Low Voltage Power Supply System Research Articles

On load voltage regulating device of long-distance mine low-voltage power supply system based on solid-state voltage regulator

In order to solve the problem of voltage loss caused by long-distance power supply system, considering the solid state power boost (SSPB) of solid-state voltage regulator, this paper proposes an on load voltage regulating device for long-distance mine low-voltage power supply system based on solid-state voltage regulator, which aims to solve the problem of voltage loss and fluctuation caused by line voltage drop and coal mining equipment startup and shutdown. Firstly, the terminal voltage of the line is deduced through the mathematical model of the motor under different working conditions, and a terminal voltage prediction algorithm is proposed, which calculates the terminal voltage state according to the electrical parameters at the head side of the substation; Then, an on load voltage regulation technology based on solid-state voltage regulator is designed and implemented, which compensates by controlling the output voltage of the inverter in series into the first end of the line. When the motor is in rated operation and start-up and stop stages, the motor voltage operates within a reasonable range; Finally, the simulation model of on load voltage regulation technology is built by using MATLAB/SIMULINK software, and the feasibility of this technology is verified by different experimental settings.

99%, 15W/cm<sup>3</sup> Capacitively Coupled Modular DCPET for Low-Voltage DC Power Supply Systems

99%, 15W/cm<sup>3</sup> Capacitively Coupled Modular DCPET for Low-Voltage DC Power Supply Systems

A leakage protection method for low-voltage power supply systems based on flexible regulation of the neutral point voltage

Low-voltage power supply systems, which are very prone to leakage faults, are deep in the customer terminal, and the operation environment is complex. The traditional leakage protection devices applied in TN-S systems cannot isolate single-phase leakage faults while maintaining power supply. Thus, a leakage protection method based on flexible regulation of the neutral point voltage for a low-voltage power supply system is proposed. By extracting the potential of the fault phase, using a single-phase regulating transformer to reverse the voltage applied between the zero line and the protection ground line, and adjusting the ratio of the single-phase regulating transformer to regulate the fault phase to ground voltage, the fault phase to ground voltage is suppressed to 0 V and the leakage fault residual current is eliminated. In the PSCAD/EMTDC simulation environment and in a 10 kV real-type distribution network laboratory, a TN-S system model was built to simulate various fault conditions. The simulation and experimental test results show that the method can actively isolate single-phase leakage faults and eliminate potential leakage problems without affecting the power supply of users.

Study on Selective Insulation On-line Monitoring Technology for Mine Power Network

In this paper, by studying the change rule of zero sequence voltage when single-phase leakage occurs, the detection method of insulation decline of mine cables is studied, especially the additional low-frequency signal sampling technology of power cables. Combined with the conventional leakage protection technology, the online monitoring equipment and supporting software for the insulation parameters of power cables are developed to realize the online monitoring of the insulation of each branch cable of the mine low-voltage power supply system and achieve the purpose of selective leakage protection.

Energy Minimization in City Electric Vehicle using Optimized Multi-Speed Transmission

This article discusses a set of solutions for creating a city electric car with a low-voltage power supply system for a DC motor. Based on a constructed city vehicle with a low voltage electric drive system, a simulation model was prepared and verified. An energy flow analysis was performed, and the developed simulation model was described. Then, the optimization method was focused on minimizing the energy consumption of the vehicle in the driving cycles under consideration. To mirror the actual road conditions as much as possible, the real traffic cycle registered over an actual route was used in the process of optimization, with the cycle’s velocity profile and recording of the road slope angle used in the simulation program. Established optimality quantitative dependence of the design and control parameters of the gearbox on the operational characteristics of the electric vehicle, which allowed for the determination of parametric and functional limitations during optimization. As a result of employing the described design solutions and optimization of drivetrain parameters, an over 40% reduction in the vehicle’s energy consumption in a real driving cycle test was obtained.

Bi-directional buck-boost voltage converter for low-voltage uninterruptible power supply systems

Bi-directional buck-boost voltage converter for low-voltage uninterruptible power supply systems

A Decomposition Four-Component Model for Calculating Power Losses in Low-Voltage Power Supply Systems

A new model for decomposition of the total power losses, which includes four components is proposed. Each of the components of the proposed model has a certain physical meaning due to the nature of electromagnetic processes in a three-phase four-wire system. Definitions to describe each of the proposed components are formulated. It is shown that each of supplementary components of the total loss power is proportional to the minimum possible loss power and to the square of the RMS value of the power, which is caused by its occurrence in three-phase four-wire power supply system, and it is inversely proportional to the mean square of the net power loss. The synthesized Matlab-model for verification of the four-component structure of power losses showed a high degree of its adequacy. The proposed model allows us to rethink the description of power losses in three-phase AC circuits and can be used in specialized measuring instruments for electrical networks monitoring. Using the information obtained in the monitoring process, it is possible to plan technical measures to reduce losses of electrical energy in the power supply system, as well as to estimate the capital costs of these measures.

A review of exploratory studies at RSC Energia into high-temperature voltage conversion systems for an electrically-propelled transportation spacecraft

The paper presents studies conducted at RSC Energia that looked into the feasibility of developing a high-temperature high-power voltage converter of a low-voltage space power supply system for an electrically-propelled space transportation spacecraft based on classical voltage conversion systems using electroplasma gates (key elements) and high-temperature transformers. It provides electrical schematics fro voltage conversion systems. It presents results of experimental studies on lab prototypes of electroplasma gates with electrical power of tens and hundreds kilowatts, which have demonstrated that in principle it is possible to use them as a basis for development of high-temperature radiation-proof voltage converters with mass fraction of ~0.01 kg/A for such power sources as nuclear power-supply systems with sub-megawatt and megawatt thermionic converter reactor. It provides a rationale for selecting the voltage conversion frequency in systems without forced cooling. It provides an experimental proof that in principle it is possible to implement high-temperature transformers with 600°С operating temperature level, and gives recommendations on selection of materials. Key words: space power system, electrically-propelled transportation spacecraft, voltage converter, electroplasma gate, high-temperature transformer, conversion frequency.

Evaluation of the Efficiency of Already Existing Network Solar Photovoltaic Plants Operating 24/7/365 in Low-Voltage Power Supply Systems of Social Facilities in the City of Dushanbe

Evaluation of the Efficiency of Already Existing Network Solar Photovoltaic Plants Operating 24/7/365 in Low-Voltage Power Supply Systems of Social Facilities in the City of Dushanbe

A review of exploratory studies at RSC Energia into high-temperature voltage conversion systems for an electrically-propelled transportation spacecraft

The paper presents studies conducted at RSC Energia that looked into the feasibility of developing a high-temperature high-power voltage converter of a low-voltage space power supply system for an electrically-propelled space transportation spacecraft based on classical voltage conversion systems using electroplasma gates (key elements) and high-temperature transformers. It provides electrical schematics fro voltage conversion systems. It presents results of experimental studies on lab prototypes of electroplasma gates with electrical power of tens and hundreds kilowatts, which have demonstrated that in principle it is possible to use them as a basis for development of high-temperature radiation-proof voltage converters with mass fraction of ~0.01 kg/A for such power sources as nuclear power-supply systems with sub-megawatt and megawatt thermionic converter reactor. It provides a rationale for selecting the voltage conversion frequency in systems without forced cooling. It provides an experimental proof that in principle it is possible to implement high-temperature transformers with 600°С operating temperature level, and gives recommendations on selection of materials. Key words: Space power system, electrically-propelled transportation spacecraft, voltage converter, electroplasma gate, high-temperature transformer, conversion frequency.

Discussion on Grounding Mode of Low Voltage Power Supply and Distribution System

Discussion on Grounding Mode of Low Voltage Power Supply and Distribution System

Учет структурных особенностей управляемых батарей статических конденсаторов при определении эффекта энергосбережения от их использования в низковольтных системах электроснабжения промышленных предприятий

Учет структурных особенностей управляемых батарей статических конденсаторов при определении эффекта энергосбережения от их использования в низковольтных системах электроснабжения промышленных предприятий

Low-voltage power supply system based on three-phase to two-phase and integrated power quality control method

The two-input single-phase transformer is widely used in the 10kV power distribution system. However, this power supply mode has the disadvantage of the 10kV side three-phase unbalance problem. In response to this problem, the paper proposes a new 220V single-phase low-voltage power supply system based on a three-input single-phase transformer. The power supply system consists of a three-phase transformer and a two-phase transformer and a phase-to-phase power controller. The three-phase to two-phase transformer is used to realize two low-voltage single-phase power supply, and the phase-to-phase power controller is used to realize the negative sequence and harmonic control of the low voltage side. This power supply mode is suitable for large-capacity low-voltage power supply systems with single-phase load intensive. The paper analyzes the transformation theory and control strategy of the power supply mode. Finally, the superiority and effectiveness of the proposed technical scheme and control strategy are verified by simulation analysis.

On Optimization of a Power-Supply System of a Magneto-Plasma Compressor

The operation of a miniature magneto-plasma compressor with low-voltage power-supply system was studied experimentally and the current and voltage drop under discharge were measured. It was found that the voltage drop remains practically constant during discharge and amounts to a few tens of volts. The performed electrotechnical analysis made it possible to determine the efficiency of the power-supply system depending on the initial voltage of the energy storage, the discharge burning voltage and the discharge circuit parameters (capacitance, inductance, and resistance).

Study on the Transient Process of 500kV Substations Secondary Equipment

By analyzing on the reason of the lightning accident occur in the substation, the way of lightning incoming surge invading the secondary system is summarized. The interference source acts on the secondary system through various coupling paths. It mainly consists of four ways: the conductance coupling mode, the Capacitive Coupling Mode, the inductive coupling mode, The Radiation Interference Model. Then simulated the way with the program-ATP. At last, from the three aspects of low-voltage power supply system, the impact potential distribution of grounding grid, the secondary system and the computer system. The lightning protection measures is put forward.

Load Characteristics in Low Voltage DC Power Supply Systems

Low voltage direct current (LVDC) power supply systems have brought new growing point to low voltage power supply systems due to the high efficiency, improved reliability and power quality. In order to realize the extensive advancement of LVDC power supply systems, it is necessary to discuss several issues on the load side in LVDC systems, to reflect the advantages of LVDC systems on the load side. Based on the above purpose, this paper compares the electrical efficiency, power quality and reliability of load side between LVDC and traditional AC power supply systems, analyzes the compatibility of existing load in LVDC systems and finally, summarizes the load operating characteristics and load model in the LVDC systems. The research shows feasibility and superiority for the existing load when supplying from LVDC systems.

Effect of Distributed Photovoltaic Generation on the Voltage Magnitude in a Self-Contained Power Supply System

A promising way to increase the technical and economic characteristics of standalone power supply systems is to incorporate renewable energy installations in their structure. This saves fuel and extends the operational life of diesel power stations. The most common option is a hybrid system with photovoltaic power stations incorporated into the local network of the diesel power station. This paper deals with the dependence of the deflection voltage and power losses in the electric power transmission line on the graphs of electrical loads, the parameters of elements of the power supply system, connection points and the capacity of distributed photovoltaic power stations. Research has been carried out on the common low-voltage power supply systems of the radial type (0.4 kV) with an installed capacity of up to 100 kW. The studies have been conducted by simulating the operating modes of hybrid power systems of various configurations. As a result of these studies recommendations to reduce losses and voltage variations in the network by selecting the power and photovoltaic power connection points have been put forward.

Short-Circuit Current Criterion under Condition of Protection Action in Low Voltage Power Supply System

In order to improve the level of automation and security of the low voltage power supply system, this paper proposed the calculation method of short-circuit current criterion under condition of protection action. Firstly, the impact of circuit breakers on the short-circuit current is analyzed. Then, the current criterion under condition of short-circuit protection are given. Finally, using a special case, the calculation process of aforementioned current criterion is given in detail.

The Principle Analysis and Research of Power System Converter of Microwave Power Module

According to the demands of power supply system of microwave power module (MPM), ZVS push-pull dual-voltage resonant converter is present. High-voltage can be achieved in this new novel converter topology. The paper introduces the structure of the converter. Then the steady-state and operation characteristic of the converter is analyzed and deduced. A Pspice simulation is carried out to verify the theoretical analysis, the results and conclusions are given in the end. The results show that the ZVS push-pull dual-voltage resonant converter can realize the soft-switch and double voltage well. The structure of the converter is simple and easy to implementation, so it suitable for low input voltage and high output voltage power supply system.

Open Press Electrical Accident Risk Assessment based on Bayesian Network

Since multiple state events could not be described and accident probability could not be calculated by fault tree quantitatively for safety assessment, applications of Bayesian network (BN) in safety and reliability fields for the past few years were introduced and basic principle and inference algorithm of Bayesian network were presented. A Bayesian network was developed to model open press electric shock accident as a result of charged press enclosure. The multi-state nodes of the network were illustrated and accident probability was computed finally. The results show that Residual Current Operated Circuit-Breaker with Integral Overcurrent Protection (RCBO) installation can reduce accidents probability of phase-voltage and under-phase-voltage electric shock sharply for open press working in T - T system of low voltage power supply system. In a word, Bayesian network can model system which contains multiple state events, furthermore, accidents probability of that system can be computed correctly, in addition, it offers a comparative tool for various safety design of machine system to guarantee machine inherent safety.