Power Circuits and Transmission

Learning Outcomes

Knowledge and Understanding

Having successfully completed this module, you will be able to demonstrate knowledge and understanding of:

• Transmission line theory for high and low frequency applications, short, medium and long lines, and solving of transmission problems.
• Power flow in AC circuits, conservation of power and calculation of power in single and three-phase circuits.

Subject Specific Intellectual and Research Skills

Having successfully completed this module you will be able to:

• Apply concepts of network topology to problems.
• Apply sequence network representation to overhead lines and buried cables.

Subject Specific Practical Skills

Having successfully completed this module you will be able to:

• Perform laboratory measurements on three-phase circuits and establish transmission line parameters.
• Apply basic synthesis techniques for realising impedances.
• Model transmission lines of varying length, apply different solution methods to general electrical network problems.

Transferable and Generic Skills

Having successfully completed this module you will be able to:

• Undertake laboratory experiments as part of a small team, record, analyse and report on laboratory results.
• Perform analytical and numerical modelling at appropriate detail for different applications

Network Topology:

• Definitions: trees, links, loops, cuts etc., conversion of circuits to branches and loops, etc., and the possible variations for any given circuit;
• expansion of Kirchhoffs laws in cuts and loops;
• formation of current branch matrices and the relationships I = C.i and V = A.B;
• determination of admittance and impedance matrices;
• methods of solutions (including revision of matrix algebra).

State-space circuit models:

• Examples of derivation;
• solution of state equations by Laplace transform methods;
• solution of simple circuit network problems.
• Sinusoidal steady-state from the state-space point of view.

Three-phase:

• Unbalanced mesh and four-wire star circuits;
• unbalanced three-wire star circuits;
• solution by Millman's theorem, star-delta transform and graphical methods;
• symmetrical components and use in solving unbalanced systems;
• positive, negative and zero sequence networks;
• use of two wattmeter method on balanced and unbalanced systems for kW and kVAr measurement.

Two Port Networks:

• ABCD parameters;
• Simple transmission networks:
• series impedance, shunt admittance, half T and half Pi network, T and Pi networks, ideal and actual transformer, pure mutual inductance;
• ABCD relation for a passive network;
• Output in terms of input;
• Evaluation of ABCD parameters from short circuit and open circuit tests;
• ABCD parameters for symmetrical lattice;
• Networks in parallel;
• The loaded two port network;
• image impedances and matching a resistive load to a generator;
• Image impedance in terms of Zsc and Zoc; Insertion loss ratio;
• Propagation coefficient;
• Per-unit system.

Transmission line theory as applied to power transmission:

• Definition of short, medium and long lines and their simulation with discrete elements;
• solution of T and Pi networks, with appropriate phasor diagrams, ABCD constants.
• Lossy and lossless line models.
• Telegraphist's equations, relation to the wave equation.
• Voltage standing waves on a lossless line;
• Standing waves of current on a lossless line.
• Voltage surges;
• Reflection coefficient;
• Pulses on transmission lines, signal transfer.
• Impedance, Admittance and Smith Chart.
• Stub matching and stub filters;
• Voltage surges;
• Reflection coefficient;
• Pulses on transmission lines, signal transfer.
• Distortion free conditions.
• Special cases: quarter and half wave length lines, matched impedances, short and open terminations.

Electromagnetic background.

• Field analysis of transmission lines;
• Telegraphers Equation derived from Field Analysis for the coaxial line.

Rigorous solution for uniformly distributed constants (in both the time and frequency domains);

• reflected and incident values, propagation constant, attenuation and phase constants, surge/characteristic impedance;
• algebraic and hyperbolic equations with ABCD comparison of the latter with Pi networks.
• Examples: Coaxial cable, stripline, microstrip; balanced lines: twisted pairs.

The content of this module is delivered through lectures, module website, directed reading and tutorials.

Students work on their understanding through a combination of independent study, preparation for timetabled activities, tutorials and problem classes, along with formative assessments in the form of coursework assignments.

Students work on their practical skills, professional skills and technical understanding in laboratories.

Summative

This is how we’ll formally assess what you have learned in this module.

Referral

This is how we’ll assess you if you don’t meet the criteria to pass this module.

Repeat

An internal repeat is where you take all of your modules again, including any you passed. An external repeat is where you only re-take the modules you failed.