Page 556 - Industrial Power Engineering and Applications Handbook

161530 Industrial Power Engineering and Applications Handbook
Similarly, consider triangles FIF& and Fi F26i when = 744 kW
and FOB2 = 256 kW
Conclusion
1000 - y
or 1 A slight variation in the drooping characteristics causes a
2 600 variation in the load sharing.
or (a- 1) 600 = 2 x 1000-2y (2) 2 A machine that has a higher droop (G2 in the above case)
will share a larger load than the one that has a lower
From equations (1) and (2) droop.
1400a - 600 = 2 x 1000 3 The higher the droop, the higher will be the load variation.
4 When there is a difference in the full-load speeds the load
.. a=- 2600 sharing during a parallel operation will not be equal and
1400 the generators will operate underutilized.
= 1.86 HZ
Hence the significance of employing identical machines, when
and frequency of operation = 52 - 1.86 required to run in parallel to achieve the optimum utilization
= 50.14 HZ of their capacities.
To determine the fault level of the system when two or
and Y= 800 x 1.86 more machines are operating in parallel refer to Section
2 13.4.1 (5).
Relevant Standards

IEC Title IS BS
60034-1/1996 Rotating electrical machines 4722/1992, BS EN 60034-1/1995
Rating and performance 325/1996
60034-3/1988 Rotating electrical machines - BS EN 60034-3/1996
Specific requirements for turbine type synchronous
machines
- Specification for voltage regulation and parallel - BS 4999-140/1987
operation of a.c. synchronous generators

Relevant US Standards ANSI/NEMA and IEEE
ANSI/IEEE Recommended practice for emergency and standby
446/1995 power systems for industrial and commercial applications.
(IEEE Orange Book)
ANSUEEE Guide for generator ground protection
C37.101/1993
ANSI Synchronous machines
C50.10/1990
ANSVIEEE Test procedures for synchronous machines. acceptance and
115-1/1995 performance testing
NEMAMG- Motor and generators ratings, construction, testing and
111993 performance
NEMAIMG- Safety standards (enclosures) for construction and guide for
2/1989 selection, installation and use of rotating machines

Notes
1 In the tables of relevant Standards in this book while the latest editions of the standards are provided, it is possible that revised editions
have become available. With the advances of technology andor its application, the updating of standards is a continuous process by
different standards organizations. It is therefore advisable that for more authentic references, rcaders should consult the relevant
organizations for the latest version of a standard.
2 Some of the BS or IS standards mentioned against IEC may not be identical.
3 The year noted against each standard may also refer to the year of its last amendment and not necessarily the year of publication.