ABB SPAJ 110 C Earth-fault relay

ABB SPAJ 110 C Earth-fault relay

Product overview

SPAJ 110 C is a non directional grounding fault relay designed for direct grounding or low resistance grounding power systems, used for selective grounding fault protection, and can be used as primary or backup protection. This relay consists of two protection stages: a low setting overcurrent stage (I ₀>) and a high setting overcurrent stage (I ₀>>). The low setting stage can choose between timed or inverse timed characteristics, while the high setting stage only supports timed characteristics and is suitable for ground fault protection of equipment such as feeders, transformers, generators, and motors.

Core functions

Protection function

Low setting neutral line overcurrent stage (I ₀>): Supports timed or inverse time characteristics (compliant with BS 142 and IEC 60255 standards, providing four types of curves: normal inverse time, extraordinary inverse time, extreme inverse time, and long-term inverse time).

High setting neutral line overcurrent stage (I ₀>>): Only supports timed characteristics and can be set to exit operation (∞).

The output relay function can be freely configured, supporting external locking signal input, and can be used in conjunction with residual voltage relays to achieve locking/unlocking operations.

Monitoring and recording

Digital display of set values, measured neutral current, memorized fault values, etc.

Record data such as maximum measured current, number of startups in each stage, and recent startup duration.

Communication and Self Inspection

The serial interface supports connecting fiber optic buses, substations, and network control systems.

Continuous self-monitoring function, automatically diagnose hardware and software faults, and trigger alarms when faults occur.

Specification parameters

Current input

Rated current (I ₙ): 1A or 5A (selected through terminals 25-27 or 25-26).

Thermal endurance: It can continuously carry 4A at 1A rated current and 20A at 5A rated current.

Dynamic current tolerance (half wave value): 250A at 1A and 1250A at 5A.

Output contact

Trip output (65-66, 68-69): rated voltage 250V AC/DC, continuously carrying 5A, can be connected and carrying 30A within 0.5s.

Signal contacts (70-71-72, etc.): rated voltage 250V AC/DC, continuously carrying 5A.

Auxiliary power supply

Module type SPTU 240 S1:80... 265V AC/DC.

Module type SPTU 48 S1:18... 80V DC.

Power consumption: about 4W statically and about 6W during operation.

Setting Range

Low setting current (I ₀>): 0.1... 0.8 × I ₙ.

High setting current (I ₀>>): 0.1... 4.0 × I ₙ or ∞ (exit).

Action time: 0.05... 100 seconds (divided into three levels).

Working principle

The relay measures the neutral line current (I ₀) through a current transformer. When the current exceeds the starting value of the low setting stage (I ₀>), the relay starts and acts after reaching the set action time; The high tuning stage (I ₀>>) is the same, but only supports timed features. The external locking signal can be input through terminals 10-11 to lock any stage or lock two stages simultaneously. When a fault occurs, the relay outputs an alarm signal, a trip signal, or activates an external automatic reclosing relay according to the configuration.

Key advantages

High flexibility: The output relay can be freely configured to adapt to different application scenarios; Support the implementation of complex protection logic in conjunction with residual voltage relays.

Strong reliability: With continuous self-monitoring function, it can detect hardware and software failures and trigger alarms, ensuring the reliability of the relay itself.

Easy to integrate: Supports serial communication interface, can be connected to fiber optic bus and control system, convenient for remote monitoring and data transmission.

Accurate measurement and recording: Digital display of key parameters, recording of fault data, facilitating fault analysis and system optimization.