The main components of a CHP installation each have their own control and monitoring systems, which are interconnected to provide a single integrated system for a CHP package. The system controls usually incorporate condition-monitoring equipment, which provides warnings and automatic shutdown in the event of component malfunction, and which also assists in the long-term management and operation of the plant.
Control systems are now usually based on high integrity programmable logic controllers (PLCs) and include all the metering, control and protection systems required for the safe start-up, operation and normal shutdown of the equipment. All safety interlocks for emergency shutdown are normally hard-wired between the plant items and the main control panel.
A CHP package operates for long periods of time with no control by, or supervision from, site staff. As a result, it is common practice to connect the control and monitoring system to some wider network, such as a Building Management System or, more commonly, to a remote control and monitoring system operated by the supplier or operation and maintenance contractor. There are several advantages to this approach:
- The CHP package can be controlled and monitored by the same system that controls and monitors site heat and electricity use.
- The unit can be stopped and started safely by the wider controls system.
- Fuel consumption and heat and electricity output can be monitored as part of the site’s energy management activities.
Next: Long Term Performance