Accommodating High Levels of Variable Generation - NERC

Characteristics of Power Systems & Variable Generation
generator owner/operators must ensure procedures, protocols, and communication facilities are
in place so dispatch and control instructions can be communicated to the variable generation
plant operators in a timely manner.
Adequate communication of data from variable generation and enhanced system monitoring is
not only a vital reliability requirement, but is also necessary to support the data analysis posed by
other recommended NERC and Industry actions. In this respect, the deployment of phasor
measurement units (PMUs) may become a vital planning and operational tool 41 and assist in
monitoring the dynamic performance of the power system, particularly during high-stress and
variable operating conditions. PMU deployment can help power system planners, operators and
industry better understand the impacts of integrating variable generation on the grid. 42
The following action is therefore recommended for the NERC Operating Committee:
NERC Action: Balancing areas must have sufficient communications for monitoring and
sending dispatch instructions to variable resources. The NERC Operating Committee
should undertake a review of COM-002, FAC-001 and registry criteria to ensure
adequate communications are in place. Further, as NERC Standards’ Project 2006-06 is
reviewing COM-002, input to this review should be provided. If these standards are
found to be inadequate, action should be initiated to remedy the situation (e.g. a SAR).
2.5. Variable Generation Modeling
Existing NERC system modeling standards require reliability entities to develop comprehensive
steady-state data and reporting procedures needed to model and analyze the steady-state and
dynamic performance of the power system (MOD-011 and MOD-013). Equipment operators are
required to provide steady state and dynamic models (MOD-012) to the reliability entities. This
information is required to build a reasonable representation of the interconnected system for
planning purposes, as stated in MOD-014 and MOD-015. 43 Specifically, models are required to
perform load flow, short circuit, and stability studies necessary to ensure system reliability.
NERC standards also deal with periodic verification of the models, such as required by MOD-
023, which deals with verification of reactive power limits. Highly-detailed models are
sometimes provided by owners, but cannot be passed on to Regional Entities due to their
proprietary nature. However, Regional Entities do require generic models, suitable for power
system studies.
41 “Phasor Measurement Unit (PMU) Implementation and Applications,” EPRI Report 1015511, October 2007 and details for
application potential at http://www.eow2007proceedings.info/allfiles2/162_Eow2007fullpaper.pdf
42 See North American SynchroPhasor Initiative for more information at http://www.naspi.org/
43 http://www.nerc.com/page.php?cid=2|20
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