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MVAJ 11 to 34 tripping and control relays0 pages
PROTECTION PRODUCT SOLUTIONS
MVAJ11 to 34
Tripping and control relays
The MVAJ 11 to 34 range
complements the more
cost-effective range of
MVAJ 051 to MVAJ 205
tripping relays.
Cater for the preferences
of historical users
Type MVAJ relays may broadly be divided into three groups:
• High burden tripping relays complying with ESI 48-4 Class EB2
• Low burden tripping relays which comply with ESI 48-4 Class EBl
• Control relays which meet the requirements of National Grid Company SPEC.NGTS
2.19:1996
Table 1 lists the general characteristics
and includes information on how the
relay burden is modified at, or just after
operation. 'Economy' indicates that the
burden is reduced to a low value.
Instantaneous cut-off is a feature of
some hand and electrical-reset elements
and reduces the burden to zero, whilst
others incorporate a time delay to enable
series elements to operate. This time
delay is 40 ms to 60 ms in all cases,
except that of type MVAJ 26 where the
delay is 2 s. All low burden relays are
suitable for AC or DC operation. All high
burden relays are for DC operation only.
HIGH BURDEN TRIPPING TYPES
MVAJ 21, 23, 24, 25, 26, 27, 28
and 29
These relays are suitable for use in high
security circuit breaker tripping circuits.
In particular they can be used in
distributed tripping or control relay
contact logic schemes, where the
initiating contact may be remote from the
relay. The relays have a high burden
which is either cut-off at operation or
economised to a low figure, either
instantaneously or after a time delay.
The high burden provides immunity to
capacitance discharge currents, which
can result at the inception of an earth
fault on battery wiring and immunity to
the subsequent leakage current.
The high burden also permits the use of
supervision relays such as type MVAX
where the wiring is at risk and provides
reliable operation of series elements such
as repeat relays type MCAA. For the latter
purpose, type MVAJ relays can be
provided with a time delayed
economising feature.
CUSTOMER BENEFITS
• High speed operation
• High and low burden
alternatives
• Models surge proof against
high capacitance discharge
currents in the dc supply
system, are available
• Control relays immune to AC
can be supplied
Grid-SAS-L3-MVAJll-34-25l4-20l3_l2-EN. Information contained in this document is indicative only. No representation or warranty is given or should be
relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided
without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Alstom contributes to the protection of the environment. This leaflet is printed on environmentally friendly paper.
ALSTOM
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