ABB SPAJ140C

Description

Product Description

The ABB SPAJ140C is a versatile and widely-used Combined Overcurrent and Earth-Fault Relay from ABB’s comprehensive protection relay portfolio. This relay, the ABB SPAJ140C, is designed to provide primary or backup protection for feeders, motors, transformers, and generators in medium-voltage electrical networks. Its primary function is to monitor phase and earth fault currents, and to initiate a trip command to a circuit breaker when preset current thresholds and time delays are exceeded. The robust design of the ABB SPAJ140C ensures reliable operation in demanding industrial and utility electrical environments.

Product Parameters

The technical specifications for the ABB SPAJ140C protection relay are defined by its protective functions:

• Relay Type: Numerical Combined Overcurrent and Earth-Fault Relay.

• Protection Functions:

  • Three-phase Overcurrent Protection: Definite Time (DT) and/or Inverse Time (IDMT) characteristics for phases (I>, I>>).

  • Earth-Fault Protection: Definite Time (DT) and/or Inverse Time (IDMT) characteristics for earth current (I0>, I0>>).

  • Negative Sequence Overcurrent Protection (unbalance).

• Current Inputs: Three-phase currents (Ia, Ib, Ic) and earth current (I0) via standard 1A or 5A current transformers (CTs).

• Setting Ranges: Wide, adjustable setting ranges for current pick-up values and time delays for all stages.

• Output Relays: Multiple changeover output relays for trip, alarm, and signaling.

• Inputs: Binary inputs for external signals like breaker status or block commands.

• Display & Interface: Backlit LCD for measurement display, event logging, and settings. Front-panel keypad for configuration.

• Communication: Optional communication modules for integration into SCADA systems (e.g., Modbus RTU, IEC 61850).

• Power Supply: Wide-range DC or AC auxiliary supply (e.g., 24-250V DC/AC).

Advantages and Features

The ABB SPAJ140C relay offers significant advantages for electrical system protection:

• Multifunctional and Compact: The ABB SPAJ140C consolidates several essential protection functions into a single, space-saving relay, reducing panel space and simplifying protection schemes compared to using separate overcurrent and earth-fault units.

• High Flexibility and Selectivity: With configurable DT/IDMT curves and extensive setting groups, the SPAJ140C can be precisely coordinated with other protective devices upstream and downstream to ensure selective tripping, minimizing outage impact.

• Advanced Monitoring and Diagnostics: Features like real-time metering (currents, voltages), event recording with time-stamping, and disturbance recording (oscillography) provide valuable data for post-fault analysis and preventive maintenance.

• User-Friendly Operation: The intuitive menu structure on the LCD and keypad allows for easy on-site configuration and commissioning without the need for a PC in many cases.

• Proven Reliability: As part of ABB’s well-established SPAJ family, it has a long track record of dependable performance in diverse applications worldwide.

Application Cases in Industry

This protection relay is fundamental in a wide array of electrical distribution and industrial systems:

• Industrial Plant Medium-Voltage Feeders: Protects outgoing feeders from switchgear to large loads like transformers or motor control centers (MCCs).

• Utility Distribution Substations: Used as a feeder protection relay in secondary substations.

• Motor Protection (Backup): Provides backup overcurrent and earth-fault protection for large high-voltage motors.

• Transformer Incoming/Outgoing Protection: Protects distribution transformers from overload and fault currents.

• Renewable Energy Plants: Used for protecting feeders within solar PV or wind farm collector substations.

Comparisons with Competing Products

When compared to older electromechanical relays or basic electronic relays, the ABB SPAJ140C offers modern, feature-rich advantages:

• Numerical Technology vs. Electromechanical: The ABB SPAJ140C provides much higher accuracy, repeatability, flexible characteristics, and self-diagnostics compared to bulky electromechanical relays with fixed curves and mechanical wear.

• Integrated Multifunction vs. Separate Relays: It replaces multiple single-function relays (e.g., one for phase OC, one for earth fault), saving cost, panel space, and wiring complexity.

• Enhanced Data and Communication: Unlike basic relays, the SPAJ140C offers metering, event logs, and optional communication for remote monitoring and integration into modern control systems—capabilities that are essential for smart grid and Industry 4.0 applications.

• Easier Coordination and Testing: The digital settings and stored curves simplify protection coordination studies. Its self-test features and clear menus also make periodic testing and maintenance more straightforward.

Selection Suggestions and Precautions

Proper application and settings are critical for effective protection:

1. Accurate CT Data and Coordination Study: Before configuring the ABB SPAJ140C, you must have the correct CT ratios and perform a protection coordination study to determine the appropriate current setpoints and time delays for all stages (I>, I>>, I0>, etc.).

2. Select the Correct Auxiliary Supply: Choose the relay variant with the auxiliary voltage (e.g., 110V DC, 220V DC/AC) that matches your station battery or control power supply.

3. Configure Binary Inputs and Outputs Correctly: Map the physical binary inputs (e.g., breaker closed) and outputs (trip, alarm) correctly in the relay’s settings to match your control schematic.

4. Secure the Settings and Document Changes: After commissioning, password-protect the settings to prevent unauthorized changes. Keep a detailed record of all final settings as part of the electrical system documentation.

5. Perform Regular Functional Tests: Integrate the SPAJ140C into the periodic maintenance schedule. Use a primary injection test set to verify the accuracy of the current measurement and the correct operation of the trip output at the designated settings.

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