Circuit Happens Research Articles

Accident Alarming and Collision Avoiding System for Drowsy Drivers

Now a day’s road accident is one of the principal concerns in our states. Reckless automobile driving and driver drowsiness are the major motives in the back of those road accidents. The alarming rate of accidents and uncontrollable automobiles on the streetdemand an automatic system that could guide drivers right now in dangerous conditions. While any obstacle (just like the human, vehicle, and some other item) comes in front of the vehicle, control speed of the vehicle is the viable strategy to keep away from injuries. While a driver in a drowsy state or sleep state, give warning to the driver and control the velocity of the vehicle is the possible way to keep away from injuries. We endorse a solution in our mission to avoid avenue injuries and to manipulate the rate of automobiles. The machine will locate boundaries and motive force drowsiness using an ultrasonic Sensor and eye blink sensor and Arduino will execute a collision-avoidance gadget according to a pre-burnt code in the Arduino. The machine has also velocity manipulate features. It’s going to reduce or increase the rate of the vehicle relying on the impediment distance from the shifting car to decrease the damage or collision of an accident. Furthermore, if any obstacle from the bottom comes in the direction of cars, right now a buzzer will alert the driving force, and if any quick circuit happens in the engine element smoke sensor detecting and gives alert to the driving force and stop the automobile.

Single-pass full-penetration welding for thick stainless steel using high-current GMAW

ABSTRACT This paper describes a high-current Gas Metal Arc Welding (GMAW) process using a constant voltage power source developed for high-efficiency welding of thick stainless steel plates. A short arc length as a welding condition is preferable to concentrate the arc and obtain a deep penetration for thick plate welding. However, it is easily found that an unstable arc derived from a short circuit happens irregularly by using a general purpose GMAW with constant voltage characteristics. A ‘low-frequency modulated voltage control’ was applied for stabilizing a high-current arc that can maintain a short arc length without short circuiting. The welded joint using the developed welding process showed the similar corrosion resistance as that using the submerged arc welding; however, porosity was observed in the welded joints using the developed welding process in the current region of 400 A or above. Consequently, a new current waveform control that changes the welding current dynamically and periodically has been developed, which realized reducing porosity and single-pass full-penetration welding of 9-mm-thickness type 304 stainless steel plates with square groove.

Overload and Short-Circuit Protection Strategy for Voltage Source Inverter-Based UPS

In this paper, an overload and short-circuit protection method is proposed for voltage source inverter-based uninterruptible power supply (UPS) system. In order to achieve high reliability and availability of the UPS, short circuit and overload protection scheme are necessary. When overload or short circuit happens, using the proposed control method, the amplitude of the output current can be limited to a constant value, which can be set by the customer to avoid the destruction of the power converter, and to obtain a faster recovery performance as well. The detailed principle of the proposed protection method is discussed in this paper. It mainly contains three parts in the control diagram for current limit, first is the anti-windup in the voltage and current controllers, then the feedforward of the capacitor voltage to the current control loop, the last is the fast reset of the resonant part of the current controller when overcurrent happens. The procedure of developing the control method is also presented in the paper. Experimental results on a commercial UPS system are presented to verify the effectiveness of the control method.

Specific features of short circuit in automobile electrical system

It is shown that fires on vehicles refer to particularly severe accidents, so the problem of increasing their fire safety is extremely important. It is experimentally illustrated that in a number of cases, when a short circuit happens in an electrical circuit containing 51AH/280Aand 60AH/330A batteries, a spherical fusion is not formed in a copper conductor with a cross-section of 0.75 mm^, but there is a burnout of separate conductor wires, their adhesion to the steel surface and destruction in the immediate vicinity of the contact point. The results of a study with JSM-6390LV scanning electron microscope of copper multiwire conductors samples and steel band exposed to short circuits at a voltage of 12 and 24 V are given. There are shown photographs of the copper multiwire conductors' fused surfaces, as well as of the steel band exposed to short circuits. Characteristic diagnostic factors are found out that allow to identify the cause of the damage in the event of a fire (high-temperature exposure, short circuit, current overload) of a copper conductor in an electrical circuit with a voltage of 12 V using the method of scanning microscopy. It is found out that the detected factors are stable and are not prone to changes in the natural storage conditions of a vehicle, which was damaged as a result of thermal exposure.

Deformation and failure mechanisms of 18650 battery cells under axial compression

Abstract An important deformation mode during ground impacts of battery packs made of cylindrical battery cells is axial compression. This type of loading subjects the cell to a complex deformation pattern and failure mechanism. The design of endcaps plays an important role in such deformations. To explore the sequence of deformation and the underlying failure mechanisms, a combined experimental/numerical study was carried out. Tests were conducted on 18650 cells, and the deformation of each component was carefully investigated and documented. There are four different stages in the force-displacement curve, corresponding with deformation of various components in the endcap assembly. A short circuit happens at a displacement of 4 mm. To clarify these observations, a detailed Finite Element model was set up, covering the geometry and the mechanical property of almost all the components of the cell. Using the simulation results, the sequence of the axial compression was revealed, which was subsequently validated by Micro CT scans as well as analytical solutions. Based on the precise analysis of the mechanical behavior, the cause of the short circuit during axial loading was clarified. Two failure mechanisms in the separator at the top section of the cell explain the possible causes of short circuit.

Influence of Grid-Connected Photovoltaic Power Supply on Relay Protection of Distribution Network

随着分布式光伏发电系统的接入，配电网由单电源电网转化为多电源电网，使得原电网中继电保护中短路电流增大、电流方向改变等影响，导致短路故障时可能引起保护的误动或拒动。本文以光伏电源通过10 kV馈线接入配电网为例，利用短路电流计算公式计算短路电流大小，分析了对馈线电流保护所带来的影响，得出馈线电流保护的影响程度与光伏电源的接入位置有关。 With the access of distributed photovoltaic power generation system, distribution network sup-plied by single-ended power gradually has two port sources or multi-port sources, which result in fundamental changes to magnitude and direction of distribution network load flow, and failure to work correctly when short circuit happens. With an example of photovoltaic power supply paralleled into distribution network, this paper calculates the magnitude of short current by formula, and analyzes the effect of feeder line current protection and reclosing. The result shows that the influence to feeder line protection relates to positing of photovoltaic power supply.

Modifying the aggregated wind farm model with a controller

A large wind farm can be simplified by the aggregated wind farm models for load flow, steady and transient stability studies. When a fault (such as a short circuit) happens in a large wind farm, some of wind turbines trip while others do not. This paper is to design a controller to modify the aggregated wind farm model in the case of one or more unit removed or added from the complete model. This is without stopping the simulation process during performing the steady state and transient analysis of the whole system. This controller can modulate the status of the wind turbines in the aggregated model in a given farm according to any change in this farm. By this controller, we save effort and time to change the status of wind turbines in the aggregated model. The proposed wind farm is composed of some smaller farms of permanent magnet synchronous generators (PMSGs) and others of squirrel cage induction generators (SCIGs).

Implementation of One and a Half Breaker Arrangement in Fierza 220 KV Substation with Prozanet Scada System

Fierza Substation has a one and a half circuit breaker arrangement. In Fierza Substation scheme, two busbars are connected through three circuit breakers. The name one and a half breaker coin the fact that each circuit has the “own” breaker and the middle breaker has to be used from both circuits. In normal operation when all elements are in working condition, all circuit breakers (C1, C2 and C3) are closed and both busbars are energized and share the load through each other. Any circuit failure will trip just the two circuit breakers adjacent to the fault, in order to isolate it. No other circuit breaker will have be affected from this fault. If a busbar short circuit happens only the breakers near to the busbar will trip and all the other circuits will proceed supplying power. In this arrangement it is also possible to take out of service both busbars, and still supply the transmission line directly through the middle circuit breaker (C2) from the generator directly. The last case is only possible if both circuit’s generator and supplied transmission line are in the same diameter. The philosophy of operation of such a scheme as a case study of Fierza Substation and the problems of operating this scheme from two different Authorities (KESH and OST) at the same time, is discussed in this paper. The implementation of this case is shown with Prozanet Scada system. DOI: 10.5901/ajis.2015.v4n2s2p167

Discussion on Main Protection Configuration Schemes for Stator Internal Short Circuits in SF600-42/1308 Generator

Choosing a correct main protection configuration schemes for stator internal short circuits in generator is the premise of safe and reliable operation of the large generator. This paper firstly analyzes the general large hydro-generator stator internal short circuit fault type and fault number. It mainly does some statistics works on SF600-42/1380 generator fault location and fault number. And then through the finite element method, calculate each phase and each branch current if the generator internal short circuit happens. In the paper, we calculate the sensitivity of various kinds of main protection scheme. Get the dead zone position which easily lets the main protection device take action. Finally we summarize various factors that determine SF600-42/1380 generator main protection scheme of configuration.

An Analysis of the Impact of Rotor Winding Interturn Short Circuits on Turbine Generator Operating Variables

— In this article, the finite-element method is used to study the impact on a generator's electromagnetic torque by the position and level of a rotor winding interturn short circuit. The rules involving changes to the exciting current and the reactive power of generators are analyzed under the given adjustment patterns. The results of this study show that the saturability of ferromagnetic materials reduces the torque undulations that occur during the rotor winding interturn short circuit fault and that it improves the static stability of generators. Both the simulation experiment and the real case of a rotor winding interturn short circuit demonstrated that when a rotor winding interturn short circuit happens in a turbine generator, the generator can maintain its static stability by adjusting its state variables. This results in an increased exciting current and a decreased reactive power. The analytical method described herein allows accurate prediction of the change limits of the exciting current and the reactive power, enabling better diagnosis of the rotor winding interturn short circuit based on the two variables.

Design of a System for Avoiding Over Tripping in Coal Mine Based on CAN Communication

This paper presents a solution and design for avoiding over tripping in cases that short circuit happens underground coal mine. A method of multi-machine communication based on CAN bus is given to obtain selective short-circuit protecting. The design proposed in this paper can be easily realized and reach for demand in real application.