ABB REG216 Digital Generator Protection System

Comprehensive Analysis of ABB REG216 Digital Generator Protection System

With the continuous expansion of power system scale and the improvement of intelligence level, higher requirements have been put forward for the reliability, accuracy, and flexibility of generator and main transformer protection devices. ABB's REG216 and its classic version REG216 Classic, as fully digital generator and main transformer protection systems, have become important solutions in the field of modern power protection due to their modular hardware design, optional protection function library, fully digital signal processing, and powerful self checking and communication capabilities. This article will provide an in-depth analysis of the system from multiple dimensions, including system architecture, protection functions, technical parameters, and configuration options.

System Overview and Core Features

The REG216 system is designed specifically for the protection of generators and main transformers. Its hardware adopts a modular structure, and its software integrates a rich protection function library. Users can flexibly choose and configure protection schemes according to their actual needs. The system has the following core features:

Full digital signal processing: using a sampling rate of 12 times the rated frequency (600Hz for 50Hz systems and 720Hz for 60Hz systems), with a dynamic range of up to 15 bits, achieving high-precision and high stability signal acquisition and processing.

Modular hardware design: The system consists of two main parts: an interface unit (such as input transformer component 216GW62, auxiliary relay components 216GD61a/216GE61/216GA61/216GA62) and an electronic processing unit (such as processor 216VC624, analog input unit 216EA62), which are connected through shielded cables for easy expansion and maintenance.

Software configurable protection function: Provides a complete function library covering generator, transformer, and feeder protection. Users do not need programming knowledge and can activate and configure protection functions through PC tools (such as CAP2/316) in a "drag and drop" manner.

Continuous self checking and monitoring: Hardware has the ability to perform continuous self checking, while software performs periodic testing, greatly reducing the need for traditional periodic injection testing and improving system availability.

Flexible communication and integration: Supports multiple communication protocols such as RS232, LON bus, MVB process bus (compliant with IEC 61375), and can seamlessly integrate with station control systems to achieve data upload and remote control.

Detailed explanation of main protection functions

REG216 integrates dozens of standard protection functions, and the following are some key functions and their technical features:

1. Generator differential protection (87G)

Adopting three-phase current adaptive characteristics, it has high stability and can effectively resist external faults and CT saturation effects. The action time shall not exceed 30ms when the current is greater than twice the rated value, with a sensitivity setting range of 0.1~0.5In and a step size of 0.05In.

2. Transformer differential protection (87T)

Suitable for two winding or three winding transformers, with built-in vector group and CT ratio compensation, without the need for auxiliary transformers. Provide second harmonic braking function to prevent excitation inrush current misoperation, with an action time not exceeding 30ms (>2In) under full load conditions.

3. Fixed time and inverse time overcurrent protection (51/51DT/67)

Provide overcurrent and undercurrent detection for phase and ground faults, supporting timed and multiple inverse time characteristics (such as normal inverse time, abnormal inverse time, and extreme inverse time). Directional overcurrent protection (67) has voltage memory function and is suitable for near end faults.

4. Grounding protection for stator and rotor (64S/64R)

100% stator grounding protection is based on the principle of voltage displacement, which can monitor the insulation status of the entire stator winding, covering both static and operating conditions. It needs to be used in conjunction with the REX010 injection unit and REX011 transformer module. The rotor grounding protection also provides continuous insulation monitoring, and the alarm and trip thresholds can be set between 100 Ω and 25k Ω.

5. demagnetization protection (40) and step loss protection (78)

The minimum reactance protection (40) is used to detect synchronous motor demagnetization faults, with circular characteristics, and can be set to trip within or outside the zone. The out of step protection (78) can detect sliding pole frequencies of 0.2-8Hz, identify the oscillation center position through impedance trajectory, and achieve two-stage tripping.

6. Voltage, frequency, and power protection

The system provides overvoltage/undervoltage (59/27), overvoltage/underfrequency (81), frequency change rate (df/dt), overexcitation (24), and power protection (32, including active, reactive, reverse power, etc.). All functions can be set for single-phase or three-phase measurement and have a voltage lockout mechanism.