0
Research Papers: Gas Turbines: Turbomachinery

Coordinated Control of Gas and Steam Turbines for Efficient Fast Start-Up of Combined Cycle Power Plants

[+] Author and Article Information
Yasuhiro Yoshida

Research and Development Group,
Hitachi, Ltd.,
7-2-1 Omika-Cho,
Hitachi 319-1221, Ibaraki, Japan
e-mail: yasuhiro.yoshida.xb@hitachi.com

Kazunori Yamanaka

Turbine Products Headquarters Division,
Mitsubishi Hitachi Power Systems, Ltd.,
3-1-1 Saiwai-Cho,
Hitachi 317-0073, Ibaraki, Japan
e-mail: kazunori1_yamanaka@mhps.com

Atsushi Yamashita

Turbine Products Headquarters Division,
Mitsubishi Hitachi Power Systems, Ltd.,
3-1-1 Saiwai-Cho,
Hitachi 317-0073, Ibaraki, Japan
e-mail: atsushi1_yamashita@mhps.com

Norihiro Iyanaga

Turbine Products Headquarters Division,
Mitsubishi Hitachi Power Systems, Ltd.,
3-1-1 Saiwai-Cho,
Hitachi 317-0073, Ibaraki, Japan
e-mail: norihiro_iyanaga@mhps.com

Takuya Yoshida

Research and Development Group,
Hitachi, Ltd.,
7-2-1 Omika-Cho,
Hitachi 319-1221, Ibaraki, Japan
e-mail: takuya.yoshida.ru@hitachi.com

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 10, 2015; final manuscript received June 26, 2016; published online September 13, 2016. Assoc. Editor: Rakesh K. Bhargava.

J. Eng. Gas Turbines Power 139(2), 022601 (Sep 13, 2016) (9 pages) Paper No: GTP-15-1246; doi: 10.1115/1.4034313 History: Received July 10, 2015; Revised June 26, 2016

In the fast start-up for combined cycle power plants (CCPP), the thermal stresses of the steam turbine rotor are generally controlled by the steam temperatures or flow rates by using gas turbines (GTs), steam turbines, and desuperheaters to avoid exceeding the thermal stress limits. However, this thermal stress sensitivity to steam temperatures and flow rates depends on the start-up sequence due to the relatively large time constants of the heat transfer response in the plant components. In this paper, a coordinated control method of gas turbines and steam turbine is proposed for thermal stress control, which takes into account the large time constants of the heat transfer response. The start-up processes are simulated in order to assess the effect of the coordinated control method. The simulation results of the plant start-ups after several different cool-down times show that the thermal stresses are stably controlled without exceeding the limits. In addition, the steam turbine start-up times are reduced by 22–28% compared with those of the cases where only steam turbine control is applied.

FIGURES IN THIS ARTICLE
<>
Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Start-up sequence for a traditional control method of the GTs and the ST. GT start-up curves are shown for the first GT. The second GT is omitted for simplification. The GT speed and load are controlled by adjusting the gas control valves (GCVs). The ST speed and load are controlled by adjusting the steam control valves (SCVs).

Grahic Jump Location
Fig. 2

Start-up sequence for the coordinated control method of the GTs and the ST. GT start-up curves are shown for the first GT. The second GT is omitted for simplification. The GT speed and load are controlled by adjusting the gas control valves (GCVs). The ST speed and load are controlled by adjusting the steam control valves (SCVs).

Grahic Jump Location
Fig. 3

Block diagram for the coordinated control method of GTs and the ST

Grahic Jump Location
Fig. 4

The schematic of CCPP for simulation

Grahic Jump Location
Fig. 5

Simulation results of thermal stresses for restart after different start-up conditions. Vertical axis is normalized by the maximum thermal stress value of the start-up process after the 180-h cool-down.

Grahic Jump Location
Fig. 6

Comparison of start-up process between the coordinated control and ST control for restarts after the 180-h cool-down

Grahic Jump Location
Fig. 7

ST start-up time by the coordinated control method, where the vertical axis is normalized by the start-up time for the 180-h cool-down

Grahic Jump Location
Fig. 8

The functional relation of GT load and steady-state steam temperature at HRSG outlet

Grahic Jump Location
Fig. 9

Calculation method of operating value for GT load by using the predicted values of the ST rotor thermal stress

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In