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International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN 2249-6890 Vol. 3, Issue 4, Oct 2013, 69-76 Š TJPRC Pvt. Ltd.


Department of Mechanical Engineering, Faculty of Technology & Engineering, Charotar University of Science & Technology, Changa, Anand, Gujarat, India


Department of Mechanical Engineering, Birla Vishvakarma Mahavidyalaya, V. V. Nagar, Anand, Gujarat, India 4

Department of Automobile Engineering, Ipcowala Institute of Technology, Dharmaj, Anand, Gujarat, India.

ABSTRACT Power plants require continuous monitoring and inspection at frequent intervals. In the recent times, thermal power generation has under gone long process of modification right from its conventional working principles to automation using technology in the form of DCS, PLC, SCADA (Supervisory Control and Data Acquisition) etc. An automated system improves the system efficiency, plant monitoring, productivity and the operation management of the plant. This paper focuses on various aspects of automation of laboratory based mini-thermal power plant and virtual simulation of same. Automatic plant operation and monitoring is achieved by automatic controllers; indicators placed on the panel displays the status of valves, sensors and actuators used in the automation of the plant. Simulation model provides a good understanding and better visual idea about the real-time performance of lab based mini-thermal power plant, investigates complex operations and displays failure patterns and aids in remote monitoring and control through SCADA.

KEYWORDS: Mini-Thermal Power Plant, Automation, Virtual Simulation, Remote Monitoring and Control, SCADA INTRODUCTION Indian thermal power plants offer enormous potential for efficiency improvement. Automatic/semi-automatic control may save operational costs and operational time. Therefore, minimizing operation costs and improving efficiency are key objectives of the operation and maintenance of power plant. This paper aims to achieve this objective through automation of laboratory based mini-thermal power plant. The concept is aimed at developing virtual laboratories to facilitate teaching learning process. The immediate benefits to the students are that they learn the concept of virtual instrumentation, plant automation and plant monitoring. The focus area is various aspects of automation of laboratory based mini-thermal power plant and virtual simulation of same. The main objective is to provide the students idea about working of a power plant, to project the benefits of virtual simulation in practical laboratories, to create an understanding about different types of sensors and actuators used in power plant instrumentation, and to create a possibility of remote access of plant operation using Supervisory Control and Data Acquisition (SCADA).

EXPERIMENTAL SET UP OF LABORATORY BASED MINI THERMAL POWER PLANT The test rig consists of a steam turbine coupled to an alternator both mounted on a suitable base plate. The Boiler is oil fired. Steam from the boiler passes through a flow meter and to the turbine. Suitable taps are provided to sample the steam and determine its quality and to measure its pressure and temperature. A main valve is used to control the flow rate


Bindu Pillai, Dhara Trivedi, Vishal Mehta & Nilam Patel

from the boiler. The output shaft of the turbine is coupled to the alternator. A panel mounted tachometer is provided to measure the turbine speed. A set of electrical bulbs and a water rheostat are used to utilize the electrical power produced by the alternator. Exhaust steam from the turbine is let out to the atmosphere or to a condensor using the exhaust valves. A separate centrifugal pump is provided to circulate the cooling water through the condensor. An evacuating pump is used to remove the condensate from the condensor. The setup is manually operated with a power generation capacity of 5kVA, alternator rotating at 3000 r.p.m producing maximum of 3kW of which 1kW is used to illuminate the bulbs and rest is bypassed to the rheostat for heating water in the tank. The used steam is passed through the condensor and converted to water. The fuel (diesel) consumption is 40 litres/hour and the boiler efficiency is 22%. Experimental set-up of mini thermal power plant is shown in figure 1.

Figure 1: Experimental Set-up of Mini Thermal Power Plant

POWER PLANT AUTOMATION Automation of the mini thermal power plant was carried out in 3 phases:

Feasibility study of automating the plant and creating virtual simulation- The problems of the existing set-up was identified and the scope of automating the plant was worked out. To support the idea of automation, first a virtual simulation model was created.

Identifying the required sensors and actuators, its installation and testing- To address the problems with the existing set-up different manually operated valves were replaced by motorized valves, sensors and actuators were introduced at the required location. The installation was carried out and the entire set-up was automated. The automated set-up was then tested for its performance in terms of efficiency, plant operation and monitoring.

Implementation of SCADA for the mini thermal power plant- Once the automated set-up was successfully tested the next step was to establish remote access to the plant operation by implementing SCADA.

Problems with the Existing Set-up The following problems were identified with the existing set-up: 

No diesel pump to feed diesel into the diesel storage tank.

No indicator for water level and diesel level for water tank and diesel tank respectively.

All the valves of power plant setup are manually operated.

No accurate devices for the measurement of the process parameters.


Automation and Virtual Simulation of Laboratory Based Mini Thermal Power Plant

Skilled man power required for operating the complete power plant.

No monitoring system available at power plant setup.

Scope of Automating the Plant The existing plant was manually operated one and hence there was a need to replace the manually operated valves with the motorized valves. To sense the liquid level, pressure and temperature, respective sensors had to be identified. Some modification in pipelines was required and fianlly the whole system had to be integrated with PID controller. Virtual Simulation of Mini Thermal Power Plant The simulation of the entire automated setup of laboratory based mini thermal power plant was carried out in LabVIEW-2010 by using DSC (Data logging and Supervisory Control) module. The Virtual simulation of lab based mini thermal power plant is shown in figure 2. To start the plant put on the start (toggle) switch. If the tank is empty at initial stage then the level sensor S2 will sense the signal and it will pass feedback signal to cRIO (PID Controller) which will actuate Valve1 and allow water to feed into the water tank from water sump by Pump1. As level reaches up to 1000 mm, S1will sense the signal and pass the feedback signal to cRIO (PID Controller)

and Pump1 immediately stops,

simultaneously Valve2 will be open. It remains fully open during the operation of the plant and Pump3 continuously supplies water to the boiler.

Figure 2: Virtual Simulation of Mini Thermal Power Plant In the same way if the oil tank is empty , level sensor S4 will sense the signal and it will give a feedback signal to cRIO (PID Controller) which will actuate Valve3 and it will open. When the oil level reaches upto 700 mm, the level sensor S3 will sense the signal and actuate Valve4 and it will be closed. When the level goes below 200mm, Valve3 will open again. The initial steam temperature in the boiler is 29˚C. The bypass valve remains fully open until the steam temperature reaches 135 ˚C (the maximum limit is 190 ˚C). At this temperature, the bypass valve will be closed and


Bindu Pillai, Dhara Trivedi, Vishal Mehta & Nilam Patel

Valve5 will be open. Steam passes through the turbine, and in between there is a pressure transmitter and a temperature sensor T1 mounted on the pipe line which will sense the pressure and temperature of the steam. As the steam temperature crosses 170 ˚C the globe valve opens and the steam enters the turbine which in turn rotates the alternator connected to it. At 3000 rpm it generates 3kW power out of which 1kW is used to lit the 3 bulbs shown in the out-put panel. The used steam is passed through the condensor and converted to water. Temperature sensor T2 and T3 sense the inlet and outlet water temperature. The monitoring panel in the simulation reflects the status of the valves, pumps and sensors. Red color indicates “OFF” and green indicates “ON” status in the simulation of any device at a particular time. Benefits of Virtual Simulation 

Virtual simulation is useful for understanding the real time working of power plant.

The simulation can be used as a virtual lab to give training to the students & professionals.

Installation and Testing During the installation the manually operated valves of the existing set-up are replaced by the motorised valves. Globe valve is located at the outlet pipe of the boiler. It is actuated only when the temperature of steam reaches 170˚C and pressure of steam reaches 5bar. All other manually operated valves are replaced by automatic ball valves. Electric solenoid actuator is used to actuate the valves. Level sensor is installed in the water tank and the diesel tank to sense the water level & diesel level, total four thermocouples are used to sense temperature- temperature of steam at boiler outlet, inlet temperature of turbine, inlet temperature of the condensor and outlet temperature of the condensor, one pressure transmitter is used to sense the pressure of the steam at boiler outlet and all the sensors are integrated with the valves to provide signals to actuate them. After the required modification in pipeline the whole system was integrated with PID controller as shown in figure 3.

Figure 3: Automated Set-up of Laboratory Based Mini Thermal Power Plant Benefits of Power Plant Automation 

Indication of water level and diesel level in the tank can be acknowledged with the help of level sensor.

Automatic valves reduce operating time of plant.

PID controller controls the globe valve automatically as per the preset temperature and pressure.

Produced power is utilized for charging an I.C. Engine battery charger, to run pump for recirculation of water to the condensor, to run fans of thermal engineering laboratory.

Automation and Virtual Simulation of Laboratory Based Mini Thermal Power Plant


Improvement in boiler efficiency by 6%.


Automatic controller based operation improved the process monitoring and made plant operation easy.


Supervisory Control and Data Acquisition (SCADA) of Mini Thermal Power Plant SCADA (supervisory control and data acquisition) generally refers to industrial control systems, computer systems that monitors and controls industrial, laboratory, infrastructure or facility-based processes. A SCADA simulation of a laboratory based mini thermal power plant was developed using LabVIEW-2010 data logging and supervisory control (DSC) module which has a capacity to supervise the plant operation and perform data acquisition.

Features of SCADA Simulation Supervisory Control of Mini Thermal Power Plant The SCADA system of mini thermal power plant includes mini thermal power plant layout and indicators for onoff condition of various valves and sensors of plant. Data Acquisition in Mini Thermal Power Plant The main objective of data acquisition system is to acquire data from temperature sensor, pressure sensor and level sensor of mini thermal power plant. Data acquisition tab is shown in figure 4. Operator can monitor data acquired from various sensors like temperature sensor, pressure sensor and level sensor. Value of steam temperature and steam pressure, at a particular time, can be monitored through this simulation along with High and Low position of the level sensor. Process Monitoring with PID Controller Operator can monitor position of globe valve and motorized damper with help of PID controller and based on the preset temperature and pressure values, control the % opening of the valve. Historical Data SCADA simulation features viewing of historical data in the form of plots. Operator can view data of various process parameters such as tmeperature at globe valve, temperature at condensor inlet and outlet acquired.

Figure 4: SCADA Simulation


Bindu Pillai, Dhara Trivedi, Vishal Mehta & Nilam Patel

CONCLUSIONS Due to automation of the plant the boiler efficiency was improved from 22% to 28%. Fuel consumption was reduced from 40litres/hour to 33litres/hour. Plant operation is more efficient due to automatic valves, sensors and PID controller. Better utilisation of the output to charge I.C. Engine battery, lighting bulbs and fans of the laboratory and driving the condensate pump. Power plant operation can be monitored through SCADA from a remote location.

ACKNOWLEDGEMENTS The authors wish to thank Dr. Piyush Gohil, Professor & Head, Mechanical Engineering Department and Dr. N.D. Shah, Principal-Faculty of Technology and Engineering (Chandubhai S. Patel Institute of Technology- Changa) Charotar University of Science and Technology, Changa for their encouragement and support in undertaking the research work. Special thanks to the Management for their financial and moral support.


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