Alstom KCEU142 Digital Protection Relay

Introduction to ALSTOM KCEU142

The ALSTOM KCEU142 is a sophisticated numerical protection relay from the esteemed K-Series (legacy GE/Alstom/Areva line).

It is specifically engineered for directional overcurrent and sensitive earth fault protection.

Unlike standard overcurrent relays, the KCEU142 incorporates a wattmetric characteristic, making it the ideal choice for insulated power systems or networks earthed through an arc-suppression (Petersen) coil.

As a numerical device, it offers far greater precision, communication capabilities, and diagnostic tools than older electromechanical models, while maintaining the “withdrawable” design that Alstom is famous for.

Technical Parameter Table

Related Models & Series

The KCEU142 is part of a tiered family of protection solutions:

KCGG 142: Non-directional three-phase overcurrent and earth fault.

KCEG 142: Standard directional overcurrent and earth fault.

KCEU 242: Similar to 142 but with additional hardware or specific I/O configurations.

KCGU Series: Non-directional versions with wattmetric sensitivity.

Product Advantages and Features

Wattmetric Protection: Specifically designed to detect low-level earth faults in systems where fault currents are significantly masked by capacitive current.

Synchronous Polarization: Maintains directional sensitivity even during a complete voltage collapse (fault near the busbar) using memory voltage.

Integrated Disturbance Recorder: Captures waveform data during a trip, allowing engineers to perform post-fault analysis without external oscillographs.

Withdrawable Design: The “K-Series” case allows the relay to be pulled out for testing or replacement without disturbing the panel wiring, automatically shorting CT circuits.

Programmable Logic: Allows users to define custom logic for blocking, tripping, or interlocking via the front panel or PC software.

Application Cases

Insulated Neutral Systems: Detecting high-impedance earth faults where standard current-based relays would fail to trigger.

Petersen Coil Earthed Networks: The wattmetric function accurately identifies the faulty feeder by measuring the active component of the residual power.

Radial and Ring Feeders: Providing selective directional tripping to ensure only the faulted section of a network is isolated.

Industrial Microgrids: Managing protection in environments with distributed generation where fault current flow can change direction.

Installation and Maintenance

Installation

Mounting: Ensure flush mounting on a clean, vibration-free panel. The case requires a specific cutout (Standard Size 4).

Grounding: The case must be connected to a dedicated protective earth terminal to ensure the internal noise filters work correctly.

Polarity: Correct VT (Voltage Transformer) polarity is critical for the directional and wattmetric functions to operate.

Maintenance

Self-Diagnostics: The relay performs a self-test every few seconds. Check the “Healthy” LED (Green) regularly.

Static Precautions: When withdrawing the module, always touch the metal case first to discharge static electricity before touching internal PCBs.

Secondary Injection: Use the MMLG test block (if installed) to perform annual secondary injection tests to verify the pick-up thresholds.

KCEU142

Unique Product Description

The ALSTOM KCEU142 is often described by field engineers as the “brain of the feeder.”

While basic relays simply see “too much current,” the KCEU142 understands the geometry of the fault. By analyzing the phase relationship between voltage and current, it can distinguish between a fault “behind” the relay and one “in front” of it.

Its ability to calculate wattmetric power makes it a specialized surgeon in complex earthing environments, cutting away only what is necessary to keep the rest of the grid alive.