Switchgear Installations Research Articles

Dynamic Simulation on the Installation Process of HGIS in Transformer Substation

The technological requirements of Hypid Gas Insulated Switchgear (HGIS) installation in transformer substation is high and the control points of quality is excessive. Most of the engineers and technicians in the construction enterprises are not familiar with equipments of HGIS. In order to solve these problem, equipments of HGIS is modeled on the computer by SolidWorks software. Installation process of civil foundation and closed-type equipments is optimized dynamically with virtual assemble technology. Announcements and application work are composited into animation file. Skills of modeling and simulation is tidied classify as well. The result of the visual dynamic simulation can instruct the actual construction process of HGIS to a certain degree and can promote reasonable construction planning and management. It can also improve the method and quality of staff training for electric power construction enterprises.

A Study of Construction method of installing High-Voltage Lead-in

The construction method in electrical room with hydro power generation is well informed in drawings and according to this method, to master the actual working conditions. It's necessary to consult location of KEPCO liability threshold with the KEPCO side, therefore make a decision to install the underground cable in hydro power station in each state, including outdoor pipes and manholes. Undulating rigid polyethylene conduit (125C) and CNCV-W extra high cable are laid and installed, to make a closely analysis to the construction by reviewing its process. In this work, the key part of the KEPCO power system for House of Commons is actually based on liability threshold, even including outdoors pipeline construction, high voltage underground electrical wiring and switchgear installation. It directly reveals the contents of the proposed construction methods about Housing Corporation and the High Voltage Switchgear Installation Inlet.

News from Japan

In an attempt to reduce global warming, much research and development work has been done on electric power equipment in which SF6 gas insulation is not used. Mitsubishi Electric Corporation, Tokyo, which released 24-kV-rated dry air insulated switchgear in 2000, has completed more than 1,000 switchgear installations in the 12-, 24-, and 36-kV classes. Recently, the company developed 72-kV-rated switchgear which features low-pressurized dry air (gauge pressure < 0.2 MPa-g) insulation, improved electromagnetic actuators and condition-based maintenance (CBM) functions.

General Description and Assessment Concept for Magnetic Field Distributions Caused by Switchgear Installations

The subject of power frequency magnetic fields has become very popular in recent years. This is mainly due to two facts: the increasing usage of display units which represent a very sensitive interference victim and the increasing public concern with respect to adverse health effects caused by those fields. Switchgear installations act as one of the prominent sources of power frequency magnetic fields and, therefore, knowledge of the fields produced by them is required in order to assess any potential effects. On the other hand, switchgear installations are often very individual ones with consequently very individual magnetic-field distributions. This basically requires an individual investigation of each installation-a procedure which, in practice, has been shown as a very involved and cost consuming one. This paper describes a basic assessment method which can be used to evaluate magnetic-field distributions around switchgear installations from a general point of view, where the emphasis is on systems with a medium voltage level. The resulting field distributions can be utilized to derive and to determine appropriate distances required between switchgear and areas under consideration in order to comply with any limits concerning people or equipment

The assessment and management of older oil-filled switchgear

Older oil-filled switchgear installations require careful management if reliability problems and hazardous situations are to be avoided. Central to the effective management of switchgear populations is an understanding of the deterioration mechanisms and the actions that can be taken to minimise failures. In addition, the adoption of an assessment methodology, including appropriate diagnostics, provides sound information on which to base decisions on switchboard replacement.

Measurements of fast rise-time transients switching large 13.2 kV motors

A method of fast rise-time transient voltage measurements on actual 13.8 kV switchgear installations is presented. The system configurations as well as the instrumentation and test set-up are described. Results are presented from both low voltage (50 V) and rated voltage (13.8 kV) tests. Measurements on air magnetic and vacuum circuit breakers are included. >

Contribution on the Specification of an Aging Test for the Insulation of Enclosed, Air-Insulated Switchgear

Because of high humidity and condensation, layers of moisture are formed on the surface of insulating materials in indoor switchgear installations which, as a result of contamination, are conductive electrolytic boundary layers. When this happens, electrochemical interactions can produce aging of the insulating material surfaces that may even lead to failure of the insulation. Basic investigations were carried out on a rod-shaped model insulator with simul taneous subjection to an electric field, moisture, and polution. Electrical, chemical, and optical diagnostic methods make it possible to determine aging related surface changes. Based on these results and taking into account the results of work done by the International Working Group IEC-SC17/WGIO Aging Tests, proposals are discussed for an aging test for enclosed indoor switchgear. In particular, procedures are discussed for simulating the aging phenomena with time compression. The suitability or nonsuitability of individual parameters are discussed.

Control and Auxiliary Power Systems for Industrial and Commercial Switchgear Installations

Protective relays for power systems are ineffective if no energy is available to actuate the circuit interrupter when a fault occurs. Therefore, control power systems deserve careful design attention. The design of both ac and dc control power systems is reviewed, and some design criteria for these systems are listed.

The Crossed-Ring Arrangement A New Concept for H.V. Switchgear Installations

A new concept for high-voltage switching stations is proposed, which offers advantages compared to the commonly used breaker-and-a-half scheme as regards availability and costs.

The Calculation of Overpressure in Metal-Enclosed Switchgear Due to Internal Arcing

The mechanical stress of metal-enclosed switchgear installations due to fault arcs can be predicted by means of pressure calculation. In this paper a number of calculation methods is discussed. The results of pressure calculation are compared with pressure measurements performed in model switchgear cubicles. It is shown, that simplifying assumptions in some calculation methods lead to inaccurate results. Pressure calculation for switchgear cubicles with effective pressure relief openings should take into account the spatial limitation of arc energy input.

Novel capacitor-divider voltage sensors for high-voltage transmission systems

For some time, it has been recognised that conventional capacitor voltage transformers (c.v.t.s) have transient response limitations which affect the performance of modern high-speed protection. To take advantage of existing and new types of distance protective systems, capable of performing accurately withing the first 20 ms of fault inception, a high-fidelity voltage measurement system which overcomes the limitation of conventional c.v.t.s has been developed. The novel high-fidelity voltage sensor comprises a conventional capacitor divider and solid-state amplifier system, the latter being suitable for application with existing designs of capacitor voltage transformer, purpose-designed capacitor voltage dividers, or with capacitor-probe facilities in SF6 metal-clad switchgear installations. A summary of the results of the various tests which have led to the development and design of a fully engineered system are described. Reasonable correlation is shown to exist between actual performance of the novel c.d.v.s on the 400 kV system and laboratory tests. Technical performance requirements for high-speed protection covered by the IEC Recommendations, Publications 186, 1969, and 186 A, 1970, and other special requirements are evaluated in a manner which could be used as a basis for design specifications. The paper concludes by considering economic aspects and future possibilities.

High Voltage Single Column Isolators

The increase in number and size of outdoor switchgear installations up to the highest service voltages has led to the development of a new single column isolator of the pantograph design. This paper describes the design and operation as well as the tests to which this isolator was subjected.