scholarly journals Validation of Complex Control Systems with Heterogeneous Digital Models in Industry 4.0 Framework

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 62
Author(s):  
Kirill Semenkov ◽  
Vitaly Promyslov ◽  
Alexey Poletykin ◽  
Nadir Mengazetdinov

The precise evaluation of the system design and characteristics is a challenge for experts and engineers. This paper considers the problem of the development and application of a digital twin to assess cyberphysical systems. We analyze the details of digital twin applications at different lifecycle stages. The work reviews and summarizes properties of models concerning the digital and physical components of a cyberphysical system (CPS). The other issue of a CPS is increasing cybersecurity threat for objects, so special attention is paid to the heterogeneous digital twin usage scenarios to improve CPS cybersecurity. The article also details the heterogeneous digital twin’s implementation for a real upper-level control system of a nuclear power plant. The presented heterogeneous digital twin combines virtual machines with real equipment, namely hardware-in-the-loop (HiL) components. The achievements and drawbacks of the implemented model, including single timescale maintaining challenges, are discussed.

Author(s):  
Chen-Lin Li ◽  
Chiung-Wen Tsai ◽  
Chunkuan Shih ◽  
Jong-Rong Wang ◽  
Su-Chin Chung

This study used RETRAN program to analyze the turbine trip and load rejection transients of Taiwan Power Company Lungmen Nuclear Power Plant’s startup test at 100% power and 100% core flow operating condition. This model includes thermal flow control volumes and junctions, control systems, thermal hydraulic models, safety systems, and 1D kinetics model. In Lungmen RETRAN model, four steam lines are simulated as one line. There are four simulated control systems: pressure control system, water level control system, feedwater control system, and speed control system for reactor internal pumps. The turbine trip event, at above 40% power, triggers the fast open of the bypass valves. Upon the turbine trip, the turbine stop valves close. To minimize steam bypassed to the main condenser, recirculation flow is automatically runback and a SCRRI (selected control rod run in) is initiated to reduce the reactor power. The load rejection event causes the fast opening of the bypass valves. Steam bypass will sufficiently control the pressure, because of their 110% bypass capacity. A SCRRI and RIP runback are also initiated to reduce the reactor power. This study also investigated the sensitivity analysis of turbine bypass flow, runback rate of RIPS and SCRRI to observe how they affect fuel surface heat flux, neutron flux and water level, etc. The results show that turbine bypass flow has larger impacts on dome pressure than RIPS runback rate and SCRRI. This study also indicates that test criteria in turbine trip and load rejection transients are met and Lungmen RETRAN model is performing well and applicable for Lungmen startup test predictions and analyses.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Liming Zhang ◽  
Hongyun Xie ◽  
Qizhi Duan ◽  
Chao Lu ◽  
Jixue Li ◽  
...  

Power level control is one of the critical functions in the instrument and control system of nuclear power plants (NPPs). In most power level control systems of NPPs, the power level or average neutron flux in reactor cores provided by out-of-core neutron sensors are usually measured as feedback of power control systems, while, as critical measuring devices, there is a risk of damage to out-of-core neutron sensors. For improving the operation reliability of NPPs under the neutron sensors’ failure, a power control system based on power observer is developed in this work. The simulation based on NPP simulator shows the power control system based on the observer is effective when neutron sensors fail.


Author(s):  
Meng Lin ◽  
Zongwei Yang ◽  
Dong Hou ◽  
Pengfei Liu

In China, more and more Nuclear Power Plant (NPP) will be constructed in the near future years, and Main Control Room (MCR) will introduce digital Instrumentation and Controls systems (I&C) technique. I&C system of nuclear power plant consists of Control Systems, Reactor Protection System and Engineered Safety Feature (ESF) Actuation System. For example, I&C system of LinAo Phase II NPP has adopted SIEMENS TXP and TXS I&C, which is being constructed in Guangdong province, China. In this engineering project, Chinese engineers are responsible for all the configuration of actual analog and logic diagram. Before the phase of real plant testing on the reactor, engineers want to make sure that configuration is right and control functions can be accomplished, so primary Verification and Validation (V&V) of I&C works were done. One way is checking the diagram configuration one by one according to the original design. There are two main disadvantages. One is diagram is so complex that workload is very large and engineers will make mistake. Another is even engineers have read every logic, but they still cannot know the final results and function of a complex control system. So another effective V&V way is applying NPP engineering simulator to do virtual test. According to LinAo Phase II NPP design, we develop one simulator to construct a virtual NPP model as a basis, which can provide plant operation parameters and can also accept control signal from I&C, then give response to it. Through this way, we don’t need to know the exact diagram, and just observe input and output of I&C to make sure that the final results is right and functions have been accomplished. In this way, it is need to transfer signals between simulator and I&C. For keeping the original software and hardware structures of SIEMENS Distributed Control System (DCS), we use one set of data acquisition (DAQ) equipments to build a connection between the engineering simulator (software) and SIEMENS DCS I/O cabinet (hardware), and the interface is standard 4–20mA direct current and 0–48V direct voltage. This way is convenient for expansion to other digital I&C V&V. After these two V&V works, we can then build the confidence of digital I&C control function. As an application research, we mainly focus on V&V of digitalized control systems and selected several Reactor Control (RRC) systems as examples, including pressurizer pressure and water level control, steam generator water level control. In this paper, we will introduce the way of applying engineering simulator to do V&V works, the structure of our simulator, the function of different block, and primary V&V results. Moreover, we will have ideas on the future application of this methodology to V&V of Reactor Protection System and ESF Actuation System.


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