Description
Product Overview
The ABB S-093N 3BHB009885R0021 is a highly sophisticated and critical power converter module, forming the core of the excitation system for large synchronous machines, specifically designed to work within ABB’s UNITROL® 1000 series of Automatic Voltage Regulators (AVR) and static excitation systems. This unit, often referred to as a thyristor bridge or power stack, is the high-power, controlled rectifier assembly responsible for converting the AC input power (typically derived from an excitation transformer or a permanent magnet generator — PMG) into precisely regulated DC output power to supply the field winding of a synchronous generator or motor. Its primary function is to execute the rapid and accurate control commands from the UNITROL® 1020 or 5000 series AVR controller, varying the DC field current to maintain constant generator terminal voltage, control reactive power (VArs), and ensure system stability under all load and network conditions.
More than a simple rectifier, the ABB S-093N is an integrated power assembly engineered for maximum reliability and performance. It houses multiple high-power thyristors (SCRs) arranged in a fully controlled bridge configuration, along with associated snubber circuits, gate drive units, cooling elements, and monitoring sensors. The suffix
3BHB009885R0021identifies the specific manufacturing and configuration order code. Its operation is fundamental to the dynamic performance of the generator: it must respond within milliseconds to AVR commands to counteract load changes, support the grid during faults, and implement protective field forcing or field suppression. For operators of power plants, industrial generators, and large synchronous motor drives, the ABB S-093N represents the robust and intelligent «muscle» of the excitation system, directly translating control intelligence into the magnetic force that governs the electrical output and stability of the synchronous machine.Technical Specifications
|
Parameter Name
|
Parameter Value
|
|---|---|
|
Product Model
|
ABB S-093N 3BHB009885R0021
|
|
Manufacturer
|
ABB
|
|
Product Series
|
Part of the UNITROL® Static Excitation System
|
|
Product Type
|
Thyristor Bridge / Power Converter Module
|
|
Input Configuration
|
Typically 3-phase AC input, voltage and current ratings specific to the generator excitation requirements (e.g., from an excitation transformer).
|
|
Output Configuration
|
DC output to the generator/synchronous motor field winding. Rated for high continuous and short-term field forcing currents.
|
|
Thyristor Configuration
|
Six-pulse fully controlled bridge (or possibly twelve-pulse in dual-bridge systems), utilizing high-power, phase-controlled thyristors (SCRs).
|
|
Cooling Method
|
Forced air cooling (with integrated fans) or liquid cooling, depending on the power rating and design.
|
|
Control Interface
|
Receives firing pulses from the AVR’s firing card assembly via fiber-optic or other isolated links for precise timing and electrical isolation.
|
|
Protections & Monitoring
|
Includes built-in protection: overcurrent, overtemperature, loss of cooling, snubber circuit monitoring, and individual thyristor status monitoring (via BOD — Breakover Diode).
|
|
Field Discharge Circuit
|
Integrated or associated with external field discharge resistor and crowbar circuit for safe energy dissipation during rapid field suppression.
|
|
Enclosure
|
Rugged, metal enclosure designed for panel or floor mounting, with appropriate IP protection for its environment.
|
|
Agency Approvals
|
Designed to comply with international standards for power electronic equipment (IEC, IEEE, UL).
|
|
Communication
|
Status and alarm signals (temperature, health) communicated back to the AVR controller via hardwired contacts or digital communication.
|
Key Features and Advantages
ABB S-093N 3BHB009885R0021 is distinguished by its high power density, robust construction, and advanced protection. Engineered for continuous, demanding service, it utilizes high-grade, industrial power thyristors and is designed with optimal thermal management (e.g., large heat sinks, efficient cooling) to ensure reliable operation at full rated current without derating. Its robust mechanical design withstands the vibrations and thermal cycles inherent in power plant environments. The integration of comprehensive self-protection and monitoring features—such as overtemperature sensors, loss of cooling detection, and individual thyristor monitoring via Breakover Diodes (BOD)—allows for predictive maintenance and prevents catastrophic failures by enabling the AVR to take preemptive action (e.g., alarm, reduce load, or initiate a safe shutdown).
Precise and fast dynamic response is critical to its function. The thyristor bridge, under the command of the advanced UNITROL® AVR, can adjust the field current with extremely fast response times. This enables the generator to maintain tight voltage regulation during large load steps, provide instantaneous reactive power support to the grid (enhancing voltage stability), and execute rapid field forcing for transient stability enhancement or rapid field suppression (inverse excitation) during internal faults. The use of fiber-optic firing pulse transmission ensures perfect electrical isolation between the low-voltage control electronics (AVR) and the high-power stage, eliminating noise issues and enhancing control reliability.
Modularity and serviceability are designed into the system. The power stack is often constructed in a modular fashion, allowing for easier maintenance. Individual thyristor assemblies or gate drive units can often be replaced without removing the entire bridge from service. Clear status indicators and accessible test points facilitate troubleshooting. As a core component of the ABB UNITROL® system, the S-093N is perfectly matched and optimized to work with ABB’s AVR controllers, ensuring seamless integration, optimized performance, and access to ABB’s global service network for support, spares, and upgrades. For generator owners, it delivers the power, precision, and reliability needed for high-performance excitation in the most demanding grid-connected or island-mode applications.
Application Areas
The ABB S-093N 3BHB009885R0021 thyristor bridge is a key component in static excitation systems for a wide range of large synchronous machines.
Its primary application is in the excitation systems of utility-scale generators:
-
Thermal Power Plants: For steam turbine-driven generators, providing the field power for voltage and VAR control.
-
Hydroelectric Power Plants: For both large and small hydro generators.
-
Gas Turbine and Combined-Cycle Power Plants: For the main generator excitation.
It is also used in industrial power generation for large co-generation plants in industries like pulp & paper, chemicals, and metals. Furthermore, it is applied in synchronous condenser installations, where the machine is used solely for reactive power support to the grid, requiring precise and fast control of field current. For large synchronous motor drives in applications like compressors, mills, and ship propulsion, the S-093N provides the controlled excitation for the motor’s field winding. Essentially, this power converter is employed wherever a high-power, fast-response, and highly reliable static excitation source is required for a synchronous machine, typically in applications ranging from 10 MVA to several hundred MVA.
Related Products
-
ABB UNITROL® 1020 or 5000 AVR Controller: The digital regulator that provides the firing commands to the S-093N thyristor bridge.
-
Excitation Transformer: Steps down the generator terminal voltage (or uses another AC source) to provide the appropriate AC input voltage to the thyristor bridge.
-
Field Circuit Breaker and Discharge Resistor: For connecting/disconnecting the field and safely dissipating the magnetic energy during a trip.
-
AVR Firing Pulse Unit / Fiber-Optic Interface: The module that converts the AVR’s logic signals into isolated firing pulses for the thyristors.
-
ABB UNS0880a/UNS0881a (Gate Decks / Firing Modules): Often the specific gate drive and monitoring units attached to the thyristors within the S-093N assembly.
-
Cooling System Components: Fans, filters, and possibly water cooling units for the thyristor heatsinks.
-
ABB Ability™ / Optimize™ Products: Digital solutions for condition monitoring and performance optimization of the excitation system.
-
Measurement Transformers (CTs, VTs): For providing signals to the AVR controller.
Reviews
There are no reviews yet.