ALSTOM AM164

Description

Product Description
The ALSTOM AM164 is a specialized and critical Trip Amplifier Module designed for the Alstom (now part of GE or part of the legacy Alstom T&D portfolio) MICOM P14x series of protection relays, widely used in electrical power transmission and distribution systems. This module is not a general-purpose PLC part but a dedicated component for power system protection. Its primary function is to act as a threshold detector and signal conditioner for critical electrical parameters such as overcurrent, overvoltage, frequency, or temperature. The ALSTOM AM164 monitors analog input signals from current transformers (CTs) or voltage transformers (VTs), compares them to pre-set pickup values, and provides a clean, isolated digital output to trigger a circuit breaker trip or an alarm when the threshold is exceeded. For protection engineers maintaining high-voltage substations or industrial power systems, the AM164 amplifier is a fundamental building block for implementing custom or additional protection schemes within the versatile MICOM relay platform. Its reliability and precision are essential for ensuring the selective isolation of faults, thereby maintaining grid stability and equipment safety.

Product Parameters

• Module Type: Trip Amplifier / Threshold Detection Module.
• Product Family: Alstom (GE) MICOM P14x Protection Relay Series (e.g., P141, P142, P143).
• Function: Monitors a single analog input channel (current or voltage) and provides one or more programmable relay outputs based on configurable thresholds and time delays.
• Input Types: Typically accepts signals from:
  • Current Transformers (CTs): 1A or 5A secondary.
  • Voltage Transformers (VTs): 110V or 120V line.
  • DC signals (e.g., from temperature sensors).
• Outputs: Form-C relay contacts (changeover contacts) for tripping, alarming, or control.
• Configuration: Setting of pickup values, time delays (definite or inverse time), and output relay assignment is done via DIP switches or potentiometers on the module itself, depending on the variant.
• Mounting: Plugs into a dedicated slot within the MICOM P14x relay case.
• Power Supply: Powered by the internal supply of the host MICOM relay.

Advantages and Features

• Enhanced Protection Flexibility: Allows engineers to add custom protection functions (e.g., a specific overvoltage stage, negative sequence current detection) to a standard MICOM relay without needing a completely new device.
• High Reliability and Simplicity: As a hardware-based, analog/digital module, it provides a very robust and deterministic response, independent of the relay’s main software CPU, which can be an advantage for critical hardwired trips.
• Easy Configuration and Testing: Settings are visually accessible on the module. Its operation can be easily tested by injecting a signal and verifying the output relay operation.
• Isolation: Provides galvanic isolation between the high-voltage instrument transformer circuits and the relay’s low-voltage logic and output circuits, enhancing safety and noise immunity.
• Proven in Service: Part of the widely deployed and trusted MICOM P14x series, known for its reliability in protecting feeders, transformers, and motors worldwide.

Application Cases in Application Fields

• Electrical Substations (Distribution Feeder Protection): Used in a P141 relay to provide a dedicated 51N (time-overcurrent earth fault) element for a medium-voltage feeder, with the AM164 monitoring the residual current from a core-balance CT.
• Industrial Plant Power Systems (Motor Protection): Installed in a P143 motor protection relay to add a separate 49 (thermal overload) element based on a direct temperature signal from embedded motor RTDs (Resistance Temperature Detectors).
• Renewable Energy (Generator Protection): Added to a P142 relay on a small hydro or biogas generator to implement an 81 (frequency) protection stage for over/under frequency trip.
• Critical Busbar Protection: Used to create a simple, dedicated overvoltage (59) or undervoltage (27) protection scheme for a critical busbar section.

Comparisons with Competing Products
The ALSTOM AM164 is specific to the MICOM P14x ecosystem. Its functional competitors would be:

• Other Relay Manufacturer’s Add-On Modules: Similar modules from Siemens (7SJ series), Schweitzer Engineering Laboratories (SEL) (auxiliary cards), or ABB (SPAJ modules). The AM164‘s advantage is seamless integration and programming familiarity for users of the MICOM platform.
• External Hardwired Relay: An alternative would be a standalone, discrete protection relay (e.g., an overcurrent relay). The AM164 integrates the function into the existing relay panel, saving space, wiring, and providing a unified interface.
• Software-Based Function in a Numerical Relay: Modern numerical relays can often program these functions in software. The AM164 offers a hardware-based, easily verifiable solution that is independent of the main CPU’s software integrity, which is sometimes preferred for specific critical trips.

Its key advantage is providing a certified, tested, and simple hardware solution within a well-established protection relay family.

Selection Suggestions and Precautions

1. Host Relay Compatibility: Confirm that your specific MICOM P14x relay model (e.g., P141, P142) has an available slot and supports the AM164 module. Consult the relay’s hardware manual.
2. Exact Function and Settings: Determine the precise protection function (e.g., 50, 51, 27, 59), the input signal type (CT/VT ratio), and the required pickup and time delay settings before ordering and configuring the module.
3. Wiring and CT/VT Safety: Adhere to strict electrical safety practices when wiring to CT and VT circuits. Never open-circuit a CT secondary – it can produce lethal voltages. Ensure VTs are properly fused.
4. Testing and Commissioning: After installation, the AM164 function must be thoroughly tested as part of the overall relay commissioning. This involves primary injection testing to verify the pickup accuracy and timing.
5. Obsolescence Note: The MICOM P14x series is a mature product line. Ensure availability of spares for long-term support. For new projects, consider the migration path to newer Alstom/GE Grid Solutions relays like the MiCOM Px4x series.

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