Aiming at the problem of large reactive power consumption and serious harmonic pollution in coal mine power supply system, this paper introduces a hybrid reactive power compensation and filtering scheme TCR+TSF, and analyzes the principle structure and working mode of the scheme. The control system, in addition, discusses the switching time of the TSF branch. Finally, the scheme is simulated by MATLAB. The simulation results verify the effectiveness of the scheme.
The overall structure and working principle of the TCR+TSF scheme
The TCR+TSF device is a special type of TCR+TSC hybrid static var compensator. It is generally composed of a set of phase-controlled reactors and several sets of filter branches. In order to prevent the 3rd harmonic from flowing into the grid, the TCR branch Both the TSF branch and the TSF branch are connected by a triangle. The number of harmonics generated by it includes 5, 7, 11, 13, .... In the general circuit, the harmonic content of more than 11 times has little effect on the system. Therefore, this program mainly realizes 5 times and 7 times. , 11th harmonic filtering. Here, we divide the filter into two sets of 5 TSF branches, a set of 7 TSF branches, and a set of 11 TSF branches. According to different reactive conditions of the system, different configurations of TSF branches are switched. road. It should be noted that if there are multiple TSF branches for cutting, they must be input from low to high, and vice versa, and must be cut from high to low. In addition, the capacity of the TCR branch should be slightly larger than the capacity of the TSF branch, which ensures smooth adjustment of the reactive power of the system. Figure 1 shows the overall structure of the TCR+TSF compensation device.
Figure 1 Overall structure of the TCR+TSF compensation device
The basic working principle of the TCR+TSF device is: firstly, according to the amount of reactive power that the system needs to compensate, a certain number of TSF branches are input. Since the input TSF branch capacity is constant, over-compensation may occur, and then the TCR branch is adjusted. Reactive power to compensate for partially compensated capacitive reactive power. If the TCR branch is disconnected and only all TSF branches are put into operation, the device will output the maximum capacitive reactive QCmax; if only the TCR branch is input ( 
=0), the device will output the maximum inductive reactive power QLmax.
In the TSF branch, two anti-parallel thyristors are typically connected to the system, but this limits the filter to switch quickly and frequently. Considering the operation and cost factors, the scheme of this paper uses a thyristor and a diode in reverse parallel connection to achieve control. The working mode of the TSF branch is: when the thyristor is not conducting, the diode is turned on first, and the system charges the capacitor. Ideally, the voltage across the capacitor is charged to the peak voltage of the system. At this time, the rate of change of the system voltage is zero, and the thyristor is turned on. The TSF branch began to work [8]. It can be seen from the above analysis that when the TSF branch is put into operation, the voltage across the capacitor has reached the peak value as the system voltage. Therefore, after the thyristor is turned on, the capacitor charging and discharging oscillation phenomenon does not occur, and the filtering branch is quickly input and cut off. The TSF branch adopts a delta connection mode, and the thyristor adopts a zero-crossing trigger to minimize the current impact when switching the TSF branch and the impact on the coal mine power supply system.
Control system of TCR+TSF scheme
The control system can be divided into operation and display interface, condition monitoring, controller and protection. Among them, the controller is the core of the control system. The controller selects DSP as the main control chip and adopts TI DSP 2812. It utilizes the features of fast computing speed and high precision to ensure the real-time performance and accuracy of the signal. In addition, the control algorithm is written and implemented by the DSP to determine the TCR phase signal and the TSF switching command that should be output, and send them to the independent trigger boards, and generate trigger pulses for the TCR and TSF according to the synchronization signal of the DSP main control board.
The controller can be divided into three parts: the grid signal detection circuit, the control circuit and the TSF zero-crossing trigger circuit. The grid signal detection circuit collects the voltage and current signals in the power grid, and quickly detects the change of the reactive power of the coal mine power supply system through calculation, inputs the corresponding TSF branch according to the reactive power value to be compensated, and then calculates the capacitive reactive power of the system. By controlling the TCR trigger delay angle α, the purpose of dynamically and smoothly adjusting the reactive power is achieved, and finally the effect of filtering harmonics is achieved while compensating for reactive power. Figure 2 shows the structure of the control system.
Figure 2 TCR + TSF control system structure
We offer a premium quality range of 520 mm Width Swan Neck Type Radiator in the market. This is sturdily fabricated using superior grade material and modern machinery in sync with set industrial norms and standards. 520 mm Width Swan Neck Type Radiator is known for its high efficiency, easy installation, low maintenance and better durability. This makes it stand apart from other radiators in the market. We offer this at highly pocket- friendly prices within a stipulated period of time.
Swan neck type of radiators are accessible with bend pipes at space restraint areas and can be made accessible with or without inserted sections provisional on the heat dissipation and oil quantity needed.
Swan Neck Radiator,Leakage Proof Swan Neck Radiator,Weather Proof Swan Neck Radiator,Anti Corrosion Swan Neck Radiator
Shenyang Tiantong Electricity Co., Ltd. , https://www.ttradiator.com