June 26—30, In many parts of the world, the impact of renewable energy, especially from intermittent sources as wind and solar is continuously increasing. In Germany, the share of renewable energy in electricity production is believed to increase from In order to operate an electrical system and control the mains frequency, the power supply must match the consumption at any time. Ancillary services like primary and secondary control are used to balance the system on a time-scale of several seconds up to 15 minutes.
Those control reserves are usually provided by thermal power plants.
Particularly in times of high shares of fluctuating renewable feed-in, thermal power plants are turned off or operated at minimum load to avoid electricity production at low electricity prices. However, an amount of about MW of fast responding primary control need to be provided in the European network of transmission system operators for electricity grid to maintain stable operation even in case of two simultaneous large unit outages. This requirement leads to situations, where thermal power plants are operated in minimum load below their marginal cost to provide control reserves even if there is a surplus of energy in the grid.
Operation in low load while at the same time providing control reserves leads to new challenges.
As the relation between energy production and the thermal storage capacities provided by the metal and fluid mass in the boiler is decreasing with the load, the ability of responding to control demands is naturally slowed down. Dynamic simulation of the thermodynamic power plant process turned out to be an efficient method to investigate such operational modes. Using comprehensive process models coupled with a control system model, equipment adaptions or control system updates can be evaluated in order to provide faster responses.
By increasing the specific amount of ancillary services per unit, the number of units necessary to provide the total amount of primary and secondary control could be reduced in situations with energy surplus. Sign In or Create an Account. Sign In. Advanced Search. Proceeding Navigation. Close mobile search navigation.
Thermal Power Plant Simulation and Control (IEE Power and Energy Series)
Previous Paper Next Paper. Article Navigation. University of Rostock, Rostock, Germany. This Site. Google Scholar. The simulation results are presented and analyzed in the following subsections. While the steam extraction point is set at the inlet of the IPTB, the relatively high temperature steam will pass a series of heat exchangers to store the thermal energy contained in the steam. The amount of steam extraction is controlled by the valve openings. Dynamic responses of mass flow rate in TES and output power: a mass flow rate and b output power.
After the charging process, the steam will flow into the condenser mixing together with the LPTB outlet steam. The study reported in this section is to investigate whether the thermal storage can be controlled in order to regulate the temperature and pressure of the exhaust steam at the outlet of the TES. Dynamic responses of mass flow rate in TES and output power: a mass flow rate; b output power. Excess extraction will lead to the steam pressure being lower than the operating pressure required by the IPTB.
- of simulation blockdiagrams of thermal power plant.
- Thermal Power Library.
- African American Women Writers Historical Fiction?
- Lesbian Sex Bible: The New Guide to Sexual Love for Same-Sex Couples?
- Thermal Power Plant Simulation and Control (): Flynn Damian - BiblioVault.
- Thermal Power Library;
- The Brain Without Oxygen: Causes of Failure-Physiological and Molecular Mechanisms for Survival.
So this strategy only works with a small range of power regulation. The advantage of this strategy is that the steam can be recycled back to LPTB without modifying the whole system cycle. During the electricity peak demand period, the stored thermal energy in the TES will be discharged back to the water steam loop to increase the total electricity generation. Two strategies have been studied: the first one is to use TES to produce high temperature and high-pressure steam, which is then fed into the LPTB inlet; another is to use TES to preheat the feed water instead of using the original preheaters.
The simulation study for these two strategies is presented and analyzed in the following subsections. During the TES discharging process, part of the feed water flows into the bottom of the TES section from the deaerator, evaporates into steam and is superheated while it rises along the heat exchanger tubes in the TES, then it leaves the TES in the status of superheated steam. The steam is then fed to the LPTB inlet and produces an additional electric power output.
As part of the feed water is taken out of the deaerator, more water is needed to be pumped into the deaerator in order to maintain the steam flow rates in the HPTB and IPTB. With various valve openings, the increased steam flow rate and power output are observed. From the simulation study, the maximum flow rate of the steam generated from the TES is As a result, the corresponding overall output power is In this supercritical coal-fired power plant, there are three HP heaters and a group of LP heater.
The amount of the steam extraction is controlled by regulating valve openings. When these valves are closed, more steam will pass through the downstream turbines and produce more power. However, this operation leads to the decrease of the feed water temperature. With the TES integration, in order to maintain the feed water temperature, the feed water will bypass the preheaters and flow into TES to raise its temperature. When the valve used to extract steam for No.
When those valves for extracting steam to feed to the LP heater are closed, the feed water will bypass the LP heater and enter the TES for heating. As a result, the output power is increased to around When those valves for extracting steam to feed to the LP heater and No. This method requires no plant structure changes so it is more feasible and cost-effective although the power regulation capability is limited to a small range. The simulation results have shown that the power plant could be operated with increased flexibility within a wider range of power output through TES integration.
The TES could accumulate or release thermal energy to regulate the plant power output, therefore it offers the enhanced capability in providing the services to load shifting. The dynamic performance of the supercritical power plant with or without TES integration is compared in this section. The solid line is the power output dynamic responses with the TES integration in action, in which the output power is regulated with the support of TES charging and discharging processes while the amount of feed coal fuel input remains the constant.
The dashed line represents the power output without TES integration where the power output is directly controlled by changing the flow rate of coal feeding. It can be seen that the power plant integrated with TES shows faster dynamic responses and smoother transitions compared with the power plant without TES.
This chapter describes the simulation study of TES integration into a supercritical coal-fired power plant for efficient and flexible plant operation. The simulation results show that it is feasible to extract thermal energy from the water-steam cycle for TES charging during the off-peak time period and to discharge the stored thermal energy back to the power generation process to water steam loop during the peak demand period to boost the power generation. According to the results, following conclusions can be drawn: The flexibility of a supercritical coal-fired power plant can be improved with the TES integration.
For the TES charging process, the amount of the steam extraction needs to be restricted to a feasible range in order to maintain a stable power output. For the first TES discharging strategy, the maximum mass flow rate of generated steam is With the TES integration, the supercritical coal-fired power plant presents faster dynamic responses to the load demand changes.
The authors would like to give our thanks to Mr. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers.
Manage the Virtual Power Plant and prevent a blackout!
Login to your personal dashboard for more detailed statistics on your publications. Edited by Tolga Taner. We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals.
Downloaded: Abstract This chapter presents the recent research on various strategies for power plant flexible operations to meet the requirements of load balance.
Keywords supercritical coal-fired power plant SimuEngine thermal energy storage flexible operation load shifting. Introduction The current balance between power generation and load demand is mainly managed by regulating the output of fossil fuel power plants [ 1 , 2 ]. TES integration strategies and results This section presents the integration strategies and simulation results of a supercritical coal-fired power plant with TES.
TES charging strategies TES charging can be realized by extracting steam from different locations of the water-steam loop of the power plant and flowing the extracted steam through heat exchangers to store thermal energy during the off-peak period.