ABB NSSM01

Description

Product Description

The ABB NSSM01 is a network synchronization and switching module designed for the ABB Ability™ System 800xA distributed control system. This specialized module is a critical component for applications requiring automatic transfer or synchronization of power sources, such as in power generation, marine, and critical infrastructure. The primary function of the ABB NSSM01 is to monitor the voltage, frequency, and phase angle of two independent AC sources (e.g., a utility grid and a standby generator) and execute a controlled closing command to transfer or parallel the sources when predefined synchronization conditions are met. Its integration within the 800xA system allows for centralized configuration, supervision, and diagnostics of complex power management schemes. The reliability and precision of the NSSM01 are essential for maintaining power continuity and protecting electrical equipment from damage due to out-of-phase closures.

Product Parameters

• Product Type: Network Synchronization and Switching Module.
• System Compatibility: An 800xA Connect product, designed for integration with the ABB System 800xA via a communication interface.
• Primary Function: Automatic synchronization, check synchronization, and automatic transfer of AC power sources.
• Input Signals: Monitors two three-phase voltage sources (typically via voltage transformers – VTs) for parameters: Voltage (V), Frequency (Hz), Phase Angle (ΔΦ).
• Control Outputs: Provides relay outputs to control the closing coil of a circuit breaker or a bus-tie breaker.
• Synchronization Modes: Supports multiple modes including:
  • Auto Synchronization: Closes the breaker at the precise moment when both sources are within preset limits for voltage, frequency, and phase angle.
  • Check Synchronization: Verifies that conditions are acceptable before permitting a manual or other command to close the breaker.
  • Dead Bus / Dead Line Charging: For energizing a de-energized bus or line from a live source.
• Adjustable Parameters: User-configurable limits for voltage difference, frequency difference (slip), phase angle window, and advance time for breaker closure.
• Communications: Connects to the 800xA system via a standard communication interface (e.g., CI854) using a fieldbus like PROFIBUS DP, allowing all parameters, statuses, and events to be visible and controllable from the 800xA operator workplace.

Advantages and Key Features

• High-Precision Synchronization: Employs advanced algorithms to calculate the precise closing instant, minimizing mechanical stress on breakers and generators and preventing damaging power surges.
• Seamless 800xA Integration: As an 800xA Connect product, the ABB NSSM01 is fully configurable and operable from the familiar 800xA engineering and operator environment, providing a unified system view.
• Enhanced Power System Safety: Prevents unsafe closing operations by continuously monitoring and enforcing synchronization limits, a critical feature for personnel and equipment protection.
• Flexible Application Configuration: Supports various common power management schemes (e.g., mains failure auto transfer, peak shaving, generator paralleling) through its configurable modes and logic.
• Comprehensive Diagnostics and Logging: Provides detailed event logging and diagnostics, which are accessible through 800xA, aiding in troubleshooting and post-event analysis of transfer operations.

Application Case Studies

• Hospital Emergency Power System: Upon a utility failure, the ABB NSSM01 monitors the decaying grid and the starting standby generator. Once the generator is stable and within synchronization limits with the hospital’s internal bus, the module commands the Automatic Transfer Switch (ATS) to close, restoring power with minimal disruption to critical loads.
• Marine Power Management System (PMS): On a vessel with multiple diesel generator sets, the NSSM01 modules are used to synchronize an incoming generator to the live shipboard bus before closing the breaker, allowing for seamless load sharing. It also manages bus transfer during blackout recovery.
• Industrial Plant Cogeneration Facility: For a plant with a gas turbine generator operating in parallel with the utility grid, the module continuously performs check synchronization. It ensures that if the plant needs to reconnect to the grid after an islanding event, the re-closure is perfectly synchronized to avoid severe disturbances.

Comparison with Competing Products

The ABB NSSM01 competes with other dedicated synchronization equipment such as the Siemens 7VE61/7VE66 synchronizing device or the Basler SCP-250 Sync-Check Relay. Compared to these standalone hardware relays, the key advantage of the NSSM01 is its deep integration into the ABB 800xA DCS. This allows for centralized parameter management, remote operation from any workstation, and integration of synchronization logic with broader plant control strategies. Standalone devices may offer robust performance but operate as isolated “black boxes.” Compared to implementing synchronization logic in a standard PLC, the NSSM01 offers pre-certified, application-specific functionality with higher precision and safety integrity, reducing engineering risk and validation time.

Selection Suggestions and Precautions

• Selection Suggestion: Select the ABB NSSM01 for power switching and synchronization applications within a System 800xA environment where centralized control, advanced diagnostics, and integration with process automation are required. It is ideal for automatic transfer schemes, generator paralleling, and any application where precise breaker closing is safety or equipment-critical.
• Precautions:
  1. Accurate VT Connections and Scaling: The module’s performance depends entirely on accurate voltage signals. Ensure the voltage transformers (VTs) are correctly connected, and the scaling parameters in the NSSM01 configuration exactly match the VT ratios. Incorrect scaling will lead to faulty synchronization.
  2. Breaker Closing Time Setting: The advance time parameter (the time it takes the breaker mechanism to close after receiving the command) must be measured and set accurately for the specific breaker being controlled. An incorrect advance time will cause out-of-phase closing.
  3. Communication and System Integration: Proper configuration of the communication link (PROFIBUS address, data mapping) between the NSSM01 and the 800xA system is crucial for remote monitoring and control. This requires expertise in both the module and 800xA engineering.
  4. Testing and Commissioning: Synchronization schemes must be thoroughly tested during commissioning using secondary injection test sets to simulate various source conditions (voltage difference, frequency slip) and verify correct operation and timing. Never commission based on configuration alone.

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