GGas Insulated Switchgear - Ganz Transelektro Electric Co.

GAS INSULATED SWITCHGEAR

Electric Co. Ltd.

CONTENTS

Introduction................................................ 2

Main features............................................... 3

Circuit breaker..............................................4

Disconnectors,maintenance and highspeed earthing switches.......................... 7

Current transformer.................................... 9

Voltage transformer....................................10

Joining and expansion units.......................11

Surge arrester.............................................12

Terminations...............................................13

Gas monitoring systemand local control cabinet...........................14

Design and productionfacilities......................................................15

Development facilities............................... 16

Quality assurance...................................... 17

Quality control...........................................18

Ganz Transelektro Electric Co. Ltd. 1

INTRODUCTION

The increased demand for electrical energy in big cities and industrial areas has made it necessary to bring high voltage systems directly to the load centres. It is very difficult, and sometimes impossible to find a suitable place for installation of the air insulated switchgear (conventional type).

At the same time in many areas (cities, industrial centres, seaside etc.) the air has become very polluted for using any sort of the open type insulation.

The SF gas insulated switchgear (GIS) guarantees outstanding advantages for the planning and operation of high voltage supply networks. For instance, the space requirement can be less than 10% of the space taken up by an equivalent conventional installation.

As all live parts are metal enclosed and hermetically sealed, the SF GIS is completely immune to the atmospheric pollution (fog, sand, salt...)and industrial pollution (dust, smoke, gas...). With SF GIS all foreign bodies (persons, animals, tools) are prevented from coming into contact with live parts. This ensures maximum safety to personnel and increased continuity of operation.

Harmful effects, caused by corona and radiointerferences, are totally eliminated and thanks to the low noise level of the driving mechanisms the SF GIS is very suitable for installation in residental areas.

All switchgear enclosures and conductors aremade of aluminium. The results of this design are low enclosure losses and light weight.

The switchgear is shipped as large sub-assemblies and as complete factory tested package feeders.The cost of the site erection and commissioning is minimized.

The well known modular design allows the switchgear to be adopted to the specific requirements of each particular case (one line diagram, layout, section...).

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Ganz Transelektro Electric Co. Ltd.2

MAIN FEATURES

Single phase enclosed designSmall dimensions allowing economical spacesavingIndoor and outdoor applicationsHigh reliability in service, independence of ambient influencesFlexibil ity and optimal arrangement of equipment, assured by highly modular element systemLight weight, gastight aluminium enclosures with low electrical losses and corrosion resistanceEarthed enclosures assuring maximal protection against electrical shock for the operating personnelLow maintenance and long service lifeEnvironmental friendly behaviourEpoxy-resin barrier and support insulatorsCircuit breaker on single pressure principle, actuated by hydraulic driveProtection against dangerous overpressurethrough bursting membranes Quick site assembly assured by in-factorypreassembled bays and shipping unitsCompliance with relevant international standards(IEC 517; IEC 694...)

72,5 kV GIS, Qatar, "Al Bidda"


Assembly of a circuit breaker pole

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CIRCUIT BREAKER

The circuit breaker is single pressure double flow type, which by synchronizing puffer, suction, self blast and nozzle ablation effects, significantly boosts the circuit current breaking performance.

The operating mechanism can allow three-pole operation or single-pole operation according to the Clients' request.

The circuit breaker is operated by a reliable hydraulic mechanism installed directly on the circuit breaker supporting structure. The hydraulic mechanism operates in the range of +50°C and -25°C ambient temperature. The production is based on 40 years of experience and continuous development.

One closing coil and two trip coils are normally provided for operationcontrol.

The circuit breaker can be operated remotely or locally from the local control cabinet.

The interrupt ing chamber i s equipped with facility for filtering the humidity and absorbing the gas decomposition products.

All inspection and maintenance operations can be easily executed without having to dismantle the adjacent parts.


Sequence of current interruption

SCHEME OF THE EXTINGUISHING CHAMBER

Closed position

Arc quenching

Arc quenching

Arc quenching

Open position


high pressure without pressure

SCHEME OF HYDRAULIC OPERATING MECHANISM

Position: OFF

Position: ON

8Ganz Transelektro Electric Co. Ltd.6

The modular system consists of five different switching elements:

busbar disconnectorsline disconnectorsangle disconnectorsmaintenance earthing switcheshigh speed earthing switches

The disconnectors, maintenance earthing switches and high speed earthing switches are equipped with standard main parts:

The motor driven operating mechanism is based on a rotating spindle with movement in both directions for 9 0 ° .The mechanism contains locking system, position indicator, auxiliary contacts and plug base for the cable connection. The mechanism can be driven by motor or by hand.

The crank housing with sealing and leading systems.

The three poles of each apparatus aremechanically coupled in any position and operated in common by the motor mechanism.

The disconnector (angle or line type) can be installed alone or together with an earthing switch in common enclosure.

Each type of the earthing switches could be installed alone or together with the disconnector in common enclosure.

The high speed earthing switch is similar to the maintenance earthing switch, but it is provided with a spring stored energy type operating mechanism.

DISCONNECTORS, MAINTENANCE AND HIGH SPEED EARTHING SWITCHES


Section of maintenance orhigh speed earthing switch

Section of angle disconnector with maintenance or high speed earthing switch

Section of busbar disconnector Section of angle disconnector


CURRENT TRANSFORMER

The current transformer has toroidal cores installed concentrically to the primary winding formed by the inner conductor.

The transformer cores are tensioned in a retaining frame and are inserted in gas space of the housing together with an internal screen.

The ends of secondary windings are brought into the terminal box through gastight bushings.

Cores with secondary windings are designed in accordance with the requirements for accuracy class and power rating.

Changing of transformer ratio is carried out in the terminal box.


VOLTAGE TRANSFORMER

The voltage transformer is inductive type.

The main insulation is SF gas, while synthetic foils are used as insulation between the windings.

It can be arranged in front of or behind the outgoing feeder disconnector or on the busbar.

The primary conductor, supported by a gastight bushing, forms the connection to the switchgear.

The secondary connections are accessible via terminal box.

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JOINING AND EXPANSION UNITS

Joining units are used for interconnecting the various apparatuses and bus sections of the GIS.

These units generally contain connection elements: T-housing, X-housing and straight (SF tube) element.

The active parts are current conducting tubes, tulip and/or MC contacts.

The thermal expansion of the long enclosure, as well as the mounting and manufacturing tolerances are compensated by metal bellow compensators.

300 kV line connections with GIS busducts, Malaysia "Paroi".

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SURGE ARRESTER

Gas insulated surge arresters can be supplied where the use of outdoor surge arresters is not practicable (cable bays or connections to transformers through busduct) or where the overhead line termination is too far from the GIS to ensure a coordinated protection.

The surge arrester is made from first class ZnO discs protected by gastight insulating cylinder and inserted in the metal enclosure.

Screens are used for the correct distribution of the electrical field.


TERMINATIONS

CABLE END

The cable end facilitates the interconnection of the HV cable and the GIS. The cable end contains a cast resin cable end insulator - always supplied by the cable manufacturer - enclosure and contact system. The main insulation of the cable end is SF gas and this gas compartment is usually independent of the other gas compartments in the switchgear bay.

SF - AIR BUSHING

The overhead line is connected to the GIS through the SF -a i r bushing. Its external cover is a conventional gastight porcelain insulator with suitable screen formation and with potential control ins ide . The bush ing

current conducting tube is located in the axis of the porcelain insulator. The bushings can be installed in different arrangements according to the connection possibilities of the over-head lines.

SF - OIL BUSHING

This bushing ensures direct connection between the trans-former and the GIS. The insulating body of the bushing is made of epoxy-resin always supplied by the transformer manufacturer. The GIS manufacturer suppl ies the enclosure of SF gas insulated transformer connection including the contact system and the anti-vibration compensator to damp the vibration of the transformer.

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Gas schematic diagram and local control cabinet. of a line bay

Local control cabinets at 132 kV GIS, Kuwait "Funaitees F".

The switchgear bay is divided into several gas compartments and each gas compartment is monitored by a temperature compensated gas density relay. Beside this relay each gas compartment is equipped with a bursting membrane, manometer (if requested), filter and gas connection valves.

The local operation of GIS is performed from the Local Control Cabinet. Each switchgear bay has its own cabinet equipped with all devices necessary for the operation. Each cabinet generally includes alarm annunciator, mimic diagram, position indicators, control and selector switches and other necessary instruments. The cabinet also contains terminal blocks and all necessary auxiliary relays for the electrical interlocking system.

GAS MONITORING SYSTEM ANDLOCAL CONTROL CABINET


Design, planning and layout of gas insulated switchgear substation is carried out by experts using modern computer aided design tools.

Model-based computer graphics are used for creating substation models.

Our semi-automatic production process makes use of a computer aided manufacturing requirements planning (MRP) which assures economic procurement of materials and timely manufacturing progress.

Quality control inspections begin at the conceptual stage andtrack the whole design and manufacture process.

Ganz Transelektro utilizes a new up-to-date switchgear plant(8000 m ) conceived and realized in order to grant the highest standard of efficiency and quality in production process.

The new plant at Tápiószele, Hungary with the new GIS factory in the front of the picture.

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DESIGN AND PRODUCTION FACILITIES


Gas velocity map inside the nozzle of the extinguishing chamber

Computer aided design: Electrical field distribution at the open contacts of a disconnector tested with max. BIL test voltage

DEVELOPMENT FACILITIES

All of the most advanced calculations and simulation techniques are used during the development stage of the various components and in particular:

two-dimension and three-dimension finite element softwares for evaluation of the dielectric strengthfinite element software for stress analysis of GIS enclosurestwo-dimension and three-dimension software for gas flow analysis forevaluation of the performances of the interrupting chambers during various network operating and fault conditionsmodelling of hydraulic drives

All the calculations and simulations are fully integrated by experimental data obtained during type and research tests.


View of a section of the assembly hall at the new GIS factory

QUALITY ASSURANCE

The applied Quality Assurance System for design, development, manufacturing and testing is in compliance with the standard of:ISO 9001 (UNI--EN 29001)


QUALITY CONTROL

All quality control operations are carried out on all materials, subcomponents and components up to the final tests on the shipping units.

Apart from the tests carried out at Ganz Transelektro test rooms,which are under periodical control of independent institutes, all materials and subcomponents are subject of the required tests at the subsupplier's workshop.

In order to allow the End User to control and to participate in the test program, a Quality Control Plan is prepared during the contract stage.

The 750 kV GIS high voltage test transformer and the coupling capacitor


FLOW CHART OF QUALITY CONTROL PROCESS REGARDING THE EPOXYINSULATOR DISCS MANUFACTURED BY GANZ TRANSELEKTRO

Supporting insulator with tulip contact


GGas Insulated Switchgear - Ganz Transelektro Electric Co.

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