FWL Series Generator Microcomputer Excitation System

The excitation system is an important part of the generator control system, which is used to regulate the terminal voltage and reactive power of the generator and thus to improve the stability limit and transmittability of the power grid. The excitation system consists of excitation power supply and excitation device. The main body of the excitation power supply is the exciter or excitation transformer; the excitation device consists of regulator, rectification, de-excitation and energization.

NARI initiated its excitation industry in 1985. At present, it has developed the first microcomputer excitation regulator over the world and also put it into industrial operation. As the leading enterprise in China’s generator excitation industry, NARI is the only one manufacturer in China that can provide 1,000MW turbine generators, 700MW hydro turbine generators, 300MW pumped storage generator units and heavy-duty gas turbine generator excitation systems that have completely independent intellectual property rights. All the above patents have won the First Prize of China Electric Power Science and Technology Progress Award and the Third Prize of National Science and Technology Progress Award. The accreditation board held by Chinese Society of Electrical Engineering identified the main indexes of the system developed by NARI have obtained the international advanced level, in which the primary-auxiliary ring coordination control and special de-excitation techniques have been ranking topmost over the world.


The excitation products of NARI have been widely applied in thermal power, hydropower, gas turbine and pumped energy storage fields as well as in many overseas markets, such as Saudi Arabia, Turkey, India, Indonesia, Chile and Peru.

Maintain the voltage of the generator or other control points at the given level; assure the safety of operating units in the electric power systems and the economy of the generation operation;


Control and properly distribute the reactive power of parallel operating unit;


Improve the stability of the electric power system and the transmission limit of electric energy;


Meet the informatization demand on excitation system of the smart substation.

Pass CE and TUV certifications;


Comply with GB7409, DL650 and IEEE421;


The control operation cycle is only 1.666ms, which makes the excitation control and limit protection model accurate;


Standard PID control mode: serial correction or parallel correction can be selected as actually required;


Optional PSS2B/PSS4B electric power system stabilizer model: effectively inhibit the low-frequency oscillation of the power grid;


Complete control, limit and protection functions to achieve the coordinated control among all sections and the unification between rapidness and stability;


Redundant fault tolerance function: Improve the capability of the system to maintain the units in working order in case they are in anomalies or the components are in anomalies, and hence complete the fault tolerance control and anti-mis-operation of the excitation system;


Support MODBUS, IEC60870-5-103 and IEC61850 communication protocols; meet the demands of smart substation;


Complete fault recording function and files in COMTRADE format under IEEE standards for facilitating the analysis;


Advanced automatic monitoring platform operating on special Linux system, highly safe and reliable.

Resolution of thyristor control angle α: 0.0072


A/D conversion quantity resolution: 16-bit sampling


Sampling mode: Direct AC sampling, with 36 points sampled per cycle


Control operation regulating cycle: 1.666ms


Voltage regulation range: 5% - 130%


Accuracy of voltage regulation: <0.1%


Phase shifting range 0~180°, with upper limit and lower limit settable by program


Difference adjustment: reactive different adjustment rate set by software, freely optional for plus-minus characteristic and values; grade difference: ±0.1%


Frequency characteristic: once the frequency of generator alters by 1% every time, the change of generator terminal voltage is not more than ±0.1% of the rated value


Increase/decrease regulation speed: configurable, 0.3% – 1% (including both end values) per second


Voltage response time: rise <0.08s, fall <0.15s


Frequency response range: 5-500Hz

This system can be applied in various types of generator units, such as nuclear power generator unit, thermal power generator unit, conventional hydro turbine generator unit, pumped storage generator unit and gas turbine generator unit.

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