Sustainable Electrical Power Systems Engineering

This unit aims to help you understand the structure of electrical energy systems from the perspectives of a national grid, a distribution network, and an industrial/commercial facility. It introduces the components included within an electrical energy system, the models used to represent each component and the basic analytical techniques used to combine these component models into an electrical energy system. Models will include generators, power transformers, lines, cables, loads and power electronic devices; and analytical techniques will include per-unit, phasors and power flow. It also introduces an independent study of academic literature focusing on differences between national power systems and their methods of overcoming the challenges to reaching a sustainable system.

Structure of Electrical Energy Systems

• Transmission and Distribution
• Renewables, & Energy Storage

Basic Analytical Skills Associated with an Electrical Energy System

• Per-unit
• VA and V Phasors
• Real and Reactive Power
• 2-bus power flows
• Power quality and power factor
• Power vs Energy includes peak, average and reactive power

Components Associated with an Electrical Energy System

• Power Transformers
• Lines and Cable
• Synchronous Generators
• Load modelling
• Power Electronics, AC/DC converters and DC/AC inverters

The unit aims to impart knowledge and skills for mathematical modelling as well as the techniques for steady-state and dynamic analysis of electric power transmission networks. It introduces the techniques required to analyse the power flow and fault performance of systems ranging in size from local islanded power systems to pan-country grids.

It also introduces the techniques required to analyse and understand the performance of the power electronic systems that are increasingly important in modern power systems such as HVDC.

Faults in Power Systems

• Symmetrical fault calculations: Modelling of networks under fault; solution using basic circuit analysis; the concept of short-circuit level and its factors of influence; faults in large networks.
• Asymmetrical fault calculations: Synthesis and connections of sequence networks; solution of sequence networks by standard circuit analysis techniques; transformation back to the phase domain.

Analysis and Control of Large Networks

• Formulation of the power flow problem from first principles: Rectangular and polar forms; numbers of equations and variables; Bus classification (PQ, PV, slack); matrix-vector formulation.
• Solution techniques for the power flow problem: Newton-Raphson algorithms (basic principle in one dimension; extension to the multi-dimensional case; load flow feasibility, convergence and ill-conditioning; exploitation of PQ decoupling), DC power flow.
• Control of real and reactive power flows.
• Frequency regulation techniques in large power networks.

Analysis and Control of Power Electronics Systems

• Piece-wise-linear modelling and numerical techniques for time-domain solution; circuit simulation; statespace averaging, and small-signal linearization; transfer function models.
• Lumped parameter modelling of transient and steadystate mechanical and thermal systems; application of state-variable systems.

You will gain a clear understanding of the principles underpinning the design of the major items of power system plant. Studying this unit will help you to evaluate the design of the major items of power system plant through calculations that are paper-based, within spreadsheets and based on the use of commercial software packages. You will also gain knowledge of the way asset management techniques can be employed on a power system and study the electrical measurement techniques and condition diagnostic methods that are used in the type testing process and/or during production/commissioning/inspection.

Basic Principles
Key issues underpinning the design of power system equipment, high voltage failure mechanisms and fundamentals of heat transfer in power system equipment.

Design of Major Power System Plant Components

• Transformers (Transformer design and structure, volts per turn calculation, non-linear transient overvoltage distribution along a winding, thermal diagram, leakage reactance, tap changers, oil/cellulose insulation materials).
• Overhead Lines (Basic overhead line design, variation of air gap strength with voltage type, conductors/sag/tension, lightning protection, EM field environment), insulator design, thermal and current rating.
• Cables (Basic design, single core / three phase construction, XLPE & paper materials, electrical parameters, electric field / minimisation of electric field, thermal calculations including variation with voltage level, sheath bonding techniques).
• Switchgear (Types of switchgear, characteristics of an electric arc, high resistance interruption, low resistance interruption, TRV – single & double frequency, chopping overvoltages / pre- & re-strikes in vacuum).

Asset Management and Condition Monitoring

• The practical nature of managing asset of a large network in the context of testing/diagnostic methods, data collection and interpretation.
• Asset management in the context of a full life cycle management and linking asset management with risk/impact of failure of the components.

Substation and System Design

Earthing systems, insulation coordination and substation design.

This unit aims to introduce you to the fundamentals of power system operation and economics. The emphasis is placed on the need to balance the desire to operate and plan as economically as possible, with the need to maintain the security of the system. In order to do so in a market context, the unit also gives an understanding of the economic principles underlying the introduction of competition in the generation and retail of electricity as well as the opening of the transmission and distribution systems to third party access.

Introduction to Optimisation and Optimal Economic System Operation

• Introduction to power system economics: electricity as a commodity and trade-off between economical and secure supply.
• Introduction to nonlinear optimization concepts and Karush-Kuhn-Tucker (KKT) conditions.
• Introduction to economic dispatch, KKT solution, and interpretation of Lagrange multipliers.
• Introduction to unit commitment.

Electricity Markets and Power System Economics

• Foundations of microeconomics: Supply and demand; price elasticity; surplus; social welfare; market equilibrium; theory of the firm; fixed cost, marginal cost, average cost.
• Introduction to risk: Definition; price risk management and contracts; principles of portfolio design.
• Industry restructuring: Objectives; unbundling; market players; basic structures: pool, bilateral and mixed.
• Electricity marketplaces: Forward and spot (balancing) markets; power exchanges; generation scheduling; two-settlement system.
• Participation in electricity markets: producers, retailers, customers, hybrid participants.
• Network effects: Locational marginal pricing; transmission losses and constraints; transmission rights.

Concepts of Power System Security

• Supply and demand balance over different timeframes: ancillary services in a market environment and concept of (N-x) security.
• Optimal power flow and DC approximation.

Power System Investment

• Generation investment: Drivers for capacity expansion and retirement; risks.
• Transmission investment: Costing and pricing of transmission networks; value of transmission; need for regulation; approaches to transmission pricing.

Electrical power systems and the challenges facing them are rapidly changing. This unit explores the main concepts behind smart grids and low carbon networks, two prominent changes in power systems. It allows you to know, or calculate, the impact of some of these current and future changes. More so than other units the focus here is on environmental concerns as well as the technical and economic (the energy trilemma).

Distributed Low Carbon Technologies

• Introduction to distribution networks
• Distributed generation: impacts and challenges
• Electric vehicles: impacts and challenges
• Photovoltaic panels: impacts and challenges
• Other technologies: storage, smart appliances, etc.

Smart Grids

• Distributed generation and active network management
• Present and future challenges for T&D
• Introduction to smart grids
• Smart grids - transmission and distribution perspectives
• Demand side management

Sustainable Electricity Systems

• Towards low-carbon networks
• Introduction to low carbon thermal generation (nuclear, Carbon Capture and Storage, bio diesel, biomass)
• Renewable Energy: system-level integration challenges (operational reserves, impact on conventional generation, capacity credit)
• Emission models and indicators
• Introduction to multi-generation (cogeneration, micro CHP, waste heat recovery, tri-generation, heat storage, heat networks)
• Electrification of heating: introduction to electric heat pumps
• Decarbonisation of transport
• Contribution from demand side management to low carbon system operation

This unit aims to introduce you to basics of power system dynamics and quality of electricity supply issues and to discuss most widely used and recommended methodologies for enhancement of power system stability and mitigation techniques to overcome problems associated with quality of electricity supply.

Power System Dynamics

• The dynamic characteristics and control requirements of power systems are introduced. Consideration is given to the dynamic modelling
• of major power system components and controls including power system loads, excitation systems and governors.
• The modelling and control requirements will be discussed for small and large disturbances studies and voltage stability studies. Methodologies, tools and techniques for performing these types of studies will be introduced.
• The methodologies for enhancement of power system stability and tuning of power system controllers will be discussed.

Quality Of Supply

• Introduction to Quality of Supply: Essential terms and definitions, importance and relevance, types of studies. Voltage variations in power system over and under voltages voltage flicker and voltage transients.
• Voltage sags: definition, characteristics and causes, propagation and representation, consequences of voltage sags.
• Harmonics: Definition, propagation, sources and consequences and harmonic filter design.
• Assessment of financial losses due to power quality disturbances and recommended mitigation practise to solve quality of supply problems.

Reliability

• Introduction to Reliability: Essential parameters, indicators and functions for non-reparable and reparable systems. State-space representation,
• Markov’s model, network models: series-parallel connection, state enumeration, Monte Carlo simulation.
• Generation systems: basic methods, operating reserve, interconnected systems.
• Composite generation and transmission systems: enumeration technique and Monte Carlo simulation.
• Distribution systems: radial networks, analytical techniques.

This unit aims to introduce the classical and advanced operating principles and main features of various types of relays and protection schemes. It provides the knowledge necessary to understand how these relays and schemes are applied to the protection of plant and systems including transmission, distribution and industrial networks and rotating machines.
It describes the methods and instrumentation used for testing of protective devices and complex protective solutions involving a larger number of protective devices.

Finally, the unit introduces the principles of wide-area monitoring, protection and control, which are underpinned by the availability of high-speed information and communication technology in protection schemes.

Introduction to Protection Systems

The importance of protection to the reliability of industrial and commercial power networks, protection relay types, current/voltage transformers.

Conventional Protection Systems

Fuses, overcurrent protection, high/low impedance differential protection, busbar protection, transformer protection, distance protection schemes, protection of rotating machines, including motor and generator protection.

Advanced Protection Systems

The advantages and disadvantages of multi-functional numerical protection and control devices. Principles of protection of networks with distributed generators. Wide area monitoring, protection and control systems, aimed for the protection and control of integrated power systems. Communication technology used in protection of power systems and in substations.

This unit prepares you for individual or team-based research projects by introducing methods used in research and development. It aims to:

1. Prepare you for research project work through the practice of:

• Independent research/self-learning (literature review, ideation, creative problem solving),
• Project planning (scope, resource, timelines, risk),
• Writing reports.

2. Encourage exploration of professional responsibility in the wider context in which engineering operates (ethical, environmental, regulatory, managerial, and social contexts).

3. Apply technical engineering innovations to a commercial and business context (including presenting an overview of intellectual property).
Improve the effectiveness of team working, decision making, and presentations.

The dissertation should demonstrate an appropriate level of professional competence in the practical development of a suitable application that meets a perceived need, specification or the realisation of a research project.

Knowledge and understanding

• Describe and evaluate the methodology used.
• Demonstrate the application of the appropriate disciplinary skills.
• Describe and evaluate the solution and its theoretical and practical significance.

Intellectual skills

• Analyse a problem and the relevant literature or practical context.
• Design an appropriate solution.
• Appraise critically the project, indicating the rationale for the proposed solution, lessons learnt during the course of the project, and evaluation of the solution and methodology used.

Practical skills

• Use software, simulation and CAD tools as appropriate in the construction of the problem solution.
• Use programming and software tools relevant to the system operation.
• Use appropriate test and measurement equipment to acquire data related to the problem.
• Use hardware necessary to construct and integrate the system.
• Use software tools as appropriate to record and analyse data.

Transferable skills and personal qualities

• Demonstrate creativity and problem-solving skills.
• Demonstrate academic writing (including use of references), project management, risk analysis, project documentation.