Advanced Control of Thermostatic Loads for Rapid Frequency Response in Great Britain

Abstract

In the Great Britain power system, reduced system inertia (particularly during low demand conditions) and larger possible infeed loss would make grid frequency regulation extremely challenging in future. Traditional primary frequency response could be insufficient to limit the frequency variation within acceptable range. This paper shows that thermostatically controlled loads (TCLs) (domestic refrigerators) can be controlled without real-time communication and in a non-disruptive way to collectively enhance the network frequency response. The aggregated power consumption of TCLs, distributed across the system, could be controlled as a 'linear' function of the locally measured frequency and its rate of change. Alternatively, their aggregated consumption could be made to follow a 'pre-set' power profile depending on the estimated infeed loss. A novel technique for accurate estimation of infeed loss and consequent post-fault TCL power reduction is also proposed. The effectiveness of the two TCL control strategies are compared for primary and secondary frequency response through a case study on a 36 busbar reduced equivalent of the Great Britain power system. The effect of spatial variation of transient frequencies and the time delays in frequency measurement and filtering are considered to show how the TCLs can realistically provide rapid frequency response.

A Load control method with reactive power control capability and enhanced flexibility based on smart load

“…22(a)), whose NCL-rated powers are respectively Table II. Three converter #As are shown, labeled (4), (5), and (6); three converter #Bs are shown, labeled (7), (8), and (9). DSP F28335 is chosen to be the bottom-layer controller, labeled (10), (11), and (12), where the chip IR2110 (label (13)) is chosen to be incorporated with DSP F28335 to drive converters.…”

“…Therefore, DSM has become a popular topic in the field of electrical engineering. V. Trovato proposed a DSM method for the system frequency response with constant temperature loads [5]. A. Gholian proposed an industrial load control strategy based on the characteristics of industrial loads, and the effect of industrial loads participating in DSM under different pricing modes is analyzed and compared [6].…”

Review of Trends and Targets of Complex Systems for Power System Optimization

“…Some papers propose an optimum load control and schedule system which controls many loads of various types located in various locations as one large aggregate load. Such systems are presented, for example, in [52][53][54]. When optimizing PS operation using the load control, technically, the easiest load-control method is to control large compact loads, because this type of control allows changing PS's total power consumption by hundreds of MW, even when controlling only a small number of loads.…”

Simulation Case Studies on Period Optimal Power Flow

“…For small variations in the equivalent load power, the frequency control hierarchy of power systems will track the frequency deviation and adjust the controllable power. For both primary and secondary frequency modulation, it is assumed that the active power adjustment from controllable power source c i P  (Trovato et al 2017) is a linear function of the grid frequency deviation f  , that is,…”