Fault-tolerant generator telecontrol over a microgrid IP network

Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection

“…It seems likely that the backbone for such an infrastructure will be the "utilities intranet": a data network which is common to the utilities but separate from the Internet, which is envisioned to allow for the eventual connection of all regional substations, equipment, and CCs throughout the grid [16,17]. Standard best-effort IP links cannot provide the required QoS and network availability requirements to ensure low-latency, low-jitter communications over multiple hops [2,18]. For a supply or generation utility degraded load following results in an inability to meet contractual power requirements, and in the worst-case it may result in the tripping of frequency protection devices and unintentional islanding should spinning reserves be unavailable.…”

“…To satisfy the varying range of QoS and routing requirements that smart grid traffic requires [19], differentiated services (DIFFSERV) traffic prioritization and enhanced multicast user datagram protocol (UDP) concepts offered by IP version 6 (IPv6) could be leveraged [16][17][18][19][20]. However, such end-to-end QoS management across multiple control areas is still some way off becoming a practical reality.…”

“…End-to-end QoS management is needed for distributed control and protection applications. For instance, the stability of the closed-loop while performing bilateral load following (with sampling rates typically in the range 100-1000 ms) has been found to be highly dependent upon the latency (delay), variability in latency (jitter), and packet losses that the control network induces [2,18].…”

Dependable Control for Wireless Distributed Control Systems

“…They propose an augmented closed-loop DCS and develop an adaptive tracking controller to stabilize the resulting stochastic system. The implementation of such techniques can be non-trivial, and both [23] and [24]-plus closely related methods-require a high-fidelity process model plus knowledge of the network characteristics such as delays and losses. The work in [23] requires the solution to a large non-convex optimization problem, obtained by sweeping the frequency parameter over a specified range using a given search granularity.…”

“…This work ranges from relatively simple first-order hold interpolators to be used in intelligent actuators (e.g., [22]) through to advanced techniques based upon H ∞ filtering of the data stream, application of adaptive sampling controls, and the use of buffering schemes within a robust control framework (e.g., [23,24]). In [23], the use of playback buffers in conjunction with information redundancy is suggested to overcome packet losses, packet disordering and variable latency of UDP/IP communication links in a closed loop. Buffer sizes should be selected to cover worst-case latencies of the links and in the absence of other methods can be estimated based upon gathered statistical data.…”