Switchgear are important nodal points in modern power distribution. Consequently, important is their reliable functioning, a clearly defined switching operation according to specified parameters as well as the protection of personnel and protection against operational interruptions when an overload occurs.
The International Electrotechnical Commission (IEC) has taken up the task of developing the required specifications, with worldwide standardization and further evolving developments. The same applies to IEC 62271-200 – the standard for medium-voltage switchgear panels.
MODUTEC has implemented these requirements and already offers the complete product range of air insulated switchgear today, type-tested according to IEC 62271-200 in terms of
Power Module: that incorporates the Basic VCB, Draw Out mechanism, Shutter Assembly and Spouts that connects the VCB terminals to the Bus Bars. This helps the Panel Builder to build the MV Panel with ease as the rest of fabrication is much simpler to execute and can be configured to customized requirements appropriately.
Basic Kit: that is Type Tested as per IEC 62271-200 with the enclosure to house the VCB with Draw Out mechanism, Shutter Assembly and Spouts that connects the VCB terminals to the Bus Bars with provision to mount the Bus Bars, CTs, PTs and compliant with the Internal Arc requirements. The LV Metering & Protection chamber would need to be further manufactured at the Panel Builder's end, (size being based on the number of meters & relays etc) and fitted on this Basic Kit above the VCB chamber. This helps the Panel Builder to get a Type Tested MV Panel without actually undertaking to do the Tests himself!
The regulation governing medium voltage switchgear is IEC 62271-200, High-voltage switchgear and controlgear, Part 200: A.C. metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV. Regarding non-specific aspects involving switchgear, this Standard often refers to the general Standard for medium voltage switchgear and controlgear, i.e. IEC 62271-1, High voltage switchgear and controlgear Part
Sub-clause 9.1 of IEC 62271-200 (Information to be given with enquiries, tenders and orders) specifies that enquirers requesting an offer or placing an order for metal-enclosed switchgear and controlgear, should not only provide the main electrical characteristics of the system but also the service conditions if different from standard, i.e.
In short, any condition deviating from the normal service conditions or affecting the satisfactory operation of the equipment.
The passing of the following tests is obligatory in order to identify switchgear as type-tested:
Dielectric test to verify the insulation level of the switchgear (tests with rated lightning impulse withstand voltage and rated short-duration power frequency withstand voltage with the specified values depending on the respective rated voltage).
Temperature rise tests to verify the current carrying capacity with rated normal currents. Peak and short-time withstand current tests to verify the dynamic and thermal current carrying capacity of the main and earth circuits; the tests are performed with rated peak short-circuit current or rated short-circuit making current or rated shorttime current or rated short-circuit breaking current.
Switching capacity test to verify the making/breaking capacity of the installed switchgear.
Mechanical function test to verify the mechanical functions and interlocks.
Degree of protection tests to verify the protection against electric shock and foreign objects.
Pressure and strength tests to verify the gas tightness and pressure resistance for gas-filled switchgear.
There is also the possibility of voluntarily certifying switchgear for resistance to internal arc faults and for personal protection. Manufacturers and operators can select the criteria which are relevant to them from the following six criteria and have them tested.
Criterion 1: Doors and covers must not open.Covers and doors remain closed. Limited deformations are accepted.
Criterion 2: Parts of the switchgear must not fly off.No fragmentation of the enclosure, no projection of small parts above 60 g weight.
Criterion 3: Holes must not develop in the accessible sides of the Enclosure up to a height of 2 meters.
Criterion 4: Vertical indicators must not ignitedue to the effect of hot gases.
Criterion 5: Horizontal indicators must not ignite due to the effect of hot gases.
Criterion 6: Earth connections must remain effective& connected to its earthing parts.