scholarly journals Development of universal algorithm of voltage circuits detecting faults of microprocessor protection and automation devices

Vestnik IGEU ◽  
2021 ◽  
pp. 33-41
Author(s):  
V.Yu. Vukolov ◽  
A.A. Petrov ◽  
S.N. Yurtaev ◽  
R.Sh. Bedretdinov
Keyword(s):  
Complex Plane ◽  
Failure Modes ◽  
Relay Protection ◽  
Response Speed ◽  
Input Voltage ◽  
Voltage Transformer ◽  
Electric Line ◽  
Sensitivity And Selectivity ◽  
Zero Sequence ◽  
Voltage Spike

Reliability, along with response speed, sensitivity, and selectivity, is the key requirement for relay protection (RP) devices. The reliability of modern RP digital terminals is understood as protection operation for all estimated failure modes and failure of protection equipment to operate in all other modes, in which this protection is not provided. Analysis of the secondary voltage schemes and algorithms of detecting faults in these circuits reveals several disadvantages of the implementation of blocking in case of faults in voltage circuits. All existing algorithms and blocking schemes in case of faults in voltage circuits suffer from several disadvantages. In this regard, it is relevant to develop a universal relay protection terminal, which can be used with any types of voltage transformers. The MatLAB Simulink is used to simulate the primary failure of secondary circuits for the connection schemes of the voltage transformer load on phase and electric line voltages. The authors propose the algorithm that allows us to create a typical universal RP terminal, which can be used with any type of voltage transformers. To detect the neutral conductor interruption of the «star» circuits, it is proposed to create an artificial asymmetry at the input voltage circuits of the relay protection and automation (RPA) terminal and develop a group of fault detectors that analyze the position of the offset neutral on the voltage complex plane. Using a simulation model of various types of failure of voltage transformer secondary circuits and the logic diagram of the unit that implements the proposed algorithm, the authors graphically show that the detection of a break in the neutral wire is possible due to monitoring the zero-sequence voltage spike (triggering of the pulsed dU0 fault detector) with neutral displacement to the complex plane area, which is set by the setpoints. The results obtained allow us to implement a universal scheme of blocking faults in voltage circuits. This scheme does not depend on the voltage transformer secondary load connection method and exclude the disadvantages of existing solutions discussed in the article. This algorithm allows us to develop a typical universal RPA terminal. Due to its connection scheme and functional and logical implementation, this terminal can be used with any types of voltage transformer without reprogramming. Also, the proposed algorithm fully complies with the requirements of the current regulatory and legal documents.

Development of Serial-Connected High Step-Up DC-DC Converter with Single Switch

2013 ◽  
Vol 479-480 ◽  
pp. 535-539
Author(s):  
Van Tsai Liu ◽  
Chien Hao Hsu
Keyword(s):  
Electric Vehicles ◽  
Pulse Width Modulation ◽  
Hybrid Electric Vehicles ◽  
Single Pulse ◽  
Input Voltage ◽  
Duty Ratio ◽  
Leakage Inductance ◽  
High Voltage Gain ◽  
Output Capacitor ◽  
Voltage Spike

In this paper, a novel high step-up DC-DC converter has been designed for fuel cell applications. The proposed high step-up converter can be used for various portable energy storage components such as fuel cells which are used for hybrid electric vehicles (HEV), and light electric vehicles (LEV).The proposed converter is integrated by boost circuit, voltage lift capacitor, and coupled-inductor techniques to achieve high step-up voltage and has several advantages. First, the circuit is controlled by one single pulse width modulation (PWM). Second, the converter consists of active clamp circuit to recycle the leakage inductance and send to output capacitor so that the voltage spike on active switch is suppressed and efficiency is also improved. Third, by using the winding of secondary boost circuit, and voltage lift capacitor techniques, the high voltage gain can be achieved without more than 50% duty ratio, and the slope compensation circuit can also be simplified.Finally, a 1k W prototype converter is implemented, to verify the performance of the proposed converter with input voltage 48V, output voltage 400V, and output power 1k W is also achieved. The highest efficiency is 92.96% at 400W, and the full-load efficiency is up to 90.48%.

scholarly journals Improvement of algorithms for voltage circuits fault detection in relay protection terminal of 6-35 kV electrical networks

2019 ◽  
Vol 139 ◽  
pp. 01061
Author(s):  
Vladimir Vukolov ◽  
Mikhail Obalin ◽  
Anton Petrov
Keyword(s):  
Fault Detection ◽  
Power Supply ◽  
Relay Protection ◽  
Protection Device ◽  
Electrical Networks ◽  
Network Element ◽  
Voltage Transformer ◽  
Supply Reliability

Issues of increase of consumer power supply reliability by prevention of protection device false operation and unreasonable tripping of the protected network element at malfunction of measuring voltage transformer secondary circuits are considered. Options for implementation in relay protection microprocessor terminals of advanced blocking algorithms in case of voltage circuits fault are proposed.

Design of a Step-down DC-DC Converter ASIC Applied to Portable Electronic Products

2013 ◽  
Vol 311 ◽  
pp. 255-260
Author(s):  
Kun Fang ◽  
Yao Sheng Lu ◽  
Fei Yu
Keyword(s):  
Process Model ◽  
Current Mode ◽  
Response Speed ◽  
Input Voltage ◽  
Electronic Products ◽  
Peak Current ◽  
Voltage Range ◽  
Error Amplifier ◽  
Step Down ◽  
Battery Energy

Using CSMC 0.5μm process model, a Step-Down DC-DC converter ASIC applied to portable electronic products was designed. The peak current-mode control PWM with slope compensation was adopted in the power management chip to improve the dynamic response speed of the system; the error amplifier and PWM comparator was redesigned to improve the response speed and stability of the chip; the over-current protection function was included in the peak current sampling circuit; in addition, the circuit with the pulse-skipping mode reduce the battery energy loss. Capable of delivering 600mA Output Current over a wide input voltage range from 3.1 to 5.5V, the ASIC, that has a fixed operation frequency of 800kHz and 95% conversion efficiency, is ideally suited for portable electronic products. No external Schottky diode is required in practical application.

Design and Application of Analysis Software for Relay Protection Action Based on PAS

2014 ◽  
Vol 543-547 ◽  
pp. 766-769
Author(s):  
Nan Nan Gao ◽  
Lin Niu ◽  
Ying Pei ◽  
Hong Bo Li ◽  
Jie Zhan
Keyword(s):  
Expert System ◽  
Relay Protection ◽  
Distance Protection ◽  
Analysis Software ◽  
Regional Networks ◽  
Backup Protection ◽  
Phase Current ◽  
Three Phase ◽  
Zero Sequence ◽  
Design And Application

This paper applies the theory of expert system to analysis for relay protection action based on PAS. And it also summarizes various rules according to the experience of operating personals and relay protection personals for several years. All these rules are suitable for 110kV and 66kV regional networks. This paper not only analyzes three-phase current protection, zero-sequence current protection, distance protection etc, but also discusses some special situations such as under voltage lockout over-current protection for transformer, remote backup protection etc.

Simulation Test System of Non-Contact D-dot Voltage Transformer

2016 ◽  
Vol 17 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Jie Yang ◽  
Jingang Wang ◽  
Ruixi Luo ◽  
Can Gao ◽  
Li Songnong ◽  
...  
Keyword(s):  
Signal Processing ◽  
Displacement Vector ◽  
Electric Displacement ◽  
Response Speed ◽  
Development Trend ◽  
Fast Response ◽  
Test System ◽  
Voltage Measurement ◽  
Simulation Test ◽  
Voltage Transformer

Abstract The development trend of future voltage transformer in smart grid is non-contact measurement, miniaturization and intellectualization. This paper proposes one simulation test system of non-contact D-dot transformer for voltage measurement. This simulation test system consists of D-dot transformer, signal processing circuit and ground PC port. D-dot transformer realizes the indirect voltage measurement by measuring the change rate of electric displacement vector, a non-contact means (He et al. 2004, Principles and experiments of voltage transformer based on self-integrating D-dot probe. Proc CSEE 2014;15:2445–51). Specific to the characteristics of D-dot transformer signals, signal processing circuits with strong resistance to interference and distortion-free amplified sensor output signal are designed. WIFI wireless network is used to transmit the voltage detection to LabVIEW-based ground collection port and LabVIEW technology is adopted for signal reception, data processing and analysis and other functions. Finally, a test platform is established to simulate the performance of the whole test system of single-phase voltage transformer. Test results indicate that this voltage transformer has sound real-time performance, high accuracy and fast response speed and the simulation test system is stable and reliable and can be a new prototype of voltage transformers.

scholarly journals (0091) Control of Open end Induction Motor by Multi-objective GA based Selective Harmonic Elimination PWM to reduce Zero Sequence Currents and Torque Ripples

2021 ◽  
Author(s):  
Jaroslaw Milewski ◽  
kalyan kumar koppolu ◽  
K Anuradha ◽  
M Surya Kalavathi ◽  
Arkadiusz Szczęśniak
Keyword(s):  
Induction Motor ◽  
Input Voltage ◽  
Good Choice ◽  
The Novel ◽  
Multi Objective ◽  
Link Utilization ◽  
Harmonic Elimination ◽  
Fundamental Quantity ◽  
Zero Sequence ◽  
Torque Ripples

A Double inverter powered induction motor with open stator winding has few benefits, including excessive error forbearance functionality, great flexibility and lesser rating of dc input voltage etc. For this Configuration, two types of Modules can implement they are Non-isolated DC link and Isolated DC link. In these two, Non-isolated DC link is a good choice due to effective DC-link utilization and ruggedness, which is very beneficial in many applications. However, this module produces more zero sequence currents (Z-SC) by means of common mode (CMMD) voltage, which flows through Dc bus. The circulation of Z-SC must as little as feasible since it merely does rise the amplitude of currents in all phases. High ripple frequency of currents and torque, In addition resulting extra loss, which not alone reduces the efficiency, but loading ability and quickens the aging of drive. The triplen harmonics can denote meticulously as harmonics with integer of three times the frequency at fundamental, when they are in Phase in all Phases forms the Z-SC. In this paper, a novel SHE method is chosen to target triplen harmonics in Single DC Source Module (Non- isolated) and holding preferred fundamental quantity, which aids in improving the torque handling ability of the motor. In addition, the investigation of dual inverter fed OEW-IM with both common DC source as well as separate DC sources also explored by SHE for different number of switching angles and variable Modulation Index (MI) towards the torque ripples and Z-SC reduction are given. The foremost challenge related with SHE method is that resolving a set of higher order nonlinear equations with number of variables. A Multi-objective GA method provided for that challenge which effects the reduction in Z-SC so that torque ripples will be minimised. Moreover, the novel SHE method reduces more number of harmonics than the conventional SHE, which further decreases TH-D with decent fundamental quantity. For validation, the essential mathematical formulations and simulation results presented.

Fast Transient Capacitor-Less Low-Dropout Regulator Based on Output Voltage Spike Reduction Circuits for SOC Applications

2019 ◽  
Vol 28 (03) ◽  
pp. 1950043 ◽  
Author(s):  
M. Jahangiri ◽  
A. Farrokhi
Keyword(s):  
Output Voltage ◽  
Input Voltage ◽  
Cmos Process ◽  
Ultra Low Power ◽  
Wide Range ◽  
Unity Gain ◽  
Fast Transient ◽  
Low Dropout Regulator ◽  
On Chip ◽  
Voltage Spike

A fast transient capacitor-less low-dropout regulator is presented in this study. The proposed LDO structure is based on Output Voltage Spike Reduction (OVSR) circuits and capacitance compensation circuits to enable a fast-transient response with ultra-low power dissipation and to make the LDO stable for a wide range of output load currents (0–50[Formula: see text]mA). The slew rate is improved with more slew current from the OVSR circuit and unity gain bandwidth is improved by a capacitor multiplayer circuit. The proposed LDO has been simulated with a standard 0.18[Formula: see text][Formula: see text]m CMOS process. The output voltage of the LDO was set to 1.2[Formula: see text]V for an input voltage of 1.4–2[Formula: see text]V. The Simulation results verify that the transient times are less than 2.8[Formula: see text][Formula: see text]s and the maximum undershoot and overshoot are 20[Formula: see text]mV while consuming only 26[Formula: see text][Formula: see text]A quiescent current. The proposed LDO is stable with an on-chip capacitor at the output node within the wide range of 1100[Formula: see text]PF.

scholarly journals Ceramic-Heterostructure-Based Magnetoelectric Voltage Transformer with an Adjustable Transformation Ratio

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3981
Author(s):  
Dmitri Saveliev ◽  
Dmitri Chashin ◽  
Leonid Fetisov ◽  
Mikhail Shamonin ◽  
Yuri Fetisov
Keyword(s):  
Magnetic Field ◽  
Lead Zirconate Titanate ◽  
Composite Ceramic ◽  
Input Voltage ◽  
Load Resistance ◽  
Lead Zirconate ◽  
Voltage Transformer ◽  
Voltage Range ◽  
Transformation Ratio ◽  
Piezoelectric Lead Zirconate Titanate

A voltage transformer employing the magnetoelectric effect in a composite ceramic heterostructure with layers of a magnetostrictive nickel–cobalt ferrite and a piezoelectric lead zirconate–titanate is described. In contrast to electromagnetic and piezoelectric transformers, a unique feature of the presented transformer is the possibility of tuning the voltage transformation ratio K using a dc magnetic field. The dependences of the transformer characteristics on the frequency and the amplitude of the input voltage, the strength of the control magnetic field and the load resistance are investigated. The transformer operates in the voltage range between 0 and 112 V, and the voltage transformation ratio K is tuned between 0 and 14.1 when the control field H changes between 0 and 6.4 kA/m. The power at the transformer output reached 63 mW, and the power conversion efficiency was 34%. The methods for calculation of the frequency response, and the field and load characteristics of the transformer are proposed. The ways to improve performance characteristics of magnetoelectric transformers and their possible application areas are discussed.

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