Zeyad Assi Obaid

Modelling of a population of Heat Pumps as a Source of load in the Great Britain power system

The developments of large-scale renewable energy cause significant challenges for the operation of power system. Demand Side Response (DSR) based Thermostatically Controlled Loads (TCLs) may offer a broad range of potential benefits on system operation and reliability. This paper investigates the modelling of aggregated small loads, such as Heat Pump (HP). The simplified thermodynamic model of a residential single Air Source Heat Pump (ASHP) was developed and simulated using Matlab. A decentralized temperature control algorithm was used to control the ON/OFF cycle of the heat pump offering comfort to the customer. The behaviour of a population of controlled heat pumps was examined. Seven case studies were conducted to identify a suitable number of individual heat pump models that can be used to represent the total number of heat pumps in the UK according to the National Grid 2030 medium uptake scenario. Simulation results showed that an aggregation model of 5,000 individual heat pumps is suitable to represent the total number of heat pumps in the GB power system.

Small Microgrid stability and performance analysis in isolated island

A generalized model of a Microgrid in an island mode is proposed for assessing the system power and frequency performances. This Microgrid (MG) includes a diesel backup generator along with a number of Distributed Energy Resources (DES): Wind Turbine Generator (WTG), Photovoltaic System (PV), Fly- Wheel Energy Storage system (FESS), and Battery Energy Storage System (BESS). Controlling the frequency deviation is posing a great challenge in stand-alone mode due to the mismatch between load demand and generation. Five different study cases were modelled in Matlab to investigate the performance and stability of the power system. Furthermore, two PD Fuzzy logic control plus Integral (PDFLC+I) act as supplementary controller were incorporated locally with diesel and storage elements in order to improve the robustness and safety of the system. Fuzzy rule and integral parameters were chosen to achieve fast response and small power and frequency deviation throughout step change in load profile. Classical PID controller was introduced for comparison purposes. The potential of using responsive charging electric vehicles (EVs) under three scenarios as a form of primary response was investigated. Simulation results showed that the decentralized controller eliminates the fluctuation effect of the wind turbine and stabilizes the system frequency. EVs can play important role in system primary frequency response.

Potential of a population of domestic heat pumps to provide balancing service

This paper investigates the model of aggregated heat pumps as a source of the flexible load in Great Britain. A thermal model of a domestic heat pump was presented. A decentralised temperature control algorithm was proposed to control the building temperature, and heat pump’s ON and OFF cycles. Seven case studies were used to identify the suitable number of individual heat pump models that can be aggregated to accurately represent the projected number of heat pumps connected to the 2030 GB’s power system. The simulation results revealed that an aggregated model of 5,000 individual heat pumps was accurately representing the entire number of heat pumps in the Great Britain power system. Also, the power consumption of a group of heat pumps was examined in response to the grid frequency. Simulation results showed that the power consumption of aggregated heat pumps was successfully controlled in response to a frequency change. The controlled heat pumps reduced the dependency on the frequency service obtained by expensive peaking generators.

Analysis of the Great Britain's power system with Electric Vehicles and Storage Systems

This paper presents an analysis of the simplified model of the Great Britain (GB) power system for 2030 projections. Electric Vehicles (EVs), Battery Energy Storage System (BESS), and Fly-Wheel Energy Storage System (FESS) are connected in the primary frequency control loop. PD -like Fuzzy Logic controller (PDFLC) is used as a secondary frequency control as well as the classical PID controller for the comparison of its performance. Seven different study cases with two modeling scenarios are used to (i) investigate the behavior of the GB power system for both primary and secondary frequency loops and (ii) the effect of the EV, FESS and BESS on the system power generation and frequency deviation. It was found that both types of storage systems increase the error and deviation of power and frequency especially when they were used together without Droop control due to the extra amount of power added to the system. EVs decrease the systems deviation, however, the limit of frequency with EVs is still above the acceptable UK limits. PDFLC is superior to the classical PID in reducing the frequency deviation and settling time which offers high stabilities and control performances in regulating the frequency.