| This paper introduces the electric railway series | | | | system. As with the control PLC reliability, |
| compensation device working principle and the role | | | | configuration flexibility, small size, powerful |
| of Thyristor AC electronic switch. Highlighted | | | | functions, fast and good scalability, easy |
| 1600A1000V thyristor electronic switches in the | | | | maintenance, not only reduces the hardware |
| programmable logic controller communication (PLC) | | | | connection, improved reliability, and by modifying |
| system hardware and software and its installation | | | | the program can adapt to new requirements |
| in the role. Finally on the device can do a brief | | | | Therefore, the exchange of electronic switch SCR |
| summary of the technical. See more exciting | | | | 1600A1000V selected minicomputer Siemens S7? |
| information | | | | 200 series of PLC control system as the core |
| 1 Overview Electric Of Railway (hereinafter | | | | component. |
| referred to as electric iron) related to the | | | | 3 PLC control system structure and its role in the |
| harmonic problem is a common power quality and | | | | exchange of electronic switches |
| electric iron smooth building issues, my office | | | | (1) hardware structure and its role |
| started from the 80's efforts to study and solve | | | | In this device, PLC control systems, |
| the problem. Series Compensator To a certain | | | | minicomputers selected Siemens S7? 200 series |
| extent, address this issue, and because of its | | | | of the CPU222, analog expansion module EM231 |
| technical difficulty is low, investment in small, easy | | | | and text display TD200. Distribution of resources |
| to implement, thus the double-track electrified | | | | available hardware system diagram as shown |
| railway in the single renovation project has | | | | below: |
| demonstrated a great advantage. | | | | CPU222 PLC control system is the CPU unit, |
| Series compensation device works in the heavy | | | | responsible for receiving all of the switching |
| load of electric railway power lines, line inductance | | | | capacity and through the A / D converted analog |
| serious losses by investing in pre-series in the loop | | | | input and output under the control of logic control |
| Capacitor Change the circuit load type, so as to | | | | signal; EM231 responsible for the main circuit |
| achieve to improve network pressure and | | | | voltage, current signal for A / D conversion, and |
| improve the power factor effect. Shown in Figure | | | | transport to the CPU unit conversion result; |
| 1. As the power of iron overload is an exercise | | | | TD200 text display output unit responsible for |
| load, load size is not only related to the number of | | | | monitoring CPU state, according to a combination |
| locomotives, but also with the locomotive truck, | | | | of the various output indicators of the condition |
| locomotive operations, lines of slope and other | | | | the thyristor electronic switches running status |
| factors closely related. Capacitor switching | | | | and fault type. |
| operation is also quite frequent. If you use the | | | | (2) Formation and function of software |
| machine (with contact) switches, because of its | | | | In this device, PLC control system, the software |
| switching time relative to the network then the | | | | has two parts: a text display software and logic |
| phase of pressure, the contact of zero absorption | | | | control software. Stored in a text display text |
| in the non-timely and will be due to large | | | | display software to display all the text and the |
| short-circuit power capacitor current impact, the | | | | CPU unit output combinations correspondence. |
| electrical life is usually Only dozens of times. | | | | Thyristor logic control software includes all the |
| Therefore, series compensation device must use | | | | electronic switch control logic, the software |
| thyristor AC Electronic Switch to achieve zero | | | | structure of the main program by the 1, 2 |
| power capacitor switching. | | | | sub-programs, two timer interrupt program |
| 2 SCR AC electronic switch control system | | | | constitutes. Its main function is: According to the |
| requirements and PLC Selection | | | | control requirements, to achieve the voltage and |
| Exchange electronic switch thyristor main circuit | | | | current detection, timely issue of trigger signals, |
| composed of two anti-parallel thyristor branch | | | | as well as over voltage, over current, fan, Power |
| structure, each branch formed by two parallel | | | | supply Various categories such as fault detection |
| thyristor, a total of four thyristors used tube | | | | and alarm signals in time, to achieve protection. |
| (connection mode shown in Figure 2). In | | | | The software flow chart shown in Figure 4. |
| accordance with the electrical Chemical industry | | | | 4 Thyristor control strategy Thyristor AC |
| Process design requirements, SCR AC electronic | | | | electronic switch is a device connecting the core |
| switch installed in the traction transformer near | | | | components of compensation, thyristor Thyristor |
| the mobile home, the combined application | | | | control strategy is the key to the exchange of |
| condition of the device on the control system the | | | | electronic switch technologies. To achieve zero |
| following requirements: | | | | trigger thyristors to be dependent on the main |
| (1) should have a high degree of reliability, to | | | | circuit voltage of phase synchronization, and once |
| meet the electricity for the grid iron is running a | | | | the thyristor device, synchronization signal will |
| long-term objective requirements; | | | | disappear, this is the thyristor trigger circuit design |
| (2) should have a sound accident alarm system, | | | | is important to note One of the problems. In |
| after the failure should be directed to the fault | | | | addition, the thyristor does not turn, its withstand |
| type, fault-free operation should be instructed out | | | | voltage and the voltage power capacitors to |
| of the power capacitor switching state; | | | | withstand the same phase, while the conduction |
| (3) should have a sound logic control and | | | | circuit after the change because the circuit occurs |
| automatic protection function; | | | | a transition process, which is designed to note |
| (4) shall ensure that the thyristor is triggered at | | | | thyristor trigger circuit the problems. |
| the crossing point of voltage; | | | | 5 Conclusion |
| (5) should have good electromagnetic | | | | PLC integration as high anti-interference ability, |
| compatibility, to adapt to traction Transformer | | | | programming is simple, the system easy to |
| substation Field of complex electromagnetic | | | | develop, maintain and upgrade advantages, |
| environment. | | | | combined with text display can clearly understand |
| Complete control of electronic switches can be in | | | | the instructions of the thyristor conduction, and |
| three ways: Development of special control using | | | | display all types of cut-off state fault state, the |
| integrated circuit board; microcomputer and | | | | use of PLC control system of thyristor AC |
| peripheral circuits developed using the special | | | | electronic switch of simple structure, easy |
| control circuit board; expansion module | | | | maintenance and high reliability, maintainability and |
| development using PLC and dedicated control | | | | flexibility. |