* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Hybrid Railway Power Quality Conditioner (HPQC)
Standby power wikipedia , lookup
Pulse-width modulation wikipedia , lookup
Power factor wikipedia , lookup
Wireless power transfer wikipedia , lookup
Variable-frequency drive wikipedia , lookup
Power inverter wikipedia , lookup
Electrical substation wikipedia , lookup
Stray voltage wikipedia , lookup
Power over Ethernet wikipedia , lookup
Audio power wikipedia , lookup
Power MOSFET wikipedia , lookup
Electric power system wikipedia , lookup
Electrification wikipedia , lookup
History of electric power transmission wikipedia , lookup
Power engineering wikipedia , lookup
Power electronics wikipedia , lookup
Distribution management system wikipedia , lookup
Buck converter wikipedia , lookup
Voltage optimisation wikipedia , lookup
Three-phase electric power wikipedia , lookup
Alternating current wikipedia , lookup
ANALYSIS OF DC LINK OPERATION VOLTAGE OF A HYBRID RAILWAY POWER QUALITY CONDITIONER AND ITS PQ COMPENSATION CAPABILITY IN HIGH SPEED CO-PHASE TRACTION POWER SUPPLY ABSTRACT: Hybrid Railway Power Quality Conditioner (HPQC) is newly proposed for its effective reduction in DC link operation voltage while providing similar power quality compensation in co-phase traction power supply compared to conventional railway power quality conditioner (RPC). However, reduction in HPQC operation voltage limits its power quality compensation capability. For instance, the previously proposed HPQC design based on minimum operation voltage under fixed rated load has minimum power quality compensation capability. Under practical conditions when load varies, the required HPQC active and reactive compensation power also changes. The DC link operation voltage of HPQC may therefore need to be enhanced to increase its power quality compensation capability. Therefore in this paper, the relationship between DC link voltage of HPQC and its power quality compensation capability, as well as its limitations, are being analyzed. Simulation and experimental results are also presented to verify the mentioned relationship via investigations of system performance under different loading conditions. The research can provide a guideline for determination of HPQC operation voltage when load varies. INTRODUCTION: With rapid country and city development around the world, electric railway transportation has played an essential role in economics and daily lives. This causes high and increasing transportation demand. It is therefore important that traction power supply is stable and can provide power with high power quality to locomotives. However, traction power supply usually suffers from various power quality problems such as reactive power, system unbalance and harmonics, etc. Various power quality compensation techniques, which are discussed in later sections, are therefore proposed. The key concept of the capacitive current balancing methods is the use of blocking capacitor,. A series connected blocking capacitor in the secondary side of the transformer balances the current of two LED strings. By the charge conservation, the average current flows through the two LED strings (Avg(iLED1) and Avg(iLED2) are naturally balanced without the active components. The capacitive method is very cost-effective in that it uses small number of components. In the primary side of the passive current balancing drivers, a current source type inverter is required in order to use the charge balance of the blocking capacitor. LLC converter is widely used because of its zero voltage switching characteristics. However, the LLC converter requires two main switches and the additional resonant inductor to obtain wide output voltage range. Therefore, the passive current balancing drivers that use the LLC converter have a limitation in their system volume and cost. EXISTING SYSTEM: In traditional AC traction power supply, the power in three phase grid is transformed into two single phase outputs through substation and supply power to locomotives. Since the two single phase power is of different phase, neutral sections (without power supply) are required to avoid risk of phase mixing. As locomotives run through neutral sections, they lose power and velocity. Traditional AC power structure is therefore not suitable for high-speed railway. It is basically composed of a back to back converter with a common DC link. One converter, or instance, the Vac phase converter is connected to the locomotive phase through inductive coupled impedance; and another phase, Vbc phase converter, is connected to the unloaded phase through inductive coupled impedance. In order to control the power flow so as to achieve power quality compensation, the energy of the DC link must be higher than the point of common coupling (PCC) point. In other words, the DC link voltage must be higher than the peak of Vac voltage. BLOCK DIAGRAM: INDUCTIVE LOAD FILTER CONVERTER 2 12V DC 5V DC FILTER ENERGY STORAGE DRIVER CIRUIT PIC CONTROLLER WITH BUFFER CONVERTER 1 PROPOSED SYSTEM: In co-phase traction power locomotive loadings are connected across one single phase output of substation transformer only, leaving another phase unloaded. This proposed structure is beneficial for effective reduction of neutral sections and higher transformer utilization ratio. The co-phase structure is thus more suitable for application in high-speed railway. Hybrid railway power quality conditioner (HPQC) is thus proposed and developed. Different from traditional RPC, the Vac phase converter in HPQC is connected to the PCC through capacitive coupled impedance ADVANTAGES: The capacitive coupled capacitance can help to provide support voltage during reactive power compensation so that the DC link voltage can be decreased. The device rating and cost of HPQC can thus be reduced TOOLS AND SOFTWARE USED: MPLAB – microcontroller programming. ORCAD – circuit layout. MATLAB/Simulink – Simulation APPLICATIONS: Electric railway transportation CONCLUSION: In this paper, the relationship between HPQC DC link voltage and its power quality compensation capability in co-phase traction power is being analyzed and discussed. Co-phase traction power has high potential to be power supply system. However, the operation voltage requirement of conventional inductive coupled RPC within the system is high due to its high power requirement to control power flow. This leads to higher cost and device ratings. The capacitive coupled HPQC is therefore newly proposed for reduction of operation voltage while providing similar performance at rated load. Nevertheless, reduction in HPQC operation voltage limits its power quality compensation capability. Therefore, it is essential to determine the relationship between HPQC DC operation voltage and the corresponding power quality compensation capability so as to provide a guideline for the design of HPQC. REFERENCES: [1] Amrutha Paul, P. ; Anju, U.D. ; Anoop, M.P. ; RajanPallan, M. ; Roshna, N.K. ; Sunny, A., “Effects of two phase traction loading on a three phase power transformer”, in Annual International Conference on Emerging Research Areas: Magnetics, Machines and Drives, AICERA/iCMMD, 2014, pp. 1-5. [2] Joseph, V.P. ; Thomas, J., “Power quality improvement of AC railway traction using railway static power conditioner a comparative study”, in International Conference on Power Signals Control and Computations , EPSCICON, 2014, pp. 1-6. [3] Gunavardhini, N. ; Chandrasekaran, M. ; Sharmeela, C. ; Manohar, K., “A case study on Power Quality issues in the Indian Railway traction sub-station” in 7th International Conference onIntelligent Systems and Control, ISCO, 2013, pp. 7-12