Description
ABB PCD235B101 (Part No.: 3BHE032025R0101) Product Specification
Product Overview
This item is a dedicated master CPU module for Unitrol1000/Unitrol5000 excitation systems. It is not a standalone protection relay but an integrated core combining generator excitation control and protection functions, designed to work in tandem with REG/REL670 generator protection devices. Classified under the AC800PEC power-specific control platform, it serves as the central hub for excitation regulation, fault protection and signal acquisition of thermal, hydro and gas-fired synchronous generators ranging from 10MW to 1000MW. The PCD235B101 is a hardware upgraded variant of PCD235A101 with full compatibility in mounting layout, pin definition and programming.
(Photos: PCD235B101 Physical Photo 1; PCD235B101 Physical Photo 2; Overall Appearance)
1. Basic Model Information
- Model: PCD235B101
- ABB Original Part Code: 3BHE032025R0101
- Product Series: Unitrol Excitation Control System, AC800M/System800xA DCS Power Edition (AC800PEC)
- Application: AVR automatic voltage regulation, rotor protection, de-excitation logic, unit interlock control for turbine, hydro and gas generators, as well as auxiliary calculation for generator stator fault protection.
2. Core Hardware Specifications
2.1 Processor & Memory
- CPU: Industrial enhanced PowerPC real-time processor with dedicated real-time arithmetic architecture for excitation control
- Operational RAM: 32MB; Non-volatile Flash Memory: 16MB (data retention upon power failure)
- Control Cycle: Minimum task scan cycle = 10ms, fulfilling millisecond-level rapid voltage adjustment and high-speed fault protection for excitation systems.
2.2 Power Supply Ratings
- Rated Input: 24VDC (wide input range: 18~30VDC), dual redundant power supply supported
- Total Power Consumption: ≤25W; dual-power feeding via cabinet backplane or external 24VDC source.
2.3 Onboard I/O Terminal Configuration
表格
| Interface Type | Specification | Application |
|---|---|---|
| DI Digital Input | 12 channels, 24/48VDC | Position feedback of field breaker, cooling fan status, fast fuse fault, unit start/stop status signals |
| DO Relay Output | 16 channels, dry contact rated at AC250V/5A | Field breaker closing/tripping, fan start-stop, fault trip, protection trip output |
| AI Analog Input | 3 channels, ±10V / 4~20mA, acquisition accuracy ±0.1% FS | Generator terminal voltage, rotor excitation voltage, rotor current, winding temperature measurement |
| AO Analog Output | 2 channels, 0~10V | Excitation reference regulation, remote reactive power analog output |
2.4 Communication Interfaces
- Dual-channel 10/100Mbps auto-adaptive industrial RJ45 Ethernet, supporting Modbus TCP, IEC60870-5-104 and proprietary Unitrol protocol
- Dual isolated RS485 ports for Profibus-DP and Modbus RTU, used for connection with supervisory DCS and REG670 protection relays
- Reserved slot for optional fiber optic communication module to resist severe electromagnetic interference in power plants.
2.5 Mechanical Dimension & Environmental Parameters
- Overall Dimension: 381×152×76mm (standard rack mounting for control cabinet)
- Weight: Approx. 1.5kg
- Ingress Protection: IP20 (for indoor cabinet installation only)
- Operating Temperature: -25℃ ~ +70℃ (wide industrial range); Storage Temperature: -40℃ ~ +85℃
- Relative Humidity: 5%~95% RH non-condensing; vibration resistance compliant with IEC60068-2-6 power plant standard.
3. Functional Description (Excitation & Generator Protection)
3.1 Excitation Control (Core AVR Functions)
Automatic Voltage Regulator (AVR) supports three regulation modes: constant terminal voltage, constant reactive power and constant power factor.
Built-in protection limiters include under-excitation/over-excitation limitation, V/F limitation and stator current limitation, plus soft field build-up and soft de-excitation logics.
Adopts 1:1 dual-channel hardware redundancy; bumpless master-slave switchover within <200ms to realize hot standby without generator shutdown.
3.2 Embedded Generator Protection Logic (cooperates with external protection relays for full-set unit protection)
- Rotor-side Protection: Loss-of-excitation protection (ANSI 40), rotor overcurrent protection (ANSI 51V), excitation winding overvoltage protection and rotor earth fault protection
- Interlock Protection: Excitation blocking upon fan failure or rectifier fast fuse blowout; de-excitation trip triggered by accidental forced field
- Protection setting values, action logics and trip output logics can be customized via PCM600 configuration software.
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