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Operational issues could arise on a distribution network if a third-party aggregator controls a large number of the network’s loads without visibility of network states or topology. This paper investigates mechanisms by which an aggregator could coordinate with a distribution network operator such that aggregate load actions do not negatively impact the network. We propose two possible frameworks for coordination and develop a specific coordination scheme in which the operator can partially block the aggregator’s control inputs to loads. We design a control strategy for the aggregator assuming it has little to no information about how the operator is blocking its control. The proposed controller estimates the number of loads that are not receiving the aggregator’s commands and compensates accordingly. In a simulation study, the proposed controller consistently outperforms a benchmark controller in terms of average tracking error.
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Strategies for Network-Safe Load Control with a Third-Party Aggregator and a Distribution Operator
When providing bulk power system services, a third-party aggregator could inadvertently cause operational issues at the distribution level. We propose a coordination architecture in which an aggregator and distribution operator coordinate to avoid distribution network constraint violations, while preserving private information. The aggregator controls thermostatic loads to provide frequency regulation, while the distribution operator overrides the aggregator’s control actions when necessary to ensure safe network operation. Using this architecture, we propose two control strategies, which differ in terms of measurement and communication requirements, as well as model complexity and scalability. The first uses an aggregate model and blocking controller, while the second uses individual load models and a mode-count controller. Both outperform a benchmark strategy in terms of tracking accuracy. Furthermore, the second strategy performs better than the first, with only 0.10% average RMS error (compared to 0.70%). The second is also able to maintain safe operation of the distribution network while overriding less than 1% of the aggregator’s control actions (compared to approximately 15% by the first strategy). However, the second strategy has significantly more measurement, communication, and computational requirements, and therefore would be more complex and expensive to implement than the first strategy.
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- Award ID(s):
- 1837680
- PAR ID:
- 10309792
- Date Published:
- Journal Name:
- IEEE transactions on power systems
- ISSN:
- 1558-0679
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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