority Load Control
• Manual Paralleling Controls
• DC Control Power Selector - Best Battery System
• System Test Switch
• Programmable Status Panel
• Master Audible Alarm
• Paralleling Bus Metering / Digital Data Monitor
• Master Control Programmable Logic Controller (PLC)
• Operator Interface

Load shedding is done on a last-on, first-off basis. The generator bus has a solid-state frequency monitor with integral time delay to initiate load shedding upon a reduction of bus frequency to 58 Hz or less, for a period of two seconds or more. Upon sensing a bus under-frequency, the system automatically sheds the lowest priority load connected at the time of occurrence. This shed circuit overrides any manual load-add operation and locks out the manual load-add circuitry. It gives a visual and audible alarm annunciation of bus under-frequency load shed condition. A “bus under-frequency reset” push-button is provided to reset bus under-frequency load shed signal.

A “load shed bypass/reset” push-button for manual supervised operation over the load-shed, load-add control logic is provided. One push-button is provided for each priority block except first priority. Logic is provided in the event that a bus overload occurs resulting in a reduction in bus frequency; the bypassed priority load is shed automatically through override logic control.

The solid-state sync check relay is furnished for manual paralleling; to sense and compare the phase angle difference between the oncoming generator and the bus. This relay locks out the manual paralleling push-button until the oncoming generator is within 15 degrees of synchronism.

Operation is arranged so the operator can depress and hold the manual paralleling push-button. When the relative phase angle reduces to 15 degrees and going towards zero degrees, the sync check relay’s output contact initiates the closing of the respective oncoming generator breaker.

All manual paralleling interface controls and metering are grouped in a central location on the front of the master control section. This feature allows for multiple generators paralleling from one location within the switchgear.

A single DC-to-DC converter provides a constant 24VDC power to the generator and master programmable logic controllers (PLC's) during starting and cranking of all engine generator sets “simultaneously”. Additionally, the best battery system provides power to each generator paralleling circuit breaker trip coil if the generator battery power is lost to its cubicle.

Supported Functions

• Manual Paralleling Available -- the light goes out when the generator of the breaker selected from the plant selector switch is in sync with the bus.
• Bus Under-frequency Alarm.
• Load Shed Circuits Activated (One for each priority) -- a priority block of ATS’s that are connected to the de-energized normal side.
• Load Shed Bypass (One for each priority) -- a priority block of ATS’s which should be shed to the de-energized normal are connected to emergency.
• Engine Generator Status Lights (One set for each Engine Generator)
• Running
• On Line
• Lockout
• System PLC Stopped
• PLC Power Source Failure -- a loss of the output from the DC/DC converter.
• Emergency Mode -- occurs when normal power is lost to one of the ATS’s.
• Load Demand Active
• Bus Optimization Active
• Bus Loaded to Capacity
• Bus Optimization Stopped

• Current input: 0 - 5 A AC nominal
• Voltage input: 0 - 600 V AC nominal
• Frequency range: 40 - 100 Hz fundamental - True RMS measurements up to and including the 17^th harmonic.
• The following parameters can be read from the LCD display: line to line / line to neutral voltage, current on each phase (I_A, I_B, I_C), Kilowatt per phase and total (KW_A, KW_B, KW_C, KW_T), Reactive power, and KVAR per phase.
  

• The CPU has a minimum of 16K/Bytes capable of storage on random access memory (RAM), erasable programmable read only memory (EPROM), or electrically erasable programmable read only memory (EEPROM). RAM memory is backed up with a lithium battery for protection during voltage loss and spare parts capabilities.
• The CPU is also capable of supporting I/O and CPU fault diagnostics. This consists of CPU failure detection, watchdog timer error, I/O modular failure, and battery failure.
• The CPU has an execution speed of 4 milliseconds per 1000 words of latter logic programming.
• The PLC has the capability to utilize up to 1024 discrete I/O points and 2048 memory registers.
• The PLC has the capability to interface to a remote I/O rack via RS-485 serial communication.

The video panel is compatible with major PLC brands and connects directly to the PLC/CPU communication port over RS-422 communications. For possible future remote operator interface stations, this product also supports the addition of multiple video panels networked either through a multi-drop configuration or through the addition of a PLC communications card.