The Rockport plant-analysis of temporary fast turbine valving tests

Abstract

A series of temporary fast turbine v a l v i m) field tests were carried out on AEP's Rockport 1300 MW unit. These four tests at various unit loading levels verified the functional aspects of the TFTV scheme-including the control and intercept valve stroke characteristics and the rapid reduction of mechanical driving power. This paper presents an analysis of the mechanical and electrical performance characteristics of the Rockport unit during TFTV. A comparison of the test measurements with digital simulation results is also provided to validate the simulation tools and models commonly used in system dynamics studies.

Feasibility of different corrective control options for the improvement of transient stability

“…The curves in Fig. 3 are typical curves obtained based on information taken from [7][8][9][11][12][13][14] which present different curves for various FV schemes, according to manufacturer information, design characteristics and field tests. All the characteristics presented in the cited references are similar and the curves in Fig.…”

“…However, it is not recommended because the sudden drop in pressure that occurs when both valves are closing could affect the boiler and control systems negatively [8]. It is also observed that even though the valves could take around up to 6 s to completely open again, P m reacts faster and goes back to the initial value in less time, approximately 2-3 s, as shown in [7,[11][12][13][14] where the P m output versus time curve characteristics are presented, for different turbines in a FV scheme. Initial research on FV considered feasible its application in fossil-fired and nuclear units.…”

“…Initial research on FV considered feasible its application in fossil-fired and nuclear units. For fossil-fired units, actual test data is found in [8,[11][12][13][14]. Even in the cases when both IV and CV are used, the output power is reduced only to around 30% of the initial value in a total time that is usually about 1 to 1.3 s. The power output goes back to the initial value 2 to 2.5 s afterwards.…”

“…Several corrective control methods for TSI exist, such as connection of braking resistors [1][2][3][4][5][6], fast valving schemes in thermal generators [7][8][9][10][11][12][13][14][15], switched series capacitors [16], switched shunt capacitors [17], FACTS devices [18], control of HVDC links [19], islanding schemes [19], and generator and load shedding [19]. Previous work reported in the literature studied each method independently focusing mainly in the modelling and in the control of the insertion-removal of the specific devices to optimize the impact on TSI; some existing comparative studies [18] analyzed similar Corrective Measures (CMs) based on FACTS devices.…”

Field experience with momentary fast turbine valving and other special stability controls employed at AEP's Rockport plant

“…on the AEP System, extensive hfFW testing was performd on the first Rockport unit before this unit came in service in December 1984 [4]. The testing included evaluation of valve strokes, generator electrical quantities and unit thermal characteristics, as a result of fast valving operations with the unit at various load levels.…”