A kind of hydraulic turbine AC excitation power source protection method and realize the hydraulic turbine of this method
Technical field
The present invention relates to a kind of hydraulic generator, particularly a kind of AC excitation hydraulic turbine.
Background technology
Development along with hydraulic turbine technology, hydraulic turbine variable frequency excitation technology comes into one's own day by day, the variable frequency excitation technology has overcome the shortcoming of traditional DC excitation technology, can allow the hydraulic turbine generate electricity in wideer working range, can significantly improve the economic benefit in hydroelectric station.But the needed frequency converter field power supply of variable frequency excitation technology is the comparison fragility, and its overload capacity is poor; This factor affecting is little under normal operation; but the hydraulic turbine can damage the variable frequency excitation power supply at high pressure and the big electric current that rotor-side produced when electrical network breaks down, and therefore presses for the safety that a kind of protective circuit of design guarantees hydraulic turbine frequency converter field power supply when electrical network breaks down.
Summary of the invention
The purpose of this invention is to provide a kind of AC excitation power source protection method and realize the hydraulic turbine of this method, in order to solve that hydraulic turbine ac excitation power supply is subject to fault effects and the problem damaged.
For achieving the above object, a kind of scheme of the present invention is: a kind of hydraulic turbine AC excitation power source protection method, and step is as follows:
A) detect hydroturbine rotor side electric current, and set a current reference value;
B) when detected electric current surpasses described reference value, block the output of ac excitation power supply, simultaneously by switching device with a protective circuit input;
C) continue detection rotor side electric current, when detected electric current was lower than reference value, output and the control switch device of opening ac excitation power supply excised protective circuit.
Adopt above-mentioned AC excitation power source protection method, can under electric network fault or the big current conditions of rotor-side, utilize protective circuit to absorb fault current and clamper rotor-side voltage, thus the protection ac excitation power supply.
Among described step b, the c, described protective circuit is in parallel with excitation winding, is used for the control protection electric circuit input and the switching device that cuts out is serially connected in protective circuit.Be provided with the protective resistance that is used to absorb big electric current in the described protective circuit.
For achieving the above object; another kind of scheme of the present invention is: a kind of hydraulic turbine of realizing the AC excitation power source protection method; comprise ac excitation power supply and excitation winding; a protective circuit is set on the circuit between ac excitation power supply and the excitation winding; protective circuit is in parallel with excitation winding; string is provided with switching device that is used for the control circuit break-make and the high-power resistance that is used to absorb exciting current in the protective circuit; a sampling module is arranged in the energized circuit; its output connects the input of a control module, and two outputs of control module are corresponding switching device and ac excitation power supply respectively.
Adopt the hydraulic turbine of above-mentioned AC excitation power source protection method, can under electric network fault or the big current conditions of rotor-side, utilize protective circuit to absorb fault current and clamper rotor-side voltage, thus the protection ac excitation power supply.
Described protective circuit comprises a rectifier, and input is connected on the output bus of ac excitation power supply, and two of the series circuit that described high-power resistance and described switching device constitute terminates on the output of rectifier.Described rectifier is the three-phase bridge rectifier that is made of six diodes.Described switching device is IGBT or thyristor.
Description of drawings
Fig. 1 is a hydraulic turbine protective circuit schematic diagram.
Embodiment
A kind of hydraulic turbine AC excitation power source protection method of the specific embodiment of the invention, step is as follows:
A) detect hydroturbine rotor side electric current, and set a current reference value;
B) when detected electric current surpasses described reference value, block the output of ac excitation power supply, simultaneously by switching device with a protective circuit input;
C) continue detection rotor side electric current, when detected electric current was lower than reference value, output and the control switch device of opening ac excitation power supply excised protective circuit.
A kind of hydraulic turbine B that realizes the AC excitation power source protection method; rotor side joint excitation winding; stator outputs to electrical network C; as shown in Figure 1; comprise ac excitation power supply A and excitation winding; a protective circuit in parallel with excitation winding is set between ac excitation power supply A and excitation winding; protective circuit comprises a rectifier D; input is connected on the output bus of ac excitation power supply A; two of the series circuit that is made of high-power protective resistance E and IGBT switch module F terminates on the output of rectifier D, and switch module F also can adopt thyristor.Rectifier D is the three-phase bridge rectifier that is made of six diodes.In addition, a sampling module G is set in energized circuit also, the rotor-side excitation winding electric current that is used for sampling, its output connects the input of a control module H, and this control module H has two outputs, respectively corresponding control switch device F and ac excitation power supply A.The output of control module H can connect the control end of IGBT; thereby it is the rotor-side current feedback that samples is defeated to the control of IGBT; can set a current reference value by control module H, when sampling hydroturbine rotor side electric current above reference value, the IGBT conducting; protective resistance E is put in the circuit; thereby sponge the big electric current and the clamper rotor-side voltage of rotor-side, be lower than reference value when sampling electric current, promptly electric current recovers normal; then IGBT turn-offs, and protective resistance E cuts out circuit.