GE MVAJ Trip Relay: Protection and Control Core

GE MVAJ Trip Relay: Protection and Control Core

MVAJ 05/10/20 Series Trip and Control Relays: Providing Reliable Execution Interface for Power System Protection

In the protection architecture of power systems, protective relays (such as overcurrent, differential, distance protection, etc.) are precision measuring devices, and their contacts usually do not have the large capacity required to directly operate circuit breaker trip coils. Meanwhile, complex protection schemes may require the simultaneous tripping of multiple circuit breakers or the implementation of control functions such as signaling and interlocking. To address this core issue, GE Vernova has launched the MVAJ 05/10/20 series of trip and control relays. This series is based on mature rotary armature technology and aims to provide a highly reliable, flexible, and fast execution interface between protective relays and circuit breakers.

Product Overview: Strong Support for Protection Systems

The MVAJ series relay is essentially an auxiliary relay, but its design goals are far from comparable to ordinary intermediate relays. It is specifically designed for direct operation of circuit breaker trip coils and has the following core values:

High contact capacity: It can safely connect and disconnect large inductive loads such as circuit breaker trip coils, with a contact capacity of up to 7500 VA/W (3 seconds), far exceeding the output capacity of ordinary protective relays.

Multi contact configuration: Provides models with up to 20 contacts, capable of simultaneously tripping multiple circuit breakers, issuing multiple signals, or implementing complex interlocking logic.

High speed action: The tripping type relay has an action time of less than 8-10ms (depending on the model) to ensure that the fault can be quickly isolated.

High reliability: Adopting a sturdy rotating armature design, it has extremely high mechanical stability and electrical life.

Strong anti-interference ability: The specially designed high load configuration gives it natural immunity to the discharge current of the DC system's ground capacitor, making it very suitable for distributed trip circuits.

Model selection and application scenarios

The MVAJ series offers a wide range of model choices based on the number of contacts and reset methods to meet different application requirements.

1. Classify by the number of contacts

Model Series Contact Quantity Shell Size Typical Applications

MVAJ 05 5 contacts Midos Size 2 small switchgear, single circuit breaker control

MVAJ 10 contacts Midos Size 2 standard line protection, transformer protection

MVAJ 20 contacts Midos Size 4 complex busbar protection, multiple circuit breaker tripping

2. Classify by reset method

The MVAJ series provides multiple reset mechanisms to meet different control logic requirements:

Reset type, applicable models, characteristics and applications

The self resetting MVAJ 051, 101, 102 will automatically reset the relay when the start signal disappears. Suitable for line protection and general signal indication that require automatic reclosing. MVAJ 102 is a special model with a 2.5-second delay self reset.

After the MVAJ 053, 103, 203 relay is manually reset and mechanically held, it must be manually reset through the buttons on the panel. Suitable for anti bounce relays that require fault memory, non electric protection of transformers, etc., used as a lockout relay.

Electric reset MVAJ 054, 104, 204 requires an independent reset voltage to be applied in order to reset. Suitable for remote reset or automation system control.

Manual/Electric Reset MVAJ 055, 105, 205 offer both manual and electric reset modes, providing maximum operational flexibility.

Deep analysis of core technical characteristics

1. High load configuration and capacitor discharge tolerance

This is one of the most prominent technological advantages of the MVAJ series. In DC control circuits, long cables have distributed capacitance to ground. When a grounding fault occurs, the energy stored in the capacitor will instantly discharge to the relay coil, which may cause low load relays to malfunction.

High load configuration (factory default): MVAJ relays are set to high load mode at the factory. In this mode, the relay has a higher minimum operating current, allowing it to withstand discharge surges from a 10 μ F capacitor charging to 120% rated voltage (for ≤ 125V specifications) or 100% rated voltage (for 220/250V specifications) without misoperation. This makes it particularly suitable for distributed trip circuits or situations where protective contacts are far away from the relay body.

Low load configuration: The relay can be switched to low load mode by removing the external connector between terminals 22 and 24. At this time, the relay is more sensitive to the starting current and is suitable for local control scenarios where the starting contact is nearby. Its capacitance discharge tolerance is 1 μ F.

2. Load shedding and energy-saving circuit design

In order to reduce power consumption and protect the coil after action, the MVAJ series has designed an intelligent load shedding circuit: