Distributed Generation
Distributed Generators are a viable source of demand response assets for a utility. They can be bid into the ISO markets as non-spin reserves, provide contingency power, and be used to offset capacity shortages. Utilities are building programs to aggregate customer-owned generators into blocks that can be bid into the energy markets.
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Large Generation Units (5,000-300 kW)
These are generally custom designed for the specific installation and may include sophisticated ramping in/out schemes, relaying and synchronization. From a utility standpoint, the larger the generator load, the more impact the operation of the unit will have on the utility power system.
The units have sophisticated protection, operation/synchronization, and interconnect systems. Cooper Power Systems solution for Large Distributed Generators is an RTU capable of communication to an external PLC as shown in the following figure:
The communication from the Yukon Master Station to the Distributed Generation units is done using DNP 3.0. The RTU provides a start/stop relay control pair, and analog and status inputs for connecting any discrete IO points. The unit can communicate to the distributed generators PLC or to IEDs located at the site. The unit also supports the direct connection of a sub-meter.
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Medium Generation Units (300-50kW)
These units contain protection hardware and a parallel/synchronization device. In these installations, the utility is primarily interested in starting the devices and the status of the transfer switch. The Cooper Power Systems solution for Medium Distributed Generators is an RTU with discrete I/O as illustrated in the following figure:
The communication from the Yukon Master Station to the Distributed Generation units is done using DNP 3.0. The RTU provides a start/stop relay control pair, and analog and station inputs for connecting any discrete IO points. Meter data can be acquired from the site meter. Yukon can directly query this meter to validate the load drop at the facility.
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Small Generation Units (<50kW)
In general, these units are fully packaged solutions with standard synchronization and under-frequency contactors. Small units are designed to provide load to the critical components of a business.
Small Generation Units have simple protection hardware. In these installations, the utility is primarily interested in starting the device and validating at load drop at the site. The Cooper Power Systems solution for Small Distributed Generators is a paging LCR with a start/stop control relay as shown in the following figure:
The communication from the Yukon Master Station to the Distributed Generation unit is done using the flex paging communication to minimize communication and site installation costs. The RTU provides a start/stop relay control pair. The site Utility Meter is polled to verify that there is a load reduction at the site.
