Accommodating High Levels of Variable Generation - NERC

Characteristics of Power Systems & Variable Generation
• Appropriate test procedures should be developed to comply with NERC model validation and
performance verification requirements (such as reactive limits).
There is a need to develop and deploy valid, generic, non-confidential, and public standard
power flow and stability (positive-sequence) models for variable generation technologies. Such
models should be readily validated and publicly available to power utilities and all other industry
stakeholders. Model parameters should be provided by variable generation manufacturers and a
common model validation standard across all technologies should be adopted. Recommended
NERC and Industry actions to address these needs are:
NERC Action: Standard, valid, generic, non-confidential, and public, power flow and
stability models (variable generation) are needed and must be developed, enabling
planners to maintain bulk power system reliability. The NERC Planning Committee
should undertake a review of the appropriate Modeling, Data and Analysis (MOD)
Standards with a view towards improvements required to simulate high levels of variable
generation. Feedback to the group working on NERC Standards’ Project 2007-09 will be
provided.
Industry Action: Industry activities (e.g. those of the Institute of Electrical and Electronic
Engineers (IEEE) and Western Electricity Coordinating Council (WECC)) on short
circuit and dynamic models should be supported and encouraged. Variable generation
vendors need to be familiar with the NERC’s Modeling, Data and Analysis (MOD)
Standards and materials which explain their intent and purpose. Further, industry should
develop appropriate test procedures to comply with NERC model validation and
performance verification requirements (such as reactive limits).
Variable generation plants are often located in remote areas of the network where the shortcircuit
level is weak and, as a result, problems such as under-/over-voltages, harmonics or
voltage unbalances may be observed. Furthermore, controls for variable generation located near
HVDC interconnections or near series compensation may interact with such equipment. 45
Therefore, variable generation manufacturers’ detailed 3-phase equipment level models are also
needed to support specialized studies under these and other circumstances. The task force
recommends:
Industry Action: The variable generation manufacturers should support the development
of detailed 3-phase models required for special system studies.
45 CIGRE Technical Brochure 328, Modeling and Dynamic Behavior of Wind Generation as it Relates to Power
System Control and Dynamic Performance, Prepared by CIGRE WG C4.601, August 2007 (available on-line at:
www.e-cigre.org)
Accommodating High Levels of Variable Generation 32