Simulation and experimental studies of haulage drive system in an underground coal mine for energy conservation

Abstract

The field study is carried out in GDK 10A incline (an underground coal mine) of “The Singareni Collieries Company Limited”(The SCCL). The man riding system is used in GDK 10A incline for transportation of men to different levels in underground by using two haulage drive systems (each 150hp). One drive system is used to transport men from surface to 8th level (8L) and another drive is used from 8L to 42nd level (42L). Energy consumption was calculated for each drive system for up the gradient and down the gradient i.e. 1 in 4. In the Department of Mining Engineering, a laboratory set-up for mine haulage drive system was fabricated using 3hp slip ring induction motor, similarly two man riding haulage drive system used in GDK 10A incline (field). The energy consumptions is measured using conventional control with different combination of gradients and loads, for both up the gradient and down the gradient. The experimental study in the laboratory is also carried out on 3hp motor. The laboratory set-up is suitably modified for carrying out experiments by micro controller method. The micro controller experimental setup consisting of IGBT based speed control drive unit by using AT Mega 32 micro controllers are used to implement with proper control algorithms. The energy consumption is measured using micro controller method with different gradients and loads, for both up the gradient and down the gradient. The laboratory experimental results of both methods (i.e conventional and micro controller) are presented. Experimental results are in good agreement with the simulation results. The mathematical modeling of power requirement in general is done for haulage drive system for forward and reverse direction on inclined plane with different loads. The machine model is developed in the stator flux reference frame. Mathematical modeling of conventional drive system and micro controller (static Kramer) drive system for 3hp laboratory experimental study and 150hp underground haulage drive is also done. The principle of operation and control philosophy are explained in detail in the thesis. The dynamic equations for the power circuit which are derived from stationary and synchronous reference frames are explained in the thesis. The design of voltage controller, current controller and of rotor controller of open loop and closed loop system are also discussed in the thesis.ii The computer software package MATLAB/SIMULINK is used to simulate the 3hp laboratory experimental haulage drive system (i.e. with slip ring induction motor) and micro controller haulage drive system. Similarly two man riding haulage systems in an underground coal mine (i.e. one 150hp hauler serving from surface to 8th level and another serving from 8th level to 42nd level) are modeled for both up the gradient and down the gradient and simulation is carried out using field data. The results of simulated, experimental and field for methods, (i.e. conventional and microcontroller) are presented and compared. The slip power recovered in both methods is studied and found that the values are varied from 1.644 kWh to 3.260 kWh (for 150hp haulage drive system) and from 0.088 kWh to 0.143 kWh (for 3hp experimental). The cost for 150hp hauler drive system is calculated by taking data for energy consumption (i.e. power, time and number of trips) for 1 year for the conventional method. The cost for 150hp haulage drive system is also calculated based on simulation results of both conventional and microcontroller method. It is found that difference in cost for 150hp haulage drive system in an underground coal mine for conventional method based on field study results and simulation results on average is Rs.49,19,611/- and for micro controller method based on field study results and simulation results on average is Rs.45,86,661/-. Similarly, cost for 3hp experimental haulage drive system for both methods (i.e. conventional and micro controller) is calculated by using experimental data and compared with cost estimates based on simulation results. The difference between cost analysis based on experimental and simulation results for the conventional method is Rs.8437.61/ - and microcontroller method is Rs.7492.13 /-. In the present study, 8% to 9% of slip power is recovered by adopting the microcontroller based control technique.