Automatic Coordination of Internet-Connected Thermostats for Power Balancing and Frequency Control in Smart Microgrids

Abstract

This paper proposes a novel feedback control strategy, so-called clock-like controller (CLC), to balance power supply and demand in smart microgrids by adjusting the setpoint temperatures of air conditioning (AC) loads. In the CLC algorithm, the grid operator communicates with the individual thermostats via the Internet and adjusts their setpoints by discrete temperature intervals (e.g., ±0.5 °C). Numerical simulations indicate that the proposed algorithm is able to deliver a smooth controllability of the aggregate AC power despite discrete temperature offsets. It can also be used for peak load shedding to mitigate the power generation cost. The CLC algorithm is then integrated into the grid frequency control problem, in which both power generators and loads in the network attempt to regulate the frequency of the system despite disturbances from demand, renewable sources, and local weather conditions. An autonomous microgrid model including a steam and a hydro generator, a solar energy source, and a large number of thermostatic loads is developed to evaluate and demonstrate the proposed method. Simulation results indicate that the AC loads with CLC algorithm can help maintain the power system frequency during extreme events when demand exceeds the maximum generation capacity available to the network. Under normal conditions, the contribution of demand-side control is marginalized by the fast responding generators, because of time delays in the frequency measurement and internet communication network.

Decentralized Frequency Control using Packet-based Energy Coordination

“…Several packet-based energy management systems have been proposed to coordinate DERs [13], [14], [15]. In packet based systems, loads request for energy packets with given duration and amount.…”

Fast Transactive Control for Frequency Regulation in Smart Grids with Demand Response and Energy Storage

“…The aggregate power demand response of TCLs to setpoint input is similar to that of a linear underdamped second-order system [29]. Both linear and nonlinear controllers have been used to achieve power tracking and frequency regulation [29][30][31][32][33]. Most of these controllers have a common element of using an integral controller.…”

Parametrización del esquema de disparo de generación ante eventos de sobrefrecuencia en un sistema eléctrico utilizando técnicas de optimización / Parametrização do esquema de disparo de geração em resposta a eventos de sobrefrequência em um sistema elétrico usando técnicas de otimização

“…El esquema en mención, además de considerar los casos específicos en los cuales los sistemas eléctricos de potencia sean propensos a tener o presentar problemas por sobrefrecuencia tal y como señala [5], [8], [9], [21], considera un algoritmo mediante el cual, se plantea tener un despacho de generación óptimo con la finalidad de reducir los costos operativos [15], [22].…”

“…Es necesario mencionar que, la tasa de incremento de la frecuencia es de naturaleza oscilatoria establecida por los generadores que se encuentran conectados al sistema de transmisión [2], [3], [19]. Si no existen acciones de los gobernadores o algún tipo de control, el valor de esta frecuencia podría llegar a estabilizarse en valores mayores al nominal según se menciona en [3], [17], [21]. De una u otra manera la frecuencia resultante seria mayor, lo cual provocaría una mayor pérdida de carga antes de prever algún tipo de acción correctiva, con lo que el colapso del sistema sería inminente [24].…”