The performance of a power system depends on the nature and profile of the connected load.
For heavy or light loads, the voltage profile of the transmission and distribution lines is hugely affected. In many practical cases, the power system is more efficient with the use of compensators that can be connected in series or in shunt with the lines; its location in the power grid and type are topics of research projects. The aim of this coursework is to build the understanding of the need and impacts of compensation techniques within a focussed part of a power transmission system.
A 275-kV transmission line (TL) is to be studied with regard to power flow and compensation. The line may be assumed to be fed from an ‘infinite’ generator (the Grid) and terminated with a lumped load with fixed real and reactive power.
The following system data applies.
2000 MVA, 50-Hz, 275-kV
Infinite Generator (Grid):
275-kV, 50-Hz, 3-ph, 100,000 MVA Fault level, X/R ratio =10, Voltage set at 1.0 p.u.
275-kV, 50-Hz, 100,000 MVA Fault level, voltage tolerance ±10%.
275-kV, 3-ph, 50-Hz, variable TL length in km, R = 8.15 m? / km, L = 0.52 mH / km,
C= 0.008 µF / km
Create and run load flow analysis of a model of the above system in ERACS (pay extra attention to parameters to be considered). Outline any assumptions made in representing the system, then;
a. Describe Ferranti phenomenon and verify it for a long transmission line of length of your own choice, closely observe the load-end voltage when the line is not loaded or lightly loaded
b. Study the impacts of lagging power factor loads (of different power factors and load magnitudes) connected to a long-line on both the line efficiency and voltage regulation.
c. Study the impacts of leading power factor loads (of different power factor and load magnitudes) connected to the same long-line studied in Section (b) above, on both the line efficiency and voltage regulation.
d. Based on the results obtained, show your understanding about the differences between lagging and leading power factor loads simulated in (b) and (c) above.
I. For a long transmission line of your choice (but different from Stage 1), study the impact of the shunt compensation that is installed nearby the load (of your choice). Prove that using shunt reactors improves the voltage profile with light loading; however, shunt capacitors will improve the voltage profile when the line
is heavily loaded. You need to present the test system parameters and the complete set of data that support your claim.
II. For the same long line chosen in part (I) above, with heavy load, examine the capacitive shunt compensation when it is installed at (25%, 50% and 75%) of the transmission line length. Critically comment on the impacts of the shunt compensation location.
III. Use the knowledge of series compensation functionality to study the impact of capacitive series compensation of 10% - 20% (choose your own value within this range) on the transmission system performance, assume the line loading and show clearly your series compensation capacitance value.
Blackout is a serious event that all electrical grid operators try to avoid. Hence they install monitoring and controlling equipment to identify causes as early as possible and provide protective/preventive solutions.
I. Examine the literatures to find a blackout event that occurred anywhere in the globe, identify its impacts, what was the main cause(s) of the event. Critically discuss the solution(s) that has been presented to prevent similar occurrence in the future.
II. Discuss in details the pros and cons of using PMUs in enhancing the electrical power grid stability.
III. Demand response is a technique that is currently used to manage the grid load during contingencies, explain how does it work and its impact on electricity price.
Marks will be awarded for the presentation of the assessment. You should submit a structured report presenting the outcome of each of the tasks listed above. Appropriate referencing should be employed and diagrams must be clearly annotated. You may include appendices for figures, data, etc. The report should be structured in a
professional manner following best practice of academic writing.
The generic marking criteria published with the module will apply and marks will be allocated to each of the tasks as outlined above. This work will worth 40% of the module mark.
Generic feedback will be provided shortly after submission. Within 2-3 weeks of the submission you will receive written feedback on your submission.