Explosive Switch Research Articles

Research on Health Diagnosis Technology of Key Equipment in Coal Mine Power Grid

Aiming at the problem that the traditional fault monitoring method of mine power supply equipment is single and can not effectively reflect the real-time working state of equipment and cables, this project studies a comprehensive intelligent fault diagnosis and monitoring early warning technology method. Through the research of two key technologies, power quality analysis technology based on harmonic method and insulation condition monitoring technology of electrical equipment, an intelligent diagnosis system for the health condition of mine power supply equipment is designed and formed. Through real-time monitoring of power grid harmonic parameters, power grid operation parameters, insulation parameters, and temperature parameters, the system can comprehensively analyze and judge the working status of various equipment and connecting cables in the underground power grid to comprehensively judge the faults of high explosive switches, transformers, and connecting cables, and achieve the purpose of fault location and early warning.

Fuse Selection for the Two-Stage Explosive Type Switches

In the two-level explosive switch destruction of a delay happens in the form of electric explosion. Criteria of similarity of electric explosion in transformer oil are defined. The challenge of protecting the power electrical equipment from short circuit currents is still urgent, especially with the growth of unit capacity. Is required to reduce the tripping time as much as possible, and limit the amplitude of the fault current, that is very important for saving of working capacity of life-support systems. This is particularly important when operating in remote stand-alone power supply systems with a high share of renewable energy, working through the inverter transducers, as well as inverter-type diesel generators. The explosive breakers copes well with these requirements. High-speed flow of transformer oil and high pressure provides formation rate of a contact gap of 20 - 100 m/s. In these conditions there is as a rapid increase in voltage on the discontinuity, and recovery of electric strength (Ures) after current interruption.

Transformer Oil Dielectric Strength in the Contact Gap of the Explosive Arc-Extinguishing Device

The article describes the experimental results on the breakdown of the high-speed flow of transformer oil. In real conditions, the flow moves in the contact gap of a high-voltage explosive switch with speeds from 67 to 152 m / s. The geometry of the contact gap is sharply inhomogeneous and forms turbulence in the flow zone. In the arc chute medium the air inclusions pass from the dissolved state to the gaseous and the emerging bubbles enter to the electric field. Breakdown occurs, mainly through gas inclusions. In the moment, the gradient of the breakdown voltage is reduced by 91.6% compared to the static state of the oil. The experiments were carried out on the model of a high-voltage explosive switch, connected to the power circuit of the surge generator. The probing of the gap was made by a standard pulse of 1.5 / 50 μs. As a result, the dependences of the gradient of the breakdown voltage on the flow rate of the transformer oil for the usual geometry of the high-voltage explosive switch contact system are constructed.

Using of explosive technologies for development of a compact current-limiting device for operation on 110 kV class systems

This paper considers the possibility of creating on new physical principles a highspeed current-limiting device (CLD) for the networks with voltage of 110 kV, namely, on the basis of the explosive switching elements. The device is designed to limit the steady short-circuit current to acceptable values for the time does not exceed 3 ms at electric power facilities. The paper presents an analysis of the electrical circuit of CLD. The main features of the scheme are: a new high-speed switching element with high regenerating voltage; fusible switching element that enables to limit the overvoltage after sudden breakage of network of the explosive switch; non-inductive resistor with a high heat capacity and a special reactor with operating time less than 1 s. We analyzed the work of the CLD with help of special software PSPICE, which is based on the equivalent circuit of single-phase short circuit to ground in 110 kV network. Analysis of the equivalent circuit operation CLD shows its efficiency and determines the CLD as a perspective direction of the current-limiting devices of new generation.

Design of a dissipation circuit for a 560 MJ inductive storage supply

The authors report on the design and component testing of a dissipation circuit for a 560 MJ inductive storage supply. This storage supply is charged by a 5 MA battery power supply. This battery upgraded supply (BUS) requires energy management at either the end of a test or as a means of aborting a test in the event of a fault. Energy management is accomplished by diverting the supply current into large dump resistors capable of dissipating the inductively stored energy through resistive heating. After most of the energy has been resistively dissipated, a low residual current exists in the resistor circuit due to the applied battery voltage of the battery power supply. This current is interrupted with final interrupter switches in series with the dump resistors. Both the divert and final interrupt switches are explosive opening switches. Special design features of these components include low-cost extruded aluminium switch elements for use in both the divert and final interrupt positions that have the designed-in capability to open thermally in the event of an explosive switch failure.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Dynamic behavior of an explosive opening switch

An investigation into the dynamic behavior of explosive opening switches, which are used in power compression circuits for railgun research, is summarized. During switch operation, a primacord is ignited at one end of the switch, and a detonation wave propagates down the primacord along the length of the switch. It is assumed that all locations along the length of the primacord detonate simultaneously, a line detonation. A 2-D Eulerian hydrocode was executed to simulate the early-time dynamics of the explosive switch. Three different opening switch element geometries were considered: a circular external shape with a round internal hole, a faceted (or hexagonal) external shape with a round internal hole, and a circular external shape with a round internal hole that has four internal notches directed along predetermined shear planes. The results provide insight into the pressures, stresses, and strains experienced at various locations in the switch.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Study of high current commutation by explosive switch

The basic experimental data obtained with a large current opening switch for current commutation using explosives are presented. The experimental results show that currents up to a maximum of 40 kA can be completely interrupted within 30 mu s. The mechanism of current interruption using a thin conductor plate and methods of measuring interrupting current with a pick up coil and taking photographs with a high-speed camera (1 frame/ mu s) are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Explosive opening switch work at Westinghouse

An explosive switch that commutated 315 kA into a resistor and a second version designed to switch up to 1 MA into an HPG (homopolar generator) -driven railgun system are presented. These switches are located very near the load and consist of a set of main busbars in a low-inductance configuration shorted by a thinner switch busbar. Linear-shaped charges are used to sever this switch busbar at several locations when a preselected current level is attained, commutating the current into the load. The feasibility of multishot explosive switches for electromagnetic-launch systems is also considered.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Summary of experimental results using the REMGUN III HPG facility

As part of the ongoing research program into electromagnetic (EM) guns at the Royal Armament Research and Development Establishment (RARDE), work has been carried out on several railgun barrel/switch systems which have been installed in an enclosed 100-yd range. Using the REMGUN III 6.7-MJ HPG (homopolar generator) pulsed power supply, explosive and mechanical commutating opening switches have been built and tested. This includes the IRD railswitch, the LYNEX linear explosive switch (marks 1 and 2), and the Royal Ordnance gas-operated switch. The first three were fired with a 25-mm-square bore gun using solid armatures, while the fourth was incorporated into a combined conventional/EM round-bore plasma-driven gun. A description of these switches is presented together with a summary of results and diagnostics used.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Explosively Driven High-Energy Generators

Design information, circuit analysis, and comparison of calculated and experimental results are presented for three different explosively driven current generators. These generators are all of the helical coil construction. The largest of these generators (9-in. diam) used 17 lb of high explosive to produce an output energy of 1.5 MJ. An exploding wire switching technique has been developed for use with these generators to produce output currents suitable for high-energy pulsed plasma experiments. The combination of explosive generator and switch has produced peak currents of 5 MA in 3 μsec and peak dI/dt values in excess of 4.0×1012 A/sec.

Design and performance of a compact surge generator

A compact surge generator for investigation of a fast, linear, pinched discharge using only moderate energy storage is described. The technique of construction using an explosive switch to obtain low inductance, and the method of measuring current are discussed. The behaviour of the surge generator when short circuited is determined from the current waveform, and inductance and resistance values are deduced. The inductance and resistance of the switch are much less than those for the whole circuit, with a linear discharge in deuterium.