A load shedding control method and system

Abstract

The present application belongs to the technical field of gas turbine design, and relates to a load rejection control method and system. The method includes first, after detecting a generator trip signal, obtaining the generator stator current and the gas generator conversion speed; The limit value judges whether to enable the load rejection transient process control, and the load rejection transient process control includes: taking the fuel quantity corresponding to the idle speed as the target fuel adjustment amount in the rotor down-rotation process of the load rejection transient process, according to the pre- The determined minimum oil-gas ratio limit curve controls the fuel change during the adjustment process; and when the down speed of the power turbine is less than the set value, the load rejection transient process control is jumped out. In this application, by introducing trip signal and current signal, and adjusting the flow area of ​​the power turbine guide, it is possible to timely and accurately determine that the gas turbine has load shedding, which is beneficial to delay the performance degradation of the gas turbine. At the same time, the adjustable technology of the flow area of ​​the power turbine guide is adopted. .

Description

technical field [0001] The application belongs to the technical field of gas turbine design, and in particular relates to a load rejection control method and system. Background technique [0002] When gas turbines are used in isolated grid power generation in the field of emergency backup power and ship electric propulsion, they will inevitably face the problem of circuit breaker tripping caused by problems such as generator and load failure, overload, that is, load shedding, and the output shaft of the power turbine will lose all power instantly Load, while its output power is basically unchanged, the huge power imbalance on both sides of the shafting will cause it to bear a large acceleration. If the control is not timely, it will cause over-rotation protection to stop or the rotor will fly. [0003] Generally, industry standards require that gas turbines should have the ability to shed load without stopping under 100% rated operating conditions, and the overshoot of the p...

AI Technical Summary

Problems solved by technology

[0008] 1) The conventional gas generator and power turbine speed cascade closed-loop adjustment scheme can maintain the steady-state power generation frequency at 50 Hz, and its stability adjustment quality for linear or approximately linear load changes is good, but for strong nonlinear, changing speed The suppression effect of fast isolated grid power generation load disturbance is average, and the adjustment followability is poor

[0009] 2) The speed acceleration of the power turbine can reflect the change of the load, but it is difficult to distinguish whether it is a normal sudden drop, a load shedding under low working conditions, or a load shedding under high working conditions, and there is a certain time delay, which leads to control The response time of the system is long

[0011] ① It is necessary to extend the transition section of the turbine casing, increase the design of the bleed valve and bleed pipeline, etc., resulting in an extension of the axial size and weight of the gas turbine

[0012] ②The selection of deflation according to the increase in the speed of the power turbine cannot quickly suppress the increase in the initial acceleration

[0013] ③Due to the high temperature at the inlet of the power turbine, venting here not only has special requirements for the vent valve and pipeline materials, but also has potential safety hazards of high-temperature gas leakage

[0014] 4) The technical scheme of increasing the moment of inertia of the power turbine, reducer and generator shafting needs to redesign the shafting structure of the power system, which will not only increase the cost, but also increase the mass and size of the unit

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