Characteristics Of Power Supply Research Articles

Determination of Diagnostic Parameters of Power Plants Based on Internal Combustion Engines

Abstract The presented article shows a method for finding monitored parameters for creating a diagnostic system for autonomous power sources based on spark ignition engines and diesel engines. The classification of structures of autonomous power sources based on internal combustion engines has been carried out. The analysis of the design features of the most common back-up power sources on the market based on internal combustion engines (ICE) indicates the widespread use of generators with a synchronous alternator. The analysis of the design features of autonomous power supplies has made it possible to develop logical models for different designs. The influence of the occurrence of a faulty state of each element on other elements of the systems is analyzed, and the results of the analysis are summarized in tables. An informative Claude Chenon criterion is proposed for finding the optimal number of diagnostic parameters among an infinite number of possible combinations of physical parameters that characterize the system. When solving the problem, a hypothesis was proposed about the equiprobability of cases of exit from the working state of each of the elements of the system. The use of Claude Chenon allows you to find the parts that make up the generators, which with maximum efficiency reduce the degree of uncertainty in the system. After determining the residual entropy, the parts of the system are selected, the state of which should be monitored by the diagnostic system. For such parts of the system, diagnostic parameters are found and methods for obtaining them are indicated.

New Principle of Pilot Protection Based on Kendall’s Rank Correlation Coefficient

Affected by the control strategy after MMC failure, the fault current on the converter side of the AC line interconnected with the MMC is significantly different from the fault characteristics of the traditional power supply in amplitude and phase. The new fault current characteristics lead to the inapplicability of the traditional longitudinal current phase differential protection. In order to solve the problem of the applicability of relay protection, a new principle of longitudinal protection based on Kendall’s rank correlation coefficient is proposed. After the AC line fails, the Kendall grade correlation coefficient of the calculated current on both sides is calculated to distinguish the internal and external faults. Simulations are carried out on the RTDS platform, and the results show that the proposed protection principle can reliably distinguish between internal and external faults and has the ability to withstand transition resistance under various control reference values.

Analysis of Fault Characteristics of AC Line Interconnected with MMC

Affected by the control strategy of suppressing the negative sequence current and limiting the amplitude of the positive sequence current after the MMC fault, the fault characteristics of the converter side of the AC line interconnected with the MMC show that the negative sequence current is very small and the positive sequence current amplitude is different from the rated value Compared with the fault characteristics of the traditional power supply, there are obvious differences between the minor characteristics and the fault characteristics of the traditional power supply. And it has been simulated and verified on the RTDS simulation platform.

Within-day rolling optimal scheduling problem for active distribution networks by multi-objective evolutionary algorithm based on decomposition integrating with thought of simulated annealing

The prediction accuracy plays a very important role in the optimal dispatch problem of active distribution networks (ADN). Basing on the fact that the prediction accuracy will be greatly improved when approaching prediction domains and decreasing prediction time periods, rolling optimization provides an alternative approach to handle uncertainty of renewable sources in ADN. Considering the characteristics of power supplies and loads in ADN, a comprehensive model of rolling multi-objective optimal dispatch is established. Four objective functions of minimizing the ADN operation cost, minimizing adjustment of the active power outputs to the day-ahead plan, minimizing the total active power loss, and minimizing the total voltage deviation of the system are considered simultaneously. Then, the thought of simulated annealing is integrated into the multi-objective evolutionary algorithm based on decomposition (MOEA/D) to change the process of generating new solutions and the neighborhood updating process. Therefore, the proposed MOEA/D with the thought of simulated annealing (MOEA/D-TSA) is adopted to solve this rolling multi-objective optimal dispatch problem. In the proposed approach, a dynamic probability value is employed to select which neighbor subproblem should be updated using the new generated solution in order to balance global and local searching ability of the algorithm. Finally, the performance of the proposed approach is tested and verified on an improved IEEE 33 node test system. The comparisons of the proposed method with the original MOEA/D and NSGA II on non-dominated solutions, extreme solutions, optimal compromise solution (OCS) and statistical indicators are well illustrated. The results show that MOEA/D-TSA algorithm has better convergence and comprehensive performance than other considered algorithms and its application in rolling dispatch problem is also presented through this test system.

Features of Power Supply and Distribution Plans in Hotel

Features of Power Supply and Distribution Plans in Hotel

Energy characteristics of combined power supplies with supercapacitors and lithium-ion batteries

Energy characteristics of combined power supplies with supercapacitors and lithium-ion batteries

Using the constant current ‒ constant voltage converters to effectively reduce voltage fluctuations in the power supply systems for electric arc furnaces

AC electric arc furnaces (EAFs) are among the most common technological units for making high-quality steel. The use of furnaces is promising in the future as the production volumes of electric steel increase. These furnaces are powerful electrical installations exposed to the dynamic, asymmetrical, and nonlinear load, which adversely affects the quality indicators of electricity supply. Typically, this negative impact is reduced by connecting EAFs to high power energy systems or, in most cases, by applying different types of static reactive power compensators. Such approaches require considerable investment in the development of the power system or in the equipment of compensatory installations whose rated capacity is several times higher than the capacity of the furnace transformer. These approaches aim to reduce the effects of negative impact. It is possible to achieve the greater effect of limiting the negative impact, at smaller investments, by using an alternative approach that aims directly at the source of the negative impact. The approach implementation implies forming an external characteristic of the EAF power supply. The characteristic should be rigid in current in the region of furnace operating modes from operational short circuit to the rated load. In the region of modes from the rated load to idling, this characteristic should be rigid in voltage. Underlying the formation of this characteristic is a resonance converter, which ensures almost a stable value of the arc current under the furnace operating modes. This study has confirmed the significant benefits of the proposed approach, which proves more effective in improving the quality of electricity in the network. This makes it possible to use EAFs in smaller power systems and ensure the development of the industry at a lower investment

Design and characteristics of a modular integrated power supply for the system of flashlamp-pumped in inertial confinement fusion

• A 1.46 MJ capacitive pulsed power supply is designed by using the pulse thyristors. • The synchronous triggering of multiple sets of thyristors enables high current output of the pulsed power supply. • The high gate trigger system is developed to control the synchronous conduction of the thyristors of each module. • Simulation and project experience show that the high-probability failure will not affect the other components in the power supply. In order to study the adaptation of the semiconductors for the special power supply application, a capacitive pulsed power supply is designed by using the pulse thyristors. The modular integrated method is adopted to redesign the main circuit of the power supply. The synchronous triggering of multiple sets of thyristors enables high current output of the pulsed power supply, which can avoid excessive current passing through the thyristors and eliminate current-sharing measures of the thyristors. Applying the fast switching MOSFET and magnetic induction of pulse transformer, a set of high gate trigger system is developed to control the synchronous conduction of the thyristors of each module. The simulation and experimental results show that most of the faults occurring during the operation of the pulsed power supply can be limited by protection devices. Practical operation indicates that the pulse power supply can provide specific required pulse current and energy for the pulsed xenon lamp. The design method of the pulsed power supply can provide a reference for the design of the pulsed power supply, and lay a foundation for the higher capacitive energy storage application.

Research on the machining characteristics of composite pulse power supply for the electrical discharge machining of semiconductor silicon crystal

Aiming at the problem of low efficiency in cutting silicon crystals with traditional wire electrical discharge machining (wire EDM) equipment, this paper proposes a method to improve the efficiency of electrical discharge cutting for silicon crystals by using composite pulse power to process semiconductors. This paper established a wire EDM equivalent circuit model, analyzed the magnitude of the discharge sustaining voltage on metal and semiconductor in wire EDM, studied the current-voltage characteristics of silicon crystals under a composite power supply, and compared the machining performance with and without the new power supply. The experiments show that, compared with the single power supply, the composite power supply can increase the machining current, and the existence of its high-voltage module can increase the probability of forming the discharge channel, which is convenient for wire EDM; using this power supply, the traditional servo system based on voltage detection can be used to distinguish the three typical machining states (short circuit, normal discharge, and no-load) in wire EDM for semiconductor machining, realize an effective servo feed, and improve machining stability; compared with the single power supply with an open voltage of 80 V, the new power supply with an open voltage of 80 V for the low-voltage module and 120 V for the high-voltage module has a certain increase in surface roughness, the processing efficiency is increased by 75%, and the kerf width is increased by 3.4%.

Induction heat treatment of large rolls with two independent power sources

The two-inductor heat treatment system for rolls of rolling mills is highly flexible and can improve the quality of heat treatment while solving energy-efficiency and productivity problems. A digital model of induction heat treatment of rolls with the computation of electromagnetic, temperature and stress fields is developed taking into account the characteristics of power supplies and control systems for heat treatment modes. Particular attention is paid to the reliability of frequency converters in the presence of magnetic coupling between inductors. Recommendations on frequency selection and inverter settings are given. A universal method of digital design and control of thermal conditions in induction heat treatment systems is considered.

Implementation and design of the control system for poloidal field power supply

• Three layers of subsystems are constructed for the control system of EAST poloidal field power supply. • Architecture based on real-time system and high speed communication network is proposed to make control loops on power supply controllers running at strict cycle-time. • Handy human-machine interface and sensitive alarming mechanism based on EPICS are achieved to monitor the power system. • Unified external clock and external trigger scheme are developed to enhance the data acquisition management system. This paper introduces the architecture and characteristics of the poloidal field power supply, and describes the architecture of its control system, which is composed of data acquisition management system, operation monitoring system and real-time control system. According to the characteristics of the control system, a data acquisition management system based on Qt, an operation monitoring system based on EPICS and the real-time control system is based on Linux real-time kernel are designed. The control system realizes real-time control of EAST poloidal field power supply system in 1 ms cycle time, and the equipment status detection and monitoring, data acquisition, storage and inspection. Several experiments have proved that the control system definitely meets the requirements of the poloidal field power supply control system in the complex situations under magnetic fields.

Multi-objective configuration optimization method for a diesel-based hybrid energy system

In this paper, a configuration optimization method for a diesel hybrid energy system has been proposed. The method is based on a fuzzy artificial bee colony optimization mechanism that considers the power supply characteristics of an isolated hybrid energy system. First, a mathematical model based on a diesel hybrid energy system and a configuration optimization objective function that considers cost and load shortages is constructed. Then, an objective function is optimized in combination with fuzzy rules and artificial swarming algorithms to obtain a system configuration that meets multiple objective requirements. Finally, the system configurations of three hybrid modes of photovoltaic (PV)/energy storage/diesel, wind power/energy storage/diesel, and PV/wind power/energy storage/diesel are compared, and the pollutant emissions of the different systems are analyzed. Experimental results show that the new method exhibits good configuration optimization and performance, and it is a practical approach for solving the problem of microgrid system configuration.

Fast Distributed Voltage Control for PV Generation Clusters Based on Approximate Newton Method

Solar power generation is exhibiting a distributed development trend, and has changed conventional characteristics of power supply and consumption. The integration of large-scale distributed photovoltaic (PV) generation forms high-penetration PV clusters in distribution networks, which aims to organize and control geographically scattered resources. However, due to the inherent uncertainty, high-penetration PV clusters are suffering from random disturbances and serious voltage risks. Besides, integrating system via power electronic interfaces, PV generation usually tracks system frequency without any backup and regulation capacity, which poses significant challenges to system operation, and requires greater flexibility of voltage control. In fact, by using appropriate methods, PV inverters can autonomously regulate reactive power output in a distributed manner to improve voltage profiles in clusters. In this article, a distributed voltage control method for PV generation clusters is presented to realize decentralized coordination of PV inverters. Based on matrix splitting and approximate Newton method, it can fast respond to reactive power mismatch and realize voltage profiles optimization. Exhibiting a more efficient, reliable and flexible performance than existing decentralized methods in case studies, the proposed method is demonstrated to effectively organize and control PV cluster to provide corresponding reactive power support and exert friendly effect on system operation.

Optimal configuration of battery energy storage system with multiple types of batteries based on supply-demand characteristics

Abstract The configuration of a battery energy storage system (BESS) is intensively dependent upon the characteristics of the renewable energy supply and the loads demand in a hybrid power system (HPS). In this work, a mixed integer nonlinear programming (MINLP) model was proposed to optimize the configuration of the BESS with multiple types of batteries based on the power supply and demand characteristics. A three-step solving strategy was developed to improve the computational efficiency by transforming the MINLP model into a mixed integer linear programming (MILP) model. The effectiveness of the proposed model and the solution strategy were demonstrated through a case study. Results showed that the optimal capacity configuration of the BESS with multiple types of batteries can be obtained by the proposed model and the three-step solving strategy. And the computation time of the proposed solution strategy is over 100 times shorter than that of the conventional solution method for solving the configuration problems of the BESS with multiple types of batteries at a large-scale. The superiority of each type of battery over others depends upon the electricity price in different scenarios. In addition, the selections of battery types and their capacities are dramatically influenced by the amplitude and the period of the power difference curves.

Substantiation of diagnostic parameters of autonomous sources of electric energy on the basis of the internal combustion engine at development of system of technical diagnostics


 
 
 The paper presents a method for selecting diagnostic parameters for creating a system for diagnosing autonomous sources of electricity based on an internal combustion engine (ICE). A literary search for autonomous sources of electricity was conducted. The expediency of using internal combustion engines as autonomous sources of electric energy is determined. The analysis of design features of the most widespread in the market of Ukraine reserve sources of electric energy on the basis of internal combustion engines is carried out. The analysis of the
 
 
 
 design features of autonomous power supplies allowed a developing of a logical model of the object of study. The developed logical scheme of the research allows to establish the relationship between the main structural elements of the system, as well as to determine the possible states of the system. The consequences of the occurrence of a faulty state of each element on the other elements of the system are analyzed, and the results of the analysis are summarized in the table. An informative criterion is proposed to determine the finite number of diagnostic parameters among the infinite number of possible combinations of physical parameters that characterize the system. The concept of information entropy of K. Shannon is offered as an informative criterion. Equally probable cases of exit from the working condition of each of the elements of the system are considered. Applying the concept of Shannon's information entropy, the residual entropies of the system at the faulty state of one of the nodes of the autonomous power supply are determined. The criterion of informativeness is the value of residual entropy. The application of this criterion allowed determine of the elements of the system that most effectively reduce the degree of uncertainty of the system. The element of the system that has the lowest residual entropy has the maximum effect on the state of the autonomous power source based on the internal combustion engine. Based on the values of residual entropy, the nodes of the system are selected, the state of which should be primarily monitored by the diagnostic system. For such elements diagnostic parameters are defined, and ways of their reception are resulted.
 
 
 
 
 

Analysis on the Influence of Breech Voltage on the Pulsed Discharge Characteristics of Capacitive Pulsed Power Supply in EML

Corresponding to the different gradient of the ideal working current, the movement process of the armature in the railgun bore can be divided into rising phase, stable phase and decreasing phase. Based on the load characteristic and the lumped-element equivalent circuit of the railgun, the characteristics of the railgun’s breech voltage in above three phases were analysed. Under the condition that the size of the launching system is close to the same, the change ranges of the breech voltage of the augmented railgun is much larger than that of the simple railgun, and the breech voltage of the augmented railgun is a very high forward voltage in the rising phase. The influence of the breech voltage on the discharge characteristics of the capacitive pulsed power supply was studied. In the rising phase, the high breech voltage of the augmented railgun has a significant adverse effect on the pulsed discharge characteristics of the capacitive pulsed power supply whose pulsed forming net consists of a large number of pulsed forming units with small energy storage and high resonance frequency. As a result, part of the stored energy of the capacitive pulsed power supply cannot be used effectively, which leads to the decrease of the working efficiency of the launching system. Using the launching system with a 13-MJ capacitive pulsed power supply and a medium calibre augmented railgun, the launching simulation and test were completed, and the analysis was verified. The research has important enlightenment for improving the match between the capacitive pulsed power supply and the railgun.

A new approach for analyzing the effect of non-ideal power supply on a constant current underwater cabled system

The effect of a constant current (CC) power supply on the CC ocean observation system is a problem that once was neglected. The dynamic characteristics of the CC power supply may have great influence on the whole system, especially the voltage behavior in the event of load change. This needs to be examined. In this paper, a method is introduced to check whether the CC power supply can satisfy the dynamic requirements of the CC ocean observation system. An equivalent model to describe the non-ideal CC power supply is presented, through which the dynamic characteristics can be standardized. To verify the feasibility of this model, a minimum system of a single node in the CC ocean observation system is constructed, from which the model is derived. Focusing on the power failure problem, the output voltage responses are performed and the models are validated. Through the model, the dynamic behavior of the CC power supply is checked in a practical design.

ЭЛЕКТРОСНАБЖЕНИЕ ЦЕХА С ПОДЪЕМНО-ТРАНСПОРТНЫМ ОБОРУДОВАНИЕМ

the features of power supply of hoisting-and-transport equipment are considered,
 ways of supply of the electric power for mobile electroinstallation are defined, the variant of modernization of the crane electric drive with application of the frequency converter is offered.

Data-Driven Abnormity Assessment for Low-Voltage Power Consumption and Supplies Based on CRITIC and Improved Radar Chart Algorithms

With the wide deployment of advancing metering infrastructure (AMI) in power distribution systems, the quantity of power consumers’ electricity data is increasing rapidly and the data also become more and more accurate. To make full use of these power consumers’ AMI data, a data-driven abnormity assessment algorithm for low-voltage power consumers is proposed based on the CRITIC (CRiteria Importance Though Intercrieria Correlation) method and the improved radar chart method. First, the indexes that characterize the consumer’s abnormal features of power consumption and supplies are extracted from the original AMI data. Then, the abnormity assessment algorithm is used to determine power consumers’ abnormal features of power consumption and supplies by using the extracted indexes, in which the weights of indexes are determined by the CRITIC method and the assessment value of abnormal features is determined by the improved radar chart method. Next, the abnormity assessment algorithm is used again to assess power consumers’ power consumption and supplies abnormities. Finally, the effectiveness of proposed algorithm is demonstrated in case studies by employing AMI data collected from power utilities in Zhejiang Province, China, and the results show that the algorithm can be used in actual applications.

Multi-Mode Switching Control of the EPS With Hybrid Power Supply

Electric power steering system (EPS) with traditional power supply can't provide enough power for heavy-duty vehicle to turn at low speed. To solve the problem, a novel EPS with hybrid power supply was constructed. In this paper, firstly, mathematical model of the EPS with hybrid power supply was established including model of hybrid power supply system and basic model of EPS. Then the power mode recognition was obtained according to the certain threshold of steering resistance torque, state of charge (SOC) of super-capacitor and output voltage of the vehicle power supply, and the corresponding finite automaton model was built. The EPS system with hybrid power supply was regarded as a hybrid system due to continuous event in a single mode and discrete event during mode switching process, thus the multi-mode switching control strategy was proposed. Taken the different characteristics of hybrid power supply in different power modes into account, the corresponding local controllers were designed which were consisted of fuzzy-PID controller, active disturbance rejection controller (ADRC) and sliding mode controller. Besides, the fuzzy supervisory controller was also designed to ensure the stability of the hybrid system during mode switching process. The simulation results show that the local controllers can achieve fast and accurate track of target current in each power mode, and the fuzzy supervisor can effectively ensure the stability of the switching process, which demonstrates the feasibility of the control strategy.