In keeping with developments in turbine technology, the International Electrotechnical Commission has revised its key standard for model acceptance tests. Hans Teichmann reports

Founded in 1906, the international-electrotechnical-commission (IEC) is the world organisation which prepares and publishes international standards for all electrical, electronic and related technologies.

Comprising more than 50 participating countries, the Commission’s standards work is carried out by some 200 technical committees and subcommittees, and about 700 working groups. The technical committees prepare technical documents on specific subjects within their respective scopes, which are then submitted to the full member national committees for voting with a view to their approval as international standards.

In all, some 10,000 individuals throughout the world participate in IEC’s technical work.

Hydraulic machines

Hydraulic machines are standardised by technical committee IEC/TC4 (see table below right). Established in 1911, TC4 prepares international standards and reports for hydraulic rotating machinery and equipment associated with hydro power development. Developments in turbine technology have been rapid, and have prompted IEC/TC4 to update the IEC 60193 publication, which is the key standard in model acceptance tests for hydraulic turbines, storage pumps and pump turbines.

The second edition of IEC 60193 incorporates all essential technological and scientific changes of the last three decades and combines the first edition (1965) and its amendments, IEC 60497 (1976) and IEC 60995 (1991). The new edition is available in French and English.

New standard

The revised standard applies to laboratory models of any type of impulse or reaction hydraulic turbine, storage pump or pump turbine. It is also applicable to prototype machines with a unit power greater than 5MW or with a reference diameter greater than 3m. However, it may also be used for machines with smaller power and size capacities by agreement between the purchaser or supplier.

The standard is a sophisticated but practical tool for specifying, planning and constructing successful model tests. It is a key factor for achieving a machine which is well suited for the specific needs of a particular hydro power plant.

This standard may also be used for comparative tests, as well as research and development work.

The main objectives of the standard are to:

•Define the terms and quantities used.

•Specify the methods for testing and measuring the quantities involved in order to ascertain the hydraulic performance of the model.

•Specify the methods for calculating results and comparing with guarantees.

•Determine whether the guarantees which fall within the scope of the standard have been fulfilled.

•Define the extent, content and structure of the final report.

The most important feature of the second edition of IEC 60193 is that it looks at the arrangement for model acceptance tests which are performed on hydraulic turbines, storage pumps and pump turbines. Areas which are covered include:

•The rules for conducting tests.

•Contract discussions between the power plant owner, machine manufacturer and the consulting engineer.

•Measures to be taken if any phase of the test is disputed.

The additional information needed for prototype design and operation (a new subject) was introduced in clause 4.

The end-users of the standard are equipment manufacturers, power plant owners, consulting engineers and specialised laboratories.

Structure of the IEC 60193 second edition

1 General rules.
2 Execution of tests.
3 Main hydraulic performances – methods of measurements and results.
4 Additional performance data – methods of measurements and results.
Dimensionless terms.
Physical properties, data.
Derivation of the equation for the specific hydraulic energy of a machine.
Influence of the density of water on measurement and calibration.
Summarised test and calculation procedure.
Scale-up of the hydraulic efficiency of reaction machine.
Computation of the prototype runaway characteristics taking into account friction and windage losses of the unit.
Examples of determination of the best smooth curve: method of separate segments.
Examples of analysis of sources of error and uncertainty evaluation.
Efficiency scale-up for Pelton turbines.
Analysis of random uncertainties for a test at constant operating conditions.
Calculation of plant Thoma number.
Detailed flux diagram of specific hydraulic energy, flow and power.

IEC/TC 4: Hydraulic turbines

The committee maintains technical liaisons with several international organisations:
– ISO/TC 30, Measurement of fluid flow in closed conduits
– ISO/TC 108, Mechanical vibrations and shock
– ISO/TC 113, Hydrometric determination
– ISO/TC 115, Pumps
– CIGRE International Conference on Large High Voltage Electric Systems
These organisations are informed of the ongoing projects and may submit comments.
P-members: IEC/TC 4 has 18 participating countries (P-members) and 16 observer countries. P-members are Austria, Canada, China, Czech Republic, Egypt, France, Germany, Indonesia, Italy, Japan, Norway, Russian Federation, Spain, Sweden, Switzerland, UK, US and Yugoslavia.
Working groups: at present, technical work is carried out by several working groups. These include:
– WG 5 Vibration
– WG 14 Speed regulating systems
– WG 18 Scale effects
The working group on model acceptance was disbanded when its task was completed.