Provision of Supplementary Load Frequency Control via Aggregation of Air Conditioning Loads

Abstract

Abstract:The integration of large-scale renewable energy poses great challenges for the operation of power system because of its increased frequency fluctuations. More load frequency control (LFC) resources are demanded in order to maintain a stable system with more renewable energy injected. Unlike the costly LFC resources on generation side, the thermostatically controlled loads (TCLs) on the demand side become an attractive solution on account of its substantial quantities and heat-storage capacity. It generally contains air conditioners (ACs), water heaters and fridges. In this paper, the supplementary LFC is extracted by the modeling and controlling of aggregated ACs. We first present a control framework integrating the supplementary LFC with the traditional LFC. Then, a change-time-priority-list method is proposed to control power output taking into account customers' satisfaction. Simulations on a single-area power system with wind power integration demonstrate the effectiveness of the proposed method. The impact of ambient temperature changes and customer preferences on room temperature is also involved in the discussion. Results show that the supplementary LFC provided by ACs could closely track the LFC signals and effectively reduce the frequency deviation.

Optimal Dispatch of Aggregated HVAC Units for Demand Response: An Industry 4.0 Approach

“…A minimum-variance (MV) statistical control law is derived to follow a one-step-ahead load signal and is demonstrated to perform well under simulation with 10,000 TCLs. Zhou et al [18] developed a change-time-priority-list method to control power output taking into account customers' satisfaction for the aggregation of multiple HVAC systems to provide demand-side frequency regulation services, to support intermittency of renewable generation, e.g., in the presence of fluctuating wind power. The aggregation unit employs simple approximations for on/off change times in the HVAC units to prioritize their dispatch in order to follow load control signals.…”

“…where the dot above a variable represents its first derivative (d/dt), D ≥ 0 represents any dead-time in the converter dynamics, τ is the thermal time constant of the converter and K T is the equivalent thermal gain of the converter. A model such as this has previously been studied in the context of HVAC control for demand response applications, and time constants of 10-30 min and dead-times between 0-5 min are typical of most buildings [17][18][19][20]. In Equation 1, the sign of K T distinguishes between a heating (positive) or cooling (negative) application.…”

Progressive time-differentiated peak pricing (PTPP) for aggregated air-conditioning load in demand response programs

“…The decision variables are the PTPP state variables, u i,t , and the coefficient by which the baseline electricity price is multiplied in the control periods for LA i, Δp i,t . Min ∑ Γ t¼1 L AC;t −L ACbase;t −L t arget;t À Á 2 (11) subject to: Equations 7 to 10…”

“…7 From the perspective of customers, they can reduce electricity costs by adjusting the end-use load. 8,9 For example, customers can dim spare lights, 10 adjust air-conditioning (AC) temperature settings, 11 or directly shut down unimportant electrical equipment. 12 Yin et al 13 proposes a strategy to reduce peak load under CPP by controlling electrical vehicles.…”

Multi-Time Scale Control of Demand Flexibility in Smart Distribution Networks

“…Authors in [6][7][8][9][10][11][12][13] proposed various control algorithms and strategies for utilizing EVs flexibility for system balancing purposes. In particular, supplementary load frequency control using aggregated devices (e.g., EVs [6], EVs and heat pumps [7], air-conditioners [8], and residential water heaters [9]) are developed to exploit EV flexibilities for system level balancing. Similarly, the performance of an aggregated V2G and an area control error approach for providing frequency regulation are demonstrated in [10,12].…”