Voltage Protection Research Articles

Retrofit of a Governor Electronic-Analogic of a Francis Turbine of 180 MW of Decade of 1960 Using Microcontroller Arduino Due

This paper describes the retrofit of a governor electronic-analogical of a Francis turbine of a synchronous generator of the decade of 1960. The author has many years of experience in maintenance in governors of hydroelectric power plants including excitation systems. Governors are responsible to maintain constant the frequency of a power electric net. The original model of the governor in question was obtained in local field tests, not related in this paper. In this retrofit, time constants were maintained to respect the original project and avoid hydraulic harmful and dangerous transitory problems. The original continuous model of the governor was simplified toa a second order model. The second order continuous model was emulated to a discrete system. The difference equation was created and microcontroller Arduino Due was programming. The digital controller produced, was syntonized to cancel the mathematical function of the servomotor, to reduce the grade of the resulted system obtaining a second order system. The hydraulic part of the governor was simulated using 741 operational amplifiers. During the tests in the workbench the author burned two Arduino’s electronic cards so it was necessary to create the electronic interface between Arduino and the 741 amp op including over and under voltage protection. The complete set was successfully tested in workbench. The mathematical models were priory simulated with Matlab-Simulink and there were the corresponding electronic simulations in workbench that confirmed the results. This retrofit solution, using Arduino Due, is of low cost compared to traditional manufacturers.

COORDINATION OF LOW VOLTAGE PROTECTION

COORDINATION OF LOW VOLTAGE PROTECTION   Sona Rzayeva Head of laboratory Department of Electromechanics, Azerbaijan State University of Oil and Industry, Azerbaijan, Baku Seymour Beylarzadeh Master of the Department of Electrom

Efficient protection and control of electric drives using solid state circuits

The paper presents the results of a theoretical study of semiconductor circuits carried out for practical use in the development of a non-contact switching and control apparatus for starting control and under voltage protection of AC motors. According to the results of the analysis of semiconductor circuits, it is recommended to use them when creating relay devices for the automation of electrical equipment. Theoretical investigated semiconductor circuits were used in the creation of a non-contact starter of an asynchronous electric drive with protection against operation at minimal voltage drops in the network.

Voltage Feed-Forward Controlled 75W Forward Converter with Type-2 Compensation and Protection Circuits

Abstract: In recent years, DC-DC converters find many applications in low to medium power range. The isolated converters are used in medium power application such as military, electric vehicle (EV) and space industries since they provide isolation between input and output and protection from input side faults. These are made capable of providing a specified output voltage by managing the PWM pulses delivered to the switching device's gate. This paper presents use of voltage feed-forward method which helps in suppressing effect of input line harmonics and disturbances and gives regulated output voltage. The converter is operating at a switching frequency of 140 kHz and behaviour of switching device is not taken into consideration. The converter has protection circuits like over voltage protection (OVP), over current protection (OCP) on input and outputs, under voltage protection (UVP) which protects from abnormal operating condition. The design and simulation results of the feed-forward technique with type-2 compensation and protection circuits are discussed.

Battery Protection System Against Undervoltage and Overvoltage i n Off Grid Systems Photovoltaic

Electrical energy at this time is widely used by most humans, of course also disturbances in the distribution of electricity cause inhibition of daily human activities. Disturbances that occur can be classified into various kinds, one example is Undervoltage and overvoltage. Of course, these disturbances can arise when the use of electrical loads that are sensitive to damage. To secure electrical loads that are sensitive to damage, a control system is made overvoltage and undervoltage using a microcontroller Arduino Mega and the actuator is a relay. This research tries to solve the problem of over voltage, under voltage, and unbalanced voltage with a visual basic-based voltage protection system. This system research uses visual basic as an interface and as a data logger to facilitate operators in analyzing disturbances, and with the help of the Arduino Mega2560 microcontroller which can be used to process and send data to the visual base. Thus, this research is expected to help users to e easily monitor and analyze disturbances.

Design of Household Electricity Protection and Monitoring Automation With IoT ESP32

existence of a household electrical protection and monitoring system to minimize danger. Therefore, a prototype design tool for household electricity protection and monitoring automation with IoT ESP 32 is developed. With the aim of carrying out voltage protection and electricity monitoring with a normal voltage of 220 VAC. designed to increase the existing protection system in the household, not to replace the function of the MCB. With a success rate of 99.6% voltage measurement, 97.5% current and 97.8% power measurement. Testing the tool using an inductive load in the form of a 45 watt 35, watt, 26 watt LED lamp and a resistive load in the form of a 400 watt iron set at the maximum hot point. below 210 VAC.

Reverse voltage protection circuits for power MOSFETs in low dropout power applications

This paper proposed three reverse voltage protection circuits for the power MOSFETs in low dropout power applications. Power devices are vulnerable to instantaneous current overshoot when the input voltage is lower than the output voltage. Compared with conventional solutions using diode for reverse current block, the proposed three structures consume fewer voltage drop during normal operation. The first design is suitable for applications with wide output ranges but requires the largest die area. The other two solutions are for applications with low output voltages, and are characterized with effective area arrangement and dead-zone free control, respectively. The proposed three protection structures require 126.2%, 12.25% and 43.05% extra die area of the power devices, respectively.

Comprehensive Control of Reflux Safety Parameters Based on Flexible Grounding Scheme in DC Railway Electrification System

Currently, the excessive rail potential (RP) and stray current (SC) are disasters to the safety of equipment and staff in dc railway electrification system (dc RES). However, abnormal increase of RP and SC still exists and the coupling relationship between RP and SC with the complex grounding scheme has not been clarified. In this article, a flexible grounding scheme (FGS) is proposed to realize the comprehensive control of RP and SC with dynamic operation of multitrain. By establishing the simulation model of dc RES with FGS, the coupling mechanism of the abnormal increase between RP and SC is clarified. In order to prove the effectiveness of FGS, simulation results of dc RES with ungrounded scheme, over voltage protection device (OVPD) grounded scheme and FGS are compared. Field tests of reflux safety parameter (RSP) are carried out in Hefei Metro Line 2 with different grounding resistance. Simulations and field tests show that coupling effect between RP and SC at multiple stations is obvious, and FGS can realize the comprehensive control of RP and SC effectively.

Over Voltage and Under Voltage Protection System Using IoT

Sudden fluctuation in voltage may cause a serious problem in industries and home appliances. These fluctuations may significantly impact the power quality as well as the reliability of other voltage controlling devices. However, this paper discussed about designing for under voltage and over voltage protection to protect and extend the lifespan of home, office and industrial equipments. The AC voltage sensor module ZMPT101B is used in detecting a voltage of -6% of the rated voltage and it is recognized as under voltage while 10% of the rated voltage is recognized as upper voltage. The rated voltage of single phase is normally supply 230 V. Moreover, the sensor is attached with ESP 8266 WiFi platform so that the user can observe the voltage condition through Blynk application. As a conclusion, the combination of voltage protection system through Internet of Thing (IoT) device may contribute to the user.

Quantifying the uncertainty imposed by inaccurate modeling of active distribution grids

Replacing conventional generation with inverter-interfaced units has turned distribution networks (DNs) from consumers to active and responding intelligent DNs. These modern DNs contain several devices that can support the transmission network (TN) and system stability. Typically, deterministic and aggregated models for inverter-interfaced generation and conventional loads are used to include entire DNs in bulk system stability studies, and contributions from smart loads are neglected. This approach introduces errors to the dynamic modeling that can lead to instabilities. In this paper, we first present a full detailed model of a modern DN, enhancing existing thermal load and distributed generation models to include frequency and voltage support and protection functions required in low-inertia systems. Then, we incorporate the uncertainty that stems from the parameterization of such units using a Monte-Carlo method. Finally, we assess the impact of neglecting specific protection and support functions against frequency disturbances. The results show the crucial importance of accurately modeling protection and support functions to analyze the impact of modern DNs on bulk system stability. In addition, the findings highlight the increased relevance of considering uncertainty in stability studies of weak and low-inertia power systems.

A novel voltage protection method for multi-cell lithium-ion battery protection IC

Lithium batteries have been widely used in portable electronic devices and other electric products. To ensure safety and long life, a lithium battery needs to be equipped with a protection chip. A novel voltage protection method for three-cell lithium-ion battery protection IC (Integrated Circuit) is proposed in this paper. A new voltage protection circuit structure and a three-cell lithium battery voltage sampling circuit are presented to improve the circuit performance of the chip and reduce the dynamic power consumption and chip area of the system. With a new time-division multiplexing circuit structure, the area and power consumption of the chip are greatly reduced. Moreover, this solution can be extended to any number of lithium battery packs connected in series for voltage protection. Testing results show that the overcharge detection accuracy can achieve better than ±15mV, the over-discharge detection accuracy can achieve ±7.5mV, the power consumption of the voltage protection module is 1.7μA, and the area is 300μm×500μm2.

An ENS-Oriented Voltage Protection Scheme for Inverter-Based Generators in Active Distribution Networks

This paper unveils that maintaining a proper voltage protection for inverter-based distributed generations (IBDGs) using overcurrent relays and during the power grids’ faults with considerable resistance stands as a complicated issue. To overcome this challenge, this paper presents a new protection scheme through developing a voltage index ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VI</i> ) and launching a new characteristic that concentrates on minimizing energy-not-supplied ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ENS</i> ). If the developed voltage index is in place, the near area faults with considerable resistance could be effectively discriminated from those at a far distance. Moreover, the adopted characteristic represents two operation modes known by fast and slow modes. For the faults in the vicinity of the IBDG, independent from resistances, the fast part of the proposed characteristic and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VI</i> are jointly corresponded to clear the faults swiftly. Moreover, to satisfy coordination time interval (CTI) among relays pairs, the slow part acts in the conventional manner which is corresponded during the backup process. To evaluate the performance of the proposed method, numerical studies are carried out on IEEE 33-bus test system. Results show that the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ENS</i> index is enhanced while meeting IBDGs’ voltage protection requirements and satisfying selectivity tasks.

A numerical analysis model for inception and propagation of positive upward leader from UHV DC transmission lines

As the upward leader from the transmission line plays a vital role in the interception of lightning downward leader, the proper description of upward leader characteristics is beneficial for improving the evaluation accuracy of lightning performance for UHV DC transmission lines. Based on the leader discharge theory, a novel numerical analysis model to simulate the inception and propagation process of positive upward leader from the transmission line was proposed. The model-based calculation results show good agreement with the data of laboratory long spark discharge, natural lightning observations and operation experience of transmission lines, which verifies the validity of this model. Moreover, the influence of operating voltage, protection angle and tower height on the upward leader characteristics for the typical UHV DC transmission line was analyzed. The results show that the lightning interception ability of upward leader from the positive polar conductor is enhanced with the increase of voltage level, protection angle, and tower height, which theoretically illustrates that installing the positive polar conductor closer to hillsides, adopting the negative protection angle and reducing the tower height are effective lightning protection measures for UHV DC transmission lines.

An analytical review for the power system of a spacecraft

Electrical bus is needed for the operation of all active spacecraft systems and subsystems. In the spacecraft mechanism, the battery charging system and the bus storage continued with bus control, the conditioning and bus distribution is an essential part for keeping the spacecraft in working mode. In this paper, the discussion for electrical power system (EPS) analysis in the spacecraft body will be elaborated from the previous research papers on this subject covering the topics of solar array, solar array drive, over current and over voltage protection, battery charging and discharging, bus control, conversion.

Design of Protection Strategies and Performance Analysis of an HVDC Link During Multiple Disturbances

In High Voltage Direct Current (HVDC) transmission system applications, the control and protection system plays an essential role in the overall performance. This paper aims to give solutions to some performance problems that can occur in the HVDC link. In this paper, ways to mitigate this serious malfunction of the commutation failure process in the operation of HVDC converters are studied and protection functions like the Commutation Failure Prevention (CFPREV) have been used. Furthermore, HVDC transmission systems are vulnerable to DC faults and its protection becomes ever more important with the fast growth in the number of installations. In this context, the DC fault protection function is one of the most important challenges to the development of HVDC transmission systems. The dynamics of the studied power system including the HVDC link are thoroughly investigated in this paper through various simulation scenarios.

High Voltage Direct Current (HVDC) Transmission and Protection System

High Voltage Direct Current (HVDC) Transmission and Protection System

Amorphous Carbon Coatings on Glass for High Voltage Protection

Radio frequency Hollow Cathode based hybrid process integrating both Physical Vapor Deposition and Plasma Enhanced Chemical Vapor Deposition was used for deposition of amorphous carbon on glass samples. The films were subjected to high voltage pulses and the performance was compared with uncoated glass samples to test the protection ability of the films, the ability to prevent the deteriorating effects of corona flashovers/arcs. In contrast to the uncoated glass the well adherent carbon films with thicknesses between 3.5 and 17 μm exhibited an excellent protection of the glass substrate against the flashovers/arc damages in both polarities of the electric field with voltages up to 300 kV.

Design of Smart Energy Meter with IOT Using Arduino Mega

Electricity is one of the essential needs of human. It's commonly used for domestic, industrial, and agricultural purposes in day-to-day life. Most folks know the role of the energy meter within the electricity grid. It’s a fundamental component of the distribution grid. The energy meter helps the utility (electricity distribution company) to account for the utilization of electricity by the buyer on a KW per hour basis. To know this we want to seek out the drawbacks of the present energy meter, and therefore the biggest problem in electricity metering. The most important problem in electricity distribution is collecting meter reading data. Straight away meter reading is collected manually, which provides scope for corruption and human error in reading. It is the wastage of manpower and utility of resources. Our existing electricity meter isn't tamper-proof. There is to several temper cases are detected. In the existing meter, there is no under voltage and over voltage protection, as well as there is no over power use alert system. Because of these problems, the utility is unable to gather a fine for max demand cross. Power theft is the biggest problem in recent days, which causes a lot of loss to electricity boards. To overcome these drawbacks, the IoT-based Smart Energy Meter (SEM) is developed.

A network-based structure-preserving dynamical model for the study of cascading failures in power grids

In this work we show that simple classic models of power grids, albeit frequently utilized in many applications, may not be reliable for investigating cascading failures problems. For this purpose, we develop a novel model, based on a structure-preserving approach, to obtain a network-based description of a power grid, where nodes correspond to generators and buses, while the links correspond to the physical lines connecting them. In addition, we also consider classic voltage and frequency protection mechanisms for lines and buses. Considering the Italian power grid as a case study of interest, we then investigate the propagation of an initial failure of any line of the power system, and compare the predicted impact of the failure according to different assumptions in the model such as the presence or absence of protection mechanisms and a simplified description of the system dynamics. In particular, it can be observed that more realistic models are crucial to determine the size of the cascading failure, as well as the sequence of links that may be involved in the cascade.

Research on the influence of distributed generation and its grid connection on power system

Abstract China’s per capita resources are scarce and consumed very quickly. New energy power generation has the characteristics of green, environmental protection and renewable, and it is the main development direction of the current and future power industry. With the continuous expansion of new energy power generation and grid-connected scale, various adverse effects brought to the power grid in the process of grid-connected are gradually emerging and becoming more and more serious.This paper briefly introduces the distributed power generation, and then studies and analyzes various problems brought by the grid connection of new energy to the power system from the four aspects of grid voltage, grid harmonics, grid frequency, and grid protection, and gives some solutions. For example, if the power generation equipment meets the grid-connection standard, a real-time monitoring device for power quality and a dynamic reactive power compensation device can be installed; for harmonic pollution problems, multi-pulse converters and power filter devices can be used; for power quality problems in the distribution network, the structure of the power grid can be optimized., Reasonable selection of the impedance ratio of the circuit, etc.