The Research And Manufacture Of Double-channel Microprocessor-based Excitation Regulators

Excitation system is an important part of power system. It has important effectto regulate the voltage of synchronous generator, distribute reactive power andimprove the stabilization of power system. Excitation system is made up of regulatorand power units. The regulator, as the core of excitation system, carries out its basiccontrol functions, excitation limits and other assistant functions.As a single synchronous generator's electric power becomes higher and thescale of power system becomes bigger, synchronous generator and power system hasmore demand on expeditiousness, reliability and multi function of excitation system.Modern excitation regulator is called microprocessor-based regulator because itis used microprocessor as its central control unit. Its' basic control functions,excitation limits and other assistant functions are carried out by software programswhich are run in microprocessor. Microprocessor-based excitor has rapid regulatingspeed, high precision, more reliability and other excellences.What Double-channel microprocessor-based excitation regulators mean that onesynchronous generator has two microprocessor-based regulators, one as the main, theother as the backup. It can improve reliability of excitation system.This research program is supported by Nanjing Nari Automation institute.Three-phasic controllable commutating circuit, which is made up of SiliconControlled Rectifier (SCR), is used in excitation system as power unit. The controlport of SCR is controlled by the microprocessor-based regulator. This paper usesDSP as the main control chip of the microprocessor-based regulator and CPLD as itsinterface circuits, designs process circuits of analog signals, logical signals andpulse-open circuit. This paper also uses ameliorated PID arithmetic to carry outregulator's basic control functions, excitation limits and other assistant functions bysoftware programs. In order to harmonize double microprocessor-based regulators'working, ensure only one regulator's output in effect and switch between tworegulators without disturbing outputs, the paper designs communication circuits andpulse closedown and control circuits between them.Experiments show that the microprocessor-based excitation regulators meetindustry standards in regulating speed, precision, reliability and stability both on thecondition of generator's open circuit and in load.