Demand side participation for frequency containment in the web of cells architecture (original) (raw)
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2015 International Symposium on Smart Electric Distribution Systems and Technologies (EDST)
The role of demand side management in providing ancillary services to the network is an active topic of research. However, their implementation is limited due to lack of practical demonstrations and tests that can rigorously quantify their ability to support the grid's integrity. In this paper, provision of time critical frequency control ancillary service is demonstrated by means of integrating PowerMatcher, a well discussed demand side management mechanism in literature, with real-time power hardware. The co-simulation platform enables testing of demand side management techniques to provide ancillary services.
A hierarchical framework for demand-side frequency control
2014 American Control Conference, 2014
This paper aims to develop a hierarchical framework for demand-side frequency control. The framework involves two decision layers. The top layer determines a control gain for the aggregated load response on each bus using robust decentralized control theory. The second layer involves a large number of devices, which switch probabilistically during contingencies so that the aggregated power change matches the desired droop amount according to the control gains determined in the top layer. The proposed framework is based on the classical nonlinear multi-machine power system model, and can deal with time-varying system operating conditions while respecting the physical constraints of individual devices. Realistic simulation results based on a 68-bus system are provided to demonstrate the effectiveness of the proposed strategy.
A Decentralized Strategy for Frequency-based Load as Regulation
IOP Conference Series: Materials Science and Engineering, 2019
In order to keep frequency stable after UHV DC block fault, demand side resources are needed. Among these, frequency-based load can automatically monitor the frequency change without affecting the user’s power consumption experience and can quickly adjust the operating parameters to reduce its own power consumption. Thus, frequency-based load can play a role similar to the primary frequency regulation. In this paper, several physical models of typical frequency-based loads were established and the frequency regulation characteristics are analyzed. Based on this, a decentralized strategy of frequency-based load was proposed. The simulation results show that the grouping decentralized strategy can effectively avoid the “over-control” or “under-control” phenomenon, which helps to quickly maintain the power balance and frequency stability of the grid.
Smart Demand for Frequency Regulation: Experimental Results
IEEE Transactions on Smart Grid, 2013
As renewable energy sources increase their penetration, the traditional providers of frequency regulation service, fossil fueled thermal power plants, will be displaced, motivating the search for novel providers such as demandside resources. This paper presents the results of field experiments using demand as a frequency controlled reserve (DFCR) on appliances with programmable thermostats. The experiments conducted showed the response of a population of thermostatically controlled loads acting as normal reserves and disturbance reserves as defined by the Nordic Grid Codes [1]. In addition, industrial pump loads and relay-controlled loads were tested as DFCR. The tests show that a population of refrigerators was able to deliver frequency reserves approximately equal to their average power consumption. Electric space heaters were able to provide frequency reserves of over 90% their maximum power consumption in certain weather conditions.
Decentralized Demand-Side Contribution to Primary Frequency Control
IEEE Transactions on Power Systems, 2011
Frequency in large power systems is usually controlled by adjusting the production of generating units in response to changes in the load. As the amount of intermittent renewable generation increases and the proportion of flexible conventional generating units decreases, a contribution from the demand side to primary frequency control becomes technically and economically desirable. One of the reasons why this has not been done was the perceived difficulties in dealing with many small loads rather than a limited number of generating units. In particular, the cost and complexity associated with two-way communications between many loads and the control center appeared to be insurmountable obstacles. This paper argues that this two-way communication is not essential and that the demand can respond to the frequency error in a manner similar to the generators. Simulation results show that, using this approach, the demand side can make a significant and reliable contribution to primary frequency response while preserving the benefits that consumers derive from their supply of electric energy.
International Journal of Emerging Electric Power Systems, 2017
Nowadays the contribution of smart load technologies to power system frequency regulation is spurred due to the increasing penetration of renewable energy resources. This paper presents a comprehensive and up-todate critical review on different decentralized load control strategies. This includes a joint literature-as well as simulation-based investigation in order to scrutinize different decentralized frequency-based load modulation strategies through organizing a taxonomy table and performing different simulation scenarios. Furthermore, the effectiveness of different gain tuning procedures in each control action are scrutinized and compared in terms of frequency nadir and steady state error. The detailed simulation is performed using SimPowerSystem (SPS) toolbox, in phasor mode, on IEEE 39-bus New England test system.
Real-Time Central Demand Response for Primary Frequency Regulation in Microgrids
Providing ancillary services for future smart microgrid can be a challenging task because of lack of conventional automatic generation control (AGC) and spinning reserves, and expensive storage devices. In addition, strong motivation to increase the penetration of renewable energy in power systems, particularly at the distribution level, introduces new challenges for frequency and voltage regulation. Thus, increased attention has been focused on demand response (DR), especially in the smart grid environment, where two-way communication and customer participation are part of. This paper presents a comprehensive central DR algorithm for frequency regulation, while minimizing the amount of manipulated load, in a smart microgrid. Simulation studies have been carried out on an IEEE 13-bus standard distribution system operating as a microgrid with and without variable wind generation. Simulation results show that the proposed comprehensive DR control strategy provides frequency (and consequently voltage) regulation as well as minimizing the amount of manipulated responsive loads in the absence/presence of wind power generation.
Effects of dynamic-demand-control appliances on the power grid frequency
Power grid frequency control is a demanding task requiring expensive idle power plants to adapt the supply to the fluctuating demand. An alternative approach is controlling the demand side in such a way that certain appliances modify their operation to adapt to the power availability. This is especially important to achieve a high penetration of renewable energy sources. A number of methods to manage the demand side have been proposed. In this work we focus on dynamic demand control (DDC), where smart appliances can delay their switchings depending on the frequency of the system. We introduce a simple model to study the effects of DDC on the frequency of the power grid. The model includes the power plant equations, a stochastic model for the demand that reproduces, adjusting a single parameter, the statistical properties of frequency fluctuations measured experimentally, and a generic DDC protocol. We find that DDC can reduce small and medium-size fluctuations but it can also increase the probability of observing large frequency peaks due to the necessity of recovering pending task. We also conclude that a deployment of DDC around 30-40% already allows a significant reduction of the fluctuations while keeping the number of pending tasks low.
Primary frequency regulation with load-side participation: stability and optimality
2016
We present a method to design distributed generation and demand control schemes for primary frequency regulation in power networks that guarantee asymptotic stability and ensure fairness of allocation. We impose a passivity condition on net power supply variables and provide explicit steady state conditions on a general class of generation and demand control dynamics that ensure convergence of solutions to equilibria that solve an appropriately constructed network optimization problem. We also show that the inclusion of controllable demand results in a drop in steady state frequency deviations. We discuss how various classes of dynamics used in recent studies fit within our framework and show that this allows for less conservative stability and optimality conditions. We illustrate our results with simulations on the IEEE 68 bus system and observe that both static and dynamic demand response schemes that fit within our framework offer improved transient and steady state behavior comp...
Journal of International Council on Electrical Engineering, 2012
This paper presents the effectiveness evaluation approach of demand side management (dema nd control) for frequency regulation in regional power networks (so called Cluster-oriented networks). The analytical model of the frequency fluctuation for a three-cluster interconnected network model was developed with MATLAB/SIMULINK. The control method is similar to the conventional TBC (Tie Line Bias Control) widely used in power grids. In order to maintain the quality of frequency, Battery Energy Storage Systems (BESS) and controllable loads such as heat pumps installed in the customer side will play an effective role in clusters. By the results of conducted simulations, it shows that the proposed new frequency regulation scheme by utilizing controllable loads such as battery charges and heat pumps retains effectiveness to suppress frequency deviation when a large amount of natural renewable energy is installed in the regional cluster-oriented networks.