Optimizing Data Access for Wind Farm Control over Hierarchical Communication Networks

Abstract

We investigate a centralized wind farm controller which runs periodically. The controller attempts to reduce the damage a wind turbine sustains during operation by estimating fatigue based on the wind turbine state. The investigation focuses on the impact of information access and communication networks on the controller performance. We start by investigating the effects of a communication network that introduces delays in the information access for the central controller. The control performance as measured by accumulated fatigue is shown to be significantly impacted by communication delays and also by the choice of the time instances at which sensor information is accessed. In order to optimize the latter, we introduce an information quality metric and a mathematical model based on Markov chains, which are compared performance-wise to a heuristic approach for finding this parameter. This information quality metric is called mismatch probability, mmPr, and is used to express quantitatively the information accuracy in a given scenario. Lastly, measurements of different communication technologies have been performed in order to carry out the analysis in a practically relevant scenario with respect to the communication network delays. These measurements are done in regard to packet loss and communication delays, and the simulations are rerun using either the traces from the measurements or scenarios constructed from the delay parameters.

A Consecutive Power Dispatch in Wind Farms to Mitigate Secondary Frequency Dips

“…However, communication of each WTG is required with a central WF controller. A latency time of 200 ms [29] between action of two frequency support modes from two groups of WTGs is caused by communication networks and computation time. Fig.…”

Approximation of the Time Alignment Error for Measurements in Electricity Grids

“…The impact of timing in access to measurement information in distributed systems has earlier been analyzed in [6] and such analysis put into context of different electricity grid applications in [8], [9] and also in generalized networked control applications [10]. This paper instead focuses on the deviations of a measurand caused by time alignment deviations at the sensor.…”

Impact of time interval alignment on data quality in electricity grids

“…The impact of timing in access to measurement information in distributed systems has earlier been analyzed in [4] and such analysis put into context of different electricity grid applications in [7], [8] and also in generalized networked control applications [11]. This paper instead focuses on the deviations of a measurand caused by time alignment deviations at the sensor.…”