Objective: This project will provide support to the power systems industry in developing test methods, tools, and performance characterization and metrics for time synchronization of system and devices to securely achieve the precision time stamps necessary for grid data and communications applications such as system analysis and diagnosis, system state estimation and distributed multivariate control, and enabling operators to respond to fast dynamic changes (to effectively maintain load and resource balance using distributed energy resources) in the power grid.
What is the new technical idea? Research in the area of improved estimation and control for power systems has recently focused on distribution systems due to significant transformation in distributed energy management technologies. This has been motivated by government and industry requirements for grid efficiency, reliability and resiliency at the distribution level, as well as improvements and increased integration of nonconventional, renewable sources of energy. There is also significant industry interest in improving network stability and load regulation within distribution circuits. All four of these improvements are particularly relevant in the face of decentralized power generation and energy management within microgrids.
The current power grid, however, is not well equipped to handle nontraditional electrical network architecture where generation is not centralized and powerflows may be bidirectional. Further, distribution circuits can potentially operate as islanded microgrids, a fundamentally unique paradigm in the history of grid operations. While there are several challenges in the decentralized generation and regulation of power, a fundamental concern is the real possibility of uncoordinated interaction between microgrid devices resulting in large reactive power flows and other network instability. Timing is an important aspect of network coordination and efforts to guarantee power quality and reliability. Precisely synchronized clocks are needed to:
- ensure fidelity of error and event logs used for diagnosis;
- accurately estimate the state of the system based on its time stamped measurements; and
- develop control algorithms that can apply corrective action in a timely manner.
The new technical idea is that scalable implementation of control and estimation algorithms for large power networks depend on their amenability to decentralization and parallelization, thus requiring precise synchronization between the various interacting components. Timing accuracy is vitally important to fuse data from heterogeneous sources (diagnostics), to make accurate estimates of state (situational awareness) and to ensure safety of decentralized control schemes (situational intelligence). Practical timing considerations are rarely considered during design but pose a significant challenge at the time of implementation.
What is the research plan? The research plan is to develop a set of software tools, along with metrics and guidance on timing requirements and its implications, which will significantly aid industry to integrate future algorithmic improvements in control, estimation and diagnosis.
The plan also includes benchmarking the analysis against highly dynamic aspects of the power network e.g., mitigation of voltage collapse (using VAR compensation) and suppression of switching transients (using high bandwidth demand response), where current decentralized control methods are inadequate. Specifically, the project will focus on applications in the low voltage (<11KV) distribution network or a microgrid, where closedloop time constants are less than one second, requiring clocks accurate to a few milliseconds.
The plan can be organized into the following steps to address some of the timing challenges listed in the NIST report on “Technology, Measurement, and Standards Challenges for the Smart Grid.”
Step1. Continues the support of the IEEE C37.238 Conformance Testing and standards development effort for 61850-9-3 Level 1 and C37.238. Provide support for the conformance testing effort with IEEE Conformity Assessment Program (ICAP) and University of New Hampshire’s InterOperability Laboratory (UNHIOL).
Step2. Augment the testbed with practical use case scenarios based on a survey of priorities with other power systems researchers (IEEE Power Systems Relay Committee (PSRC) Working Group, Smart Grid Interoperability Panel (SGIP), Oak Ridge National Laboratory (ORNL)). As a starting point, use cases will be matched with scenarios listed in the steering committee report, such as, distributed VAR compensation, coordinated peak load mitigation (demand response) and regulation of distributed resources and energy services.
Step3. Integrate state estimation and control algorithms into the testbed via embedded simulations and real hardware (where possible). Timing performance data can be obtained from the hardware already installed in the testbed.
Step4. Develop metrics for assessing the impact of time synchronization on the power systems use case developed in Step2.
Step5. Support the Smart Grid Testbed Cyber Module in developing a cyber testbed environment that enables conformance / interoperability test validation as well as realtime simulation and research in a timeaware network for measurement and control.
Step6. Support the Smart Grid Cybersecurity Team in security testing and detection of vulnerabilities introduced by the timing infrastructure.