Category: GE

The MVAJ 11 to 34 range complements the more cost-effective range of MVAJ 051 to

MVAJ 205 tripping relays catering for the preferences of historical users.

MVAJ general characteristics can be found in table 1 that includes information on how

relay burden is modified at, or just after operation. ‘Economy’ indicates that the burden

reduced to a low value.

Instantaneous cut-off is a feature of some hand and electrical-reset elements and

the burden to zero, whilst others incorporate a time delay to enable series elements

operate. This time delay is 40 ms to 60 ms in all cases, except that of  type MVAJ 26

the delay is 2 s. All low burden relays are suitable for AC or DC operation. All high

relays are for DC operation only.

Types MVAJ 23. 25 High Burden Tripping Relays

with Instantaneous Cut-off

These relays incorporate a break contact in series with the

operate coil. Located on the main contact stack, it is arranged to

break the coil circuit once the relay mechanism has completely

operated. This reduces the relay burden to zero as soon as

mechanical latching of the contacts has occurred.

MVAJ 10. MVAJ 20

When configured for high burden applications, the burden is

either cut off or is economised to a low figure after a 40-60 ms

time delay. Due to the greater minimum operating current, the

high burden application also permits the use of supervision relays

such as type MVAX 11. where the wiring is at risk. The 40- 60 ms

time delay ensures reliable operation of series elements such as

type MCAA repeat relays.

Type MVAJ 102 relay is specifically designed for applications

requiring a tripping relay which is self-resetting after a nominal

delay of 2.5 seconds. This relay may be used, for example, for

inter-tripping between higher voltage and low voltage circuit

breakers of a large 3-phase power transformer.

This may become necessary when the high voltage circuit

breaker is tripped after a heavy internal fault by protection

which cannot conveniently provide an auxiliary contact with a

dwell time long enough to ensure correct tripping of the low

voltage circuit-breaker.

Typically, the relay is initiated by transformer protection, such as

overall protection, restricted earth fault and Bucholz relays, in

arrangements where both the HV and LV circuit-breakers are to

be tripped simultaneously.

The HV breaker may be expected to trip more quickly than the LV

breaker so the tripping signal is maintained by the delayed reset.

This ensures complete clearance by the LV circuit-breaker, even

though the fault may have been cleared largely by the HV breaker

and the protection has started to reset.

High Burden Application

These relays, supplied as high burden, are suitable for use in high

security circuit-breaker tripping circuits. The high burden provides

greater immunity to capacitance discharge currents, which can

result at the inception of an earth fault on battery wiring. This

makes the relays particularly suitable for use in distributed

tripping or control relay contact logic schemes, where the

initiating contact may be remote from the relay.

MVAJ 05

When configured for high burden applications, the burden is

either cut off at operation or is economised to a low figure

instantaneously.

Low Burden Application

These relays are suitable for general applications where the

initiating contact is located close to the relay. When configured

for low burden applications, by removing the external link from

terminals 22 and 24. the burden is either cut off during operation

or is economised to a low figure instantaneously.

Models Available

• Trip relays

Trip relays possess a standard hand-reset flag and operate within 10 ms.

Table 1 shows  the trip relay versions available

• Control relays

Control relay variants of each trip relay are available. These relays operate within

approximately 15 ms

All relays configured for high burden applications are suitable for DC operation only

Applications

Self-reset relays reset when the initiating signal is removed,

making them suitable for use as trip relays in auto-reclose

schemes and also for general flagging purposes. Hand-reset relays

require manual resetting, making them effective lockout relays

which are commonly used to trip circuit-breakers associated with

transformers. Electrical-reset relays require a voltage to be

applied to the unit to reset the contacts. These relays may be

used in auto-reclose schemes, or where remote resetting of the

relay is required.

Trip Relay

With the exception of the MVAJ 102 time delayed self-reset

relays, all trip relays are suitable for either low burden or high

burden applications.

Protective relays are precise measuring devices, the contacts of which

should not be expected to switch large electrical loads.

In some cases, the protective relay can trip a circuit- breaker directly,

or according to coil rating and the number of circuits to be energised.

The MVAJ relay interfaces with the protection to provide: higher contact

additional contacts for tripping multiple circuit-breakers, control functions,

signalling interlocking.

The MVAJ range comprises very reliable hinged armature relays designed

to operate circuit-breaker trip coils. Built to very high specifications, the

MVAJ range a highly flexible and reliable link between the protective relays

and the circuit-breakers.

Low Burden Application

These relays are suitable for general applications where the

initiating contact is located close to the relay. When configured

for low burden applications, by removing the external link from

terminals 22 and 24. the burden is either cut off during operation

or is economised to a low figure instantaneously.

Applications

Le transmetteur de débit pour liquide AquaTrans

AT868 est un système de mesure de débit à

ultrasons complet des liquides suivants:

• Eau potable

• Eaux usées

• Eaux d‘égout

• Eaux de rejet

• Eau traitée

• Eau de refroidissement et de chauffage

• Autres liquides

Caractéristiques

• Mesure du débit non intrusive et économique

• Installation et configuration simples

• Adapté à un large éventail de tailles de conduites

et de matériaux

• Adapté aux conduites à revêtement interne

• Version deux canaux/deux cordes disponibles

• Vitesse d‘écoulement , débit volumétrique et

débit totalisé

• Clavier interne pour la programmation sur site

AT868 Caractéristiques techniques

Performance

Types de fluides

Fluides acoustiquement conducteurs, y compris la plupart

des liquides propres et de nombreux liquides chargés ou

contenant des bulles de gaz. La fraction de vide maximum

dépend du transducteur, de sa fréquence, de la longueur de

la trajectoire et du trajet acoustique des conduites.

Tailles de conduite

• Transducteurs « clamp-on » : 12.7 mm à 7.6 m et plus

• Transducteurs mouillés : 25.4 mm à 5 m et plus

Épaisseur de paroi de conduite

Jusqu‘à 76.2 mm

Key Benefits

• Reliability enhancements through real-time detection of unstable system behavior

and isolation of the affected system ensuring your most critical infrastructure stays

online until normal system operation is restored

• Improve Resiliency by providing a system that can self-isolate from the affected grid

and continue to support its loads independently for desired periods of time

• Energy Cost Reduction through a solution that can efficiently manage and optimize

your energy resources based on real-time energy market prices, operational costs and

energy resource mix

• Increase Revenue providing the capability to your system to provide ancillary services

to the grid such as Frequency Control, Reserve Capacity, and Demand Response

• Energy Security by effectively controlling, monitoring and optimizing your local energy

assets reducing your need to rely on a centralized supply

• High percentage of Renewables integration through an energy management solution

that will support the transition to new renewable energy targets and policies

• Reduce Emissions by optimal dispatch and management of your energy resource mix

Solutions and Services

• Engineering and Consulting Services

• Controls and HMI Development

• GridNode Microgrid Control and Automation Functions

• Protection, Control, Automation, and Communications Products

• Testing incl. Hardware-In-the-Loop Testing

• Integration and On-site Services

• Cyber Security Solutions

• Maintenance and Support

Multi-terminal HVDC systems and DC Grids

Challenge

Interconnect three or more regions and power systems to facilitate power

exchange and trading, and to provide added system security, efficiency and

flexibility to the benefit of the overall grid.

GE’s solution

GE’s HVDC enables the interconnection of multiple HVDC converters

providing controllability of power flow and facilitates the future expansion

into HVDC grids.

Benefits include

• Better management and integration of renewable energy generation

• Increases grid security

• Enables cross border energy trading

• Provides more efficient network by reducing reliance on thermal generation

Connecting Renewable Generation

Challenge

Bring power from remote renewable sources to load centres

GE’s solution

GE’s HVDC LCC and VSC are amongst the most economical and feasible

solutions for connecting renewable generation applications, such as wind,

hydro and solar power. GE’s solution gives full control and flexibility in

managing the power flow from the intermittent and variable generation to

the load.

Benefits include

• Provides a low loss solution, with the most efficient method of

transmission technology

• Enables the controllability of intermittent power

• Improves environment impact as a result of the smaller towers and right

of way requirements

• Increasing power capabilities up to 3 times more than AC circuits

HVDC Applications

Connecting Offshore Wind

Challenge

Bring power from distant wind farms to the onshore grid.

GE’s solution

GE’s HVDC VSC technology is the most economical and feasible solution for

connecting submarine cable applications, such as offshore wind farms. GE’s

solution gives full control and flexibility in managing the intermittent and

variable generation.

Benefits include

• Provides a low loss solution, with the most efficient method of

transmission technology

• Enables the controllability of intermittent power

• Optimizes the use of submarine cables

Infeed Urban Areas

Challenge

To get power into congested cities to address increasing demand, lack of

power highways and difficulties with establishing rights of way for a new grid.

GE’s solution

GE’s VSC HVDC technology is ideally suited to provide controllable

and efficient power into congested areas where small footprint and

environmentally acceptable solutions are essential.

Benefits include

• Minimizes the visual impact of the power infeed on the local landscape

• Provides high levels of power injected directly to where it is needed

• Manages fault propagation providing a power “firewall” between the

interconnected networks

• Provides lowest loss solution, with the most efficient method of

transmission technology