Multi-region fuzzy logic controller with local PID controllers for U-tube steam generator in nuclear power plant

Abstract

In the paper, analysis of multi-region fuzzy logic controller with local PID controllers for steam generator of pressurized water reactor (PWR) working in wide range of thermal power changes is presented. The U-tube steam generator has a nonlinear dynamics depending on thermal power transferred from coolant of the primary loop of the PWR plant. Control of water level in the steam generator conducted by a traditional PID controller which is designed for nominal power level of the nuclear reactor operates insufficiently well in wide range of operational conditions, especially at the low thermal power level. Thus the steam generator is often controlled manually by operators. Incorrect water level in the steam generator may lead to accidental shutdown of the nuclear reactor and consequently financial losses. In the paper a comparison of proposed multi region fuzzy logic controller and traditional PID controllers designed only for nominal condition is presented. The gains of the local PID controllers have been derived by solving appropriate optimization tasks with the cost function in a form of integrated squared error (ISE) criterion. In both cases, a model of steam generator which is readily available in literature was used for control algorithms synthesis purposes. The proposed multi-region fuzzy logic controller and traditional PID controller were subjected to broad-based simulation tests in rapid prototyping software -Matlab/Simulink. These tests proved the advantage of multi-region fuzzy logic controller with local PID controllers over its traditional counterpart.

Dynamic model of nuclear power plant steam turbine

“…It was modeled according to (20)(21). Dead space has very significant contribution to the dynamic character of presented NPP steam turbine model.…”

“…Dead space has very significant contribution to the dynamic character of presented NPP steam turbine model. Submodel is based on time derivative (20) of the pressure within dead space which determines an input for the first stage of steam turbine. Derivative time constant τ i (21) was proven [18] to be a constant value within the range from 43 up to 100 percent of the steam turbine power.…”

“…Derivative time constant τ i (21) was proven [18] to be a constant value within the range from 43 up to 100 percent of the steam turbine power. (20) and vents p iV (41). Pressure of stage groups p iLP (except last group of stages) in the LP part can be calculated as proportional to pressure of reheater p p (24).…”

“…Paper authors take part in a research team whose research focus on solving the problems related to modeling, diagnostic and control of NPP e.g. [3,12,15,16,17,20]. This paper presents a dynamic, multivariable, nonlinear model of NPP steam turbine based on the approach [18] and compares it with the modified static one presented in [12].…”

Optimal feed-water level control for steam generator in nuclear power plant based on meta-heuristic optimization

“…Kavaklioglu (2014) proposed a predictive control algorithm via support vector regression-based models to control the water level of UTSG. Puchalski et al (2015) proposed a multiregion fuzzy logic controller. A suitable optimization tasks with integrated squared error criterion as a cost function is solved to acquire the local parameters of PID controllers.…”