CN105591503A

CN105591503A - Multi-pair excitation slip rings

Info

Publication number: CN105591503A
Application number: CN201410554383.7A
Authority: CN
Inventors: 何长平
Original assignee: China Yangtze Power Co Ltd
Current assignee: China Yangtze Power Co Ltd
Priority date: 2014-10-20
Filing date: 2014-10-20
Publication date: 2016-05-18

Abstract

The invention provides multi-pair excitation slip rings comprising at least two pairs of slip rings. Each slip ring comprises a slip ring positive electrode and a slip ring negative electrode. Each slip ring is provided with multiple carbon brushes. The slip ring positive electrode and the slip ring negative electrode are connected with two ends of a rotor. The multiple carbon brushes on one slip ring are mutually connected. The multiple carbon brushes arranged on one slip ring of the pairs of the slip rings are connected with the positive electrode of the rotor, and the multiple carbon brushes arranged on the other slip ring of the pairs of the slip rings are connected with the negative electrode of the rotor. According to the multi-pair excitation slip rings, the number of the slip rings is increased and the requirement for set space is low; current flowing through a single carbon brush is reduced so that the service life of the carbon brush is prolonged; and the number of the carbon brushes is increased so that higher rotor current can be borne, and thus the multi-pair excitation slip rings can be applied to large-scale power generator sets and high-rotating-speed power generator sets.

Description

A kind of multipair excitation slip ring

Technical field

The present invention relates to a kind of large synchronous generator parts, particularly a kind of multipair excitation slip ring.

Background technology

Large synchronous generator is all by producing magnetic field to the logical direct current of Exciting Windings for Transverse Differential Protection to complete the conversion of mechanical energy-electric energy. The simplest excitation mode is exactly the generator amature of by slip ring, exciting current being sent into rotation now, and all energizing apparatus all remain static, therefore be called static excitation. For rotating excitation, structure is simpler, cost is low, reliability is high, it is safer to move, control accuracy is high for static excitation system, workable. On excitation mode, big-and-middle-sized unit adopts from shunt excitation static excitation mode more. It is fast that this excitation mode has reaction speed, and dynamic quality is good, can improve the speciality such as the transient stability of unit and power system. But static excitation system has been brush excitation, all adopt 1 to (each one group of positive and negative electrode slip ring) slip ring, exciting current to be passed into rotor winding, with respect to brushless excitation generator, there is brush excitation tool in the technical characteristics such as dynamic stability, troubleshooting, de-excitation time-constant and function debugging to have great advantage. But carbon brush and slip ring serious wear, grade of spark exceed standard, and even cause ring fire, it is the key factor that impact has brush excitation generator operating condition always. Along with unit capacity is increasing, the required exciting current providing of excitation system is also increasing, and the continuous firing ability that the conductive capability of a pair of slip ring and carbon brush, temperature resistance rise (especially steam turbine generator) under ability and high rotating speed operating mode is difficult to meet the requirements at the higher level of the above unit of 100MW.

Existing static excitation system both positive and negative polarity is two slip rings (1 pair) only, and carbon brush is evenly distributed on both positive and negative polarity slip ring, as shown in the accompanying drawing 1 in Figure of description. Under large load, high power capacity, high-revolving operating mode, carbon brush and slip ring very easily generate heat, wears and tears, cause that contact resistance is unstable, carbon brush sparking, even affect the idle fan-out capability of generator seriously time.

Summary of the invention

For solving the problems of the technologies described above, the invention provides a kind of multipair excitation slip ring, increase slip ring quantity, not high to unit space requirement; Reduce single carbon brush by electric current, extend carbon brush service life; Increase carbon brush quantity, can carry larger rotor current, this multipair excitation slip ring can be applicable to Generator Set, high tacho generator group.

The technical scheme that the present invention takes is:

A kind of multipair excitation slip ring, comprises at least two pairs of slip rings, and each slip ring includes slip ring positive pole, slip ring negative pole, and each slip ring is provided with multiple carbon brush. Described slip ring positive pole, slip ring negative pole connect the two ends of rotor.

Between multiple carbon brush on a described slip ring, interconnect. The multiple carbon brush that are positioned on a slip ring on paired slip ring connect rotor positive pole, and the multiple carbon brush that are positioned on another slip ring on paired slip ring connect rotor negative pole.

Described slip ring is four, totally two pairs.

A kind of multipair excitation slip ring of the present invention, organizes slip ring power supply more, increases rotor current handling capacity; Many carbon brush interconnect, and improve power supply reliability. Reduce carbon brush abrasion, temperature rise, sparking, increase the service life.

Brief description of the drawings

Fig. 1 is two slip ring structure schematic diagrames of existing static excitation system both positive and negative polarity described in background technology.

Fig. 2 is a kind of multipair excitation slip ring structure schematic diagram of the present invention.

Wherein, the dotted line in Fig. 1, Fig. 2 represents large shaft centre line.

Detailed description of the invention

As shown in Figure 2, a kind of multipair excitation slip ring, comprises at least two pairs of slip rings 1, and each slip ring 1 includes slip ring positive pole 1.1, slip ring negative pole 1.2, and each slip ring 1 is provided with multiple carbon brush 2. Described slip ring positive pole 1.1, slip ring negative pole 1.2 connect the two ends of rotor 3. Between multiple carbon brush 2 on a described slip ring, interconnect.

The multiple carbon brush 2 that are positioned on a slip ring on paired slip ring connect rotor positive pole 4.1; The multiple carbon brush 2 that are positioned on another slip ring on paired slip ring connect rotor negative pole 4.2.

Described slip ring 1 is four, totally two pairs. Suppose that carbon brush quantity is that carbon brush quantity on the single slip ring of 2N(is N), the contact resistance of single carbon brush and slip ring is R_j, as exciting current I_fWhen constant, the electric current of flowing through of single carbon brush is I_f/ N, the contact loss power P causing₁=(I_f/N)2*R_j; If be still N by slip ring 1 quantity from the 2 carbon brush quantity that are adjusted into the each slip ring of 4(), the electric current of flowing through of single carbon brush is I_f/ 2N, the contact loss power causing is P₂=(I_f/2N)2*R_j=0.25P₁. As can be seen here, increase slip ring quantity, and then increase carbon brush quantity. Can make the electric current of flowing through of single carbon brush be reduced to 1/2nd, contact loss power reduction is 1/4th, can significantly reduce carbon brush temperature rise, effectively reduce carbon brush sparking and heating, security while changing carbon brush is higher, the reliability that four slip rings 1 are powered is also higher, the I that corresponding large capacity unit can carry_fAlso larger.

Claims

1. a multipair excitation slip ring, it is characterized in that, comprise at least two pairs of slip rings (1), each slip ring (1) includes slip ring positive pole (1.1), slip ring negative pole (1.2), and each slip ring (1) is provided with multiple carbon brush (2); Described slip ring positive pole (1.1), slip ring negative pole (1.2) connect the two ends of rotor (3); Between multiple carbon brush on a described slip ring, interconnect; The multiple carbon brush that are positioned on a slip ring on paired slip ring connect rotor positive pole (4.1), and the multiple carbon brush that are positioned on another slip ring on paired slip ring connect rotor negative pole (4.2).

2. a kind of multipair excitation slip ring according to claim 1, is characterized in that, described slip ring (1) is four, totally two pairs.