Performance of industrial melting pots in the provision of dynamic frequency response in the Great Britain power system

Nikola Gargov,Meng Cheng,Jianzhong Wu,Stephen J Galsworthy,Yue Zhou,William H Hung

doi:10.1016/j.apenergy.2016.12.014

Nikola Gargov, Meng Cheng + Show 4 more

Open Access

https://doi.org/10.1016/j.apenergy.2016.12.014

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Abstract

As a result of the increasing integration of Renewable Energy Source (RES), maintenance of the balance between supply and demand in the power system is more challenging because of RES’s intermittency and uncontrollability. The smart control of demand is able to contribute to the balance by providing the grid frequency response. This paper uses the industrial Melting Pot (MP) loads as an example. A thermodynamic model depicting the physical characteristics of MPs was firstly developed based on field measurements carried out by Open Energi. A distributed control was applied to each MP which dynamically changes the aggregated power consumption of MPs in proportion to changes in grid frequency while maintaining the primary heating function of each MP. An aggregation of individual MP models equipped with the control was integrated with the Great Britain (GB) power system models. Case studies verified that the aggregated MPs are able to provide frequency response to the power system. The response from MPs is similar but faster than the conventional generators and therefore contributes to the reduction of carbon emissions by replacing the spinning reserve capacity of fossil-fuel generators. Through the reviews of the present balancing services in the GB power system, with the proposed frequency control strategy, the Firm Frequency Response service is most beneficial at present for demand aggregators to tender for. All studies have been conducted in partnership between Cardiff University, Open Energi London – Demand Aggregator, and National Grid – System Operator in GB to ensure the quality and compliance of results.

Highlights

The increasing integration of Renewable Energy Source (RES) will reduce the capacity of fossil-fuel generators and ⇑ Corresponding author.reduce the Green House Gas (GHG) emissions
When there is an increase in frequency, more Melting Pots (MPs) will be available to be switched On to respond to the frequency increase compared with the alternative case when there is a frequency drop, the MPs will be switched Off
To investigate the impact of location on the response provided by MPs, a case study was carried out using the master dynamic Great Britain (GB) power system model in National Grid which is at present used by the system operator for network studies

Summary

Introduction

The increasing integration of Renewable Energy Source (RES) will reduce the capacity of fossil-fuel generators and . The power consumption of the loads can be shifted in time as long as their temperature stays within the pre-set set-points These domestic loads usually have small power consumption (e.g. 4.5 kW for water heaters and 0.1 kW for refrigerators) and require an aggregation of great numbers of loads in order to provide a notable response in the context of the GB power system with a minimum demand of approx. The potential benefits of demand to participate in the balancing services based on the present operational practice of the GB power system were discussed and compared

Model of melting pot loads and validation

Thermodynamics in a melting pot

Definition of tON and tOFF of a Melting Pot

Simplified curve-fit model of a melting pot

Control of melting pots for frequency response

Case studies and discussions

Mps’ response following continuous normal frequency variations

Mps’ response following abnormal frequency incidents

Mps’ response from different locations

Expected MPs’ response under the May 2008 frequency incident

Conclusions