Hydro Power

An overview of the hydro turbine governor will be given. The idea of the governor was first treated

analytically by Clark Maxwell in the 19th century. Governor action was correctly seen as something

very important in the days when hydro plants were installed as the sole or the principal contributor to a

small power system. As large interconnected systems developed, the large number of loads and

generators obscured the action of the governor. Less interest was taken in how the governor should be

specified and adjusted for use in a large interconnected system. However, mysterious power flows

began to be seen in generation areas where the generation was predominantly hydro. This led to

governor setting policies, which are valid today. Now, we have the ability to build very large computer

models and to demonstrate the significance of the governor. In addition, it has been demonstrated that

the computer models may indicate that a system is robust, while real life experience shows that the

system has collapsed. This anomaly has been explained by inadequate representation of the hydro

turbine and its governor. It is now a requirement of the System Operator that hydro power plant

owners submit data that will allow realistic models to be developed for inclusion in system models.

This tutorial is intended to prepare engineers, as well as practitioners of other profiles and students

interested in the hydro power generation, to understand the operation of governor and to describe the

control system and the hydro turbine governor control parameters.

John Codrington received his B.Sc. (Hons) in Mechanical Engineering from University of Manchester,

England in 1964. He has been with Acres, and now Hatch Energy, for 43 years and has contributed to

many different projects. His most recent experience has been in hydroelectric engineering, much of

this being in Latin America and Iran. He made a major contribution to the conceptual work and was

responsible for the specifications for the Pelton turbines and the gates for the San Gaban hydroelectric

project, Peru. He contributed to a proposed high head Pelton station in Guatemala, making

recommendations to deal with hydraulic transients. He was more recently assigned overseas to work

on the 2000 MW Karun III project in Iran, where he was responsible for the design review of all

mechanical equipment including the Francis turbines, the governors, the gates in the high head arch

dam, and other equipment in the powerhouse. He participated in the shop testing of the governor,

where a feedforward algorithm requested in the specifications was coded in and successfully tested in

the course of the shop testing. He has participated in studies dealing with dynamic problems and

frequency regulation at a hydroelectic plant supplying a mining and smelting operation in Indonesia.

He has a strong background in analysis of transients in pumping installations and hydro plants.

He prepared a computer model to investigate the dynamic behaviour of the interconnected electrical

system following a proposed intertie between Kenya and Tanzania. This model was focussed on prime

mover control and investigated how the system and the proposed tie lines responded to load changes.

Mr. Codrington prepared technical specifications and participated in procurement of hydro turbine

governor systems for major projects such as Churchill Falls, Labrador, Akosombo in Ghana, and Karun

III in Iran. In each of these cases, special demands were made on the governor systems and special

features were specified.

He recently participated in studies for the Blue Lake project for the City of Sitka, where a preliminary

surge tank configuration was developed and estimates were made of the local power system frequency

response to load demand changes. A customized computer model was prepared to analyze the response

of the electrical system to demand changes.

Mr. Codrington is a registered Professional Engineer in the province of Ontario, and a Life Member of

the American Society of Mechanical Engineers (ASME).

Related Representative Publications

• "Hydroelectric Turbine Regulation Criteria", Presented at ASME Winter Annual Meeting,

Anaheim, California, Publication FED-Vol. 136, November 1992.

• "Computer Representation of Electrical System Interaction with a Hydraulic Turbine and

Penstock", Joint Power Generation Conference, St. Louis, Missouri, 1981. (Coauthor)

• "The Use of Impedance Concepts and Digital Modelling Techniques in the Simulation of

Pipeline Transients", Presented at the 2nd International Conference on Pressure Surges,

London, England, September 1976. (Coauthor)

answ2. Hydroelectric dams are temporary features. They will eventually fill up with gravel and silt from the river. This is very expensive to remove.

Otherwise the maintenance is things like removal of debris that may damage the turbines. The actual maintenance of turbines and generators is small - occasionally bearings need replacement and so on. Pretty minimal overall.

Hydroelectricicity is expensive to install, but the annual running costs are very small.