control poster.pptx
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This document discusses modeling steam turbine control systems. It presents both nonlinear and linear modeling approaches. For the linear model, equations are derived to describe the pressure and steam mass flow through turbine sections, with the pressure proportional to stored steam mass and steam flow proportional to inlet pressure. A block diagram model of the linear plant is shown with control inputs of valve lifts and output of power. For the nonlinear model, steam flow is modeled using thermodynamic equations rather than assumed linear relationships. Both models have the same inputs and output but the nonlinear model considers additional system dynamics and couplings.
![STEAM TURBINE MODELING
NONLINEAR /LINEAR
Salahaddin
University
College Of
Engineering
Introduction BLOCK DIAGRAM
Prepared by:
Muhammad Jawhar
Zana Haydar
Supervised by:Dr chalang
Steam turbine control systems are being designed
with today’s technology to operate a turbine in a safe
and reliable manner. There are many
considerations to be taken when choosing a
controller for steam turbine applications. Many
benefits may be realized by choosing the proper
steam turbine control system, whether it is a
mechanical, an electrical or a programmable
controller system. This paper presents the basic
concepts of the steam turbine control system and
develops the fundamentals of the speed control. Using
Matlab /Simulink software facilities, have been
simulated the speed variations, of the steam turbine-
load unit, connected with a mechanical-hydraulic
system, than the speed deviations of the steam
turbine-load unit, to different load deviations,
proportional and proportional-integrative control
algorithms.
Rewriting the derived equations as block diagrams
results in the plant described by Figure 5.
Control inputs of the plant are the valve lifts hMS and
hRS, output is the power P. The
states of the linear model (3.1), (3.3) correspond to
the stored steam masses.
Using the equations derived above, a non-linear
simulation model for a HP-IP-LP turbine
in form of a block diagram is developed as depicted
in Figure 6.
The steam flow through the re-heater was modelled
as the flow through a pipe.
Consequently, transient effects of heat transfer are
neglected.
Note that the derived system has the same control
inputs hMS and hRS, and output P as
has the linear system, depicted in Figure 5. The
states of the non-linear model also
correspond to the stored steam masses. Coupling to
the environment is given through the
steam generator pressure and the condenser
pressure. Thus through the condenser
pressure, the non-linear model features one more
‘input’ than the linear model.
Non-Linearity
In a second approach, the idea of the storage being a mass storage
according to Equation
(3.1) is maintained, whereas the linearity in steam mass flow is
abandoned. Instead, steam
mass flow is modelled according to the thermodynamic standard
description; see, for
example, [4]. Thus, it is distinguished between flow through a pipe, a
turbine (section) and
a valve.
Let p0, v0 and m0 denote the steam parameters and mass flow,
respectively, at a given
design condition. Assuming ideal gas properties and using T0 for the
absolute temperature
at design condition, the equation
Linear Turbine Model Firstly, each turbine section is described through
linear relationships. A storage is simply viewed as a steam mass storage,
hence
3.1
Furthermore, it is assumed that the pressure in a storage is proportional to the
stored mass of steam: 3.2
Equation (3.2) holds true for ideal gases.
Considering the overall turbine, it is widely known that – in steady state
operation – the steam mass flow through the turbine is proportional to the
pressure at the first stage
(inlet) and that, except at low load
conditions, the power output is almost
proportional to the steam mass flow
through the turbine. Generalizing this observation to a turbine section, the
following equations are derived to describe the pressure and the steam mass
flow through a turbine section. 3.3
Assumptions (3.2) and (3.3) hold true in a wide set of steady state
operating points . However, the respective proportional constants depend on
NONLINEAR
/LINEAR
In simple terms, a steam turbine works by
using a heat source (gas, coal, nuclear,
solar) to heat water to extremely high
temperatures until it is converted into
steam. As that steam flows past a turbine’s
spinning blades, the steam expands and
cools. The potential energy of the steam is
thus turned into kinetic energy in the
rotating turbine’s blades. Because steam
turbines generate rotary motion, they’re
particularly suited for driving electrical
generators for electrical power generation.
The turbines are connected to a generator
with an axle, which in turn produces energy
via a magnetic field that produces an
electric current.](https://image.slidesharecdn.com/controlposter-220425215920/85/control-poster-pptx-1-320.jpg)
control poster.pptx
- 1. STEAM TURBINE MODELING NONLINEAR /LINEAR Salahaddin University College Of Engineering Introduction BLOCK DIAGRAM Prepared by: Muhammad Jawhar Zana Haydar Supervised by:Dr chalang Steam turbine control systems are being designed with today’s technology to operate a turbine in a safe and reliable manner. There are many considerations to be taken when choosing a controller for steam turbine applications. Many benefits may be realized by choosing the proper steam turbine control system, whether it is a mechanical, an electrical or a programmable controller system. This paper presents the basic concepts of the steam turbine control system and develops the fundamentals of the speed control. Using Matlab /Simulink software facilities, have been simulated the speed variations, of the steam turbine- load unit, connected with a mechanical-hydraulic system, than the speed deviations of the steam turbine-load unit, to different load deviations, proportional and proportional-integrative control algorithms. Rewriting the derived equations as block diagrams results in the plant described by Figure 5. Control inputs of the plant are the valve lifts hMS and hRS, output is the power P. The states of the linear model (3.1), (3.3) correspond to the stored steam masses. Using the equations derived above, a non-linear simulation model for a HP-IP-LP turbine in form of a block diagram is developed as depicted in Figure 6. The steam flow through the re-heater was modelled as the flow through a pipe. Consequently, transient effects of heat transfer are neglected. Note that the derived system has the same control inputs hMS and hRS, and output P as has the linear system, depicted in Figure 5. The states of the non-linear model also correspond to the stored steam masses. Coupling to the environment is given through the steam generator pressure and the condenser pressure. Thus through the condenser pressure, the non-linear model features one more ‘input’ than the linear model. Non-Linearity In a second approach, the idea of the storage being a mass storage according to Equation (3.1) is maintained, whereas the linearity in steam mass flow is abandoned. Instead, steam mass flow is modelled according to the thermodynamic standard description; see, for example, [4]. Thus, it is distinguished between flow through a pipe, a turbine (section) and a valve. Let p0, v0 and m0 denote the steam parameters and mass flow, respectively, at a given design condition. Assuming ideal gas properties and using T0 for the absolute temperature at design condition, the equation Linear Turbine Model Firstly, each turbine section is described through linear relationships. A storage is simply viewed as a steam mass storage, hence 3.1 Furthermore, it is assumed that the pressure in a storage is proportional to the stored mass of steam: 3.2 Equation (3.2) holds true for ideal gases. Considering the overall turbine, it is widely known that – in steady state operation – the steam mass flow through the turbine is proportional to the pressure at the first stage (inlet) and that, except at low load conditions, the power output is almost proportional to the steam mass flow through the turbine. Generalizing this observation to a turbine section, the following equations are derived to describe the pressure and the steam mass flow through a turbine section. 3.3 Assumptions (3.2) and (3.3) hold true in a wide set of steady state operating points . However, the respective proportional constants depend on NONLINEAR /LINEAR In simple terms, a steam turbine works by using a heat source (gas, coal, nuclear, solar) to heat water to extremely high temperatures until it is converted into steam. As that steam flows past a turbine’s spinning blades, the steam expands and cools. The potential energy of the steam is thus turned into kinetic energy in the rotating turbine’s blades. Because steam turbines generate rotary motion, they’re particularly suited for driving electrical generators for electrical power generation. The turbines are connected to a generator with an axle, which in turn produces energy via a magnetic field that produces an electric current.