IEC 60034-3:2020 pdf free.Rotating electrical machines – Specific requirements for synchronous generators driven by steam turbines or combustion gas turbines and for synchronous compensators.
Suitable precautions shall be taken to prevent harmful flow of shaft current and to earth therotor shaft adequately. A turbine-generator shaft shall be earthed at a shaft position close tothe reference end of the generator. Shaft voltage spikes caused by static excitation withcontrolled rectifiers shall be kept down by suitable means to non-critical values.These spikescan cause damage, for example to the bearing Babbitt, by breaking through the bearing oil film.
Requirements for bearing insulation resistance to be measured during operation of thegenerator or compensator shall be agreed upon at the time of purchase.
4.11overspeed test
Rotors, i.e. main shaft and if applicable slip ring shaft or exciter shaft, shall each be testedcompletely assembled at 1,2 times rated speed for 2 min.
lf rotor fan blades are not assembled to avoid larger windage loss at overspeed test, this canbe acceptable when the mechanical strength is assured by traceability of the material whichwould be proven by mill test report and non-destructive test report for design requirements.
The purpose of the rotor over-speed test is verifying the mechanical integrity of the rotor.Thistest is not intended to indicate the in-service operating capability of the machine.The in-serviceover-speed withstand capability of the generatorlcompensator and the frequency with whichsuch an over-speed may be applied depends upon the design of the generator or is necessary to consider carefully any in-service over-speed conditions which could resultfrom sudden disconnection of full load for example.Any particular requirements shall be agreedupon.
4.12Critical speeds
Critical speeds shall not cause unsatisfactory operation of the combined generator-/turbine-shaft train within the speed-/frequency-range corresponding to lEC 60045-1 or agreed uponotherwise. This also applies to compensator rotors.
lf generator and turbine are purchased from different manufacturers,there shall be anagreement on which party is responsible for achieving the desired performance of the combinedturbinelgenerator shaft line including exchange of turbine and generator shaft data.
4.13 P-o capability diagram
For generators, the manufacturer shall supply a P-Q capability diagram indicating the limits ofoperation.The P-Q diagram shall be drawn for operation at rated conditions. A typical P-Qdiagram is shown in Figure 2; its boundaries are set by the following limitations:
curve A represents operation with constant rated field current and therefore withapproximately constant temperature rise of the field winding;
curve B represents constant rated stator current and consequently approximately constanttemperature rise of the stator winding.IEC 60034-3 pdf download.