By automating existing power equipment, our load preservation controls seek the utility source, control breakers, and keep the electrical system operational. This is accomplished by monitoring frequency and power sources from utility plus generation capacity versus total circuit load then dynamically determining the prioritized load trip sequence for non-critical loads so as not to overload generator when separation from utility occurs.

• High speed load shed
  
• Pre-armed shedding schemes
  
• GPS time synchronization
  
• Sequence of events recorded events (within 1 ms)

Using master and localized industrial rugged MODBUS PLCs, each controller is pre-configured with load priority lists that are optimized to minimize (or maximize) the number of loads tripped, the total kW shed and the adherence to the priority list. Localized frequency-based backup controllers give the load preservation scheme redundancy at local level performing even if communication network is down.

The MODBUS controllers provide:

• Redundancy and high performance
  
• Redundant DC power supply
  
• Ensure reliable installation in even the most difficult plant environments
  
• Can use available DC control power to avoid installation of AC power
• IEEE rated to trip DC breaker coils, I/O available with DC common, and fast current output to switch 30A
  
• 0–1 mV analog input
  
• Standard sequence of events modules with 1ms time stamp accuracy

• TEST mode scenarios allow simulation and recording without the actual tripping of circuit breakers
  
• Manual control capability to close and trip circuit breakers
  
• Generator control interface provides ability to send signals to generator controls upon power disruption
  
• Data validation techniques provide limit checking, consistency, and averaging to determine accuracy of measured data
  
• Diagnostic parameter recording provides event reconstruction for troubleshooting purposes including 1ms event stamping to enable root cause analysis to minimize downtime.
  
• Demand control limits imported kW demand in case of loss of one or more generators and reduces utility charges by negotiating for interruptible rates

Sequential Events Recording, Cogeneration Monitoring, Load Preservation, Utility Monitoring

Outages typically cause $2-10 million annually for refineries without monitoring systems. Restoration can be slow and inefficient causing even greater disruption to the process and costly production losses. Monitoring to record sequential events to 1 millisecond allows immediate response to incidents and root cause analysis to minimize downtime.

Co generation provides an alternate supply of power, but the system should be monitored in case of an outage due to overload, utility frequency collapse, poor co-ordination, relay maintenance, or human error. Monitoring the alternate supply system assures it is available when you need it.

In the event of a power loss from the utility or on-site generation, power monitoring can initiate a load preservation system that responds by shedding lower priority loads in order to keep the remaining sources of power from falling. The environmental impact, such as gas emissions, can also be minimized through load preservation.