CN204361666U - Motor self-balancing differential protection structure - Google Patents
Motor self-balancing differential protection structure Download PDFInfo
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- CN204361666U CN204361666U CN201420642787.7U CN201420642787U CN204361666U CN 204361666 U CN204361666 U CN 204361666U CN 201420642787 U CN201420642787 U CN 201420642787U CN 204361666 U CN204361666 U CN 204361666U
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- motor
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- differential protection
- balancing
- current transformer
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Abstract
The utility model motor self-balancing differential protection structure, its high-tension switch cabinet comprising motor and be connected with motor, in motor three-phase windings the head of every phase, tail 2 lead-out wires by polarity simultaneously through 1 self-balancing current transformer.The utility model greatly can reduce the possibility of protective device malfunction; the sensitivity of protection greatly can be improved compared with other is protected; therefore can run for the long-term stability of unit, shorten the time between overhauls(TBO) and create conditions, also can increase energy output, for power plant creates more benefit simultaneously.
Description
Technical field
The utility model technology is applied to thermal power plant high pressure 2000kW and above motor, if desired, also can be used for the motor being less than 2000kW.
Background technology
At present, what power plant 2000kW and the differential protection with upper motor generally adopted is install one group of current transformer in switch cubicle, and motor neutral point installs the differential protection that one group of current transformer forms motor.The existing technical regulation of this Main Basis China power industry, Specification Design.
As described in Figure 1, it is existing conventional electric motor differential protection structure.Its high-tension switch cabinet 2 comprising motor 1 and be connected with motor 1; motor is arranged in motor main junction box 11; motor neutral point connects the differential protection that three the first current transformers 31 are formed; differential protection also comprises the 3rd current transformer 33 of three measuring second current transformers 32 and three differential protections and other protections, and this second current transformer and the 3rd current transformer are placed in switch cubicle.
The shortcoming of this mode is:
1. owing to bearing different for the first current transformer of differential protection and the actual secondary of the second current transformer; therefore; the electric current difference that (such as during motor starting) is respective exported when larger current is comparatively large, easily causes Miss-operation of Motor Differential Protection.Common solution improves the operating value of protection, or increase the criterion of through current.The former causes the sensitivity decrease protected usually, and latter causes the logic of protection complicated, and the operate time of protection is extended.
2. the different shaped of two kinds of current transformers.This also causes the electric current difference sending into protection to increase, and solution is only improved the operating value of protection.
Utility model content
In view of this; the technical problem that the utility model solves is to provide a kind of motor self-balancing differential protection structure; greatly can reduce the possibility of protective device malfunction; and greatly the sensitivity protected can be improved compared with existing operator guards; for ensureing that the long-term stability of unit is run, the shortening time between overhauls(TBO) creates conditions; thus increase energy output, create benefit.
The utility model patent adopts following technical scheme: motor self-balancing differential protection structure; its high-tension switch cabinet comprising motor and be connected with motor; it is characterized in that: in motor three-phase windings the head of every phase, tail 2 lead-out wires by polarity simultaneously through 1 self-balancing current transformer; install three-phase type motor protecting device in switch cubicle, it comprises the second current transformer and the 3rd current transformer.
The utility model technology adopts the advantage of technique scheme to be: the possibility that greatly can reduce protective device malfunction; the sensitivity of protection greatly can be improved compared with other is protected; therefore can run for the long-term stability of unit, shorten the time between overhauls(TBO) and create conditions; also energy output can be increased, for power plant creates more benefit simultaneously.
Accompanying drawing explanation
Fig. 1 is existing conventional electric motor differential protection structural representation.
Fig. 2 is structural representation of the present utility model.
Embodiment
As shown in Figure 2; the utility model motor self-balancing differential protection structure; its high-tension switch cabinet 2 comprising motor 1 and be connected with motor 1; motor is arranged in motor main junction box 11; its emphasis in: in motor 1 three-phase windings 11, the head of every phase, tail 2 lead-out wires are by polarity simultaneously through 1 self-balancing current transformer 3 (being also magnetic balance current transformer), and the secondary side of self-balancing current transformer succeeds electrical protective device.In addition; same installation three-phase type motor protecting device in switch cubicle 2; it is the simplest current quick of one; and do not need time delay; it is a set of common motor protection conventionally configured; it can comprise measuring second current transformer 32, and other protection the 3rd current transformers 33 except differential protection.
This programme has the following advantages:
1. be designed to power frequency operation, when changing converting operation into, operator guards of the present utility model is without the need to change.This is because when normally running, the characteristic that the electric current of inflow motor has all the time with the electric current flowing out motor " equal and opposite in direction, direction contrary ", no matter and the electric current of inflow motor is power frequency or frequency conversion.
2. the self-balancing differential protection of the utility model motor both can adjust (now the sensitivity of protective device is the highest) according to minimum fault current; also can adjust according to coordinating with the fast tripping protection at power supply place, to ensure not having dead band when big current short circuit.
For China in recent years unit capacity constantly increase, make full use of the design feature of motor self-balancing differential protection, improve protection sensitivity; reduce the dead band of protection; improve protection act speed, thus shorten the repair time, for country and enterprise create better, more service conditions.
Be below case history: the power plant 600MW turbo generator set of design, its primary air fan by 4300kW motor driven, the motor self-balancing differential protection structure of this case of employing.When starting 2A primary air fan, 2A primary air fan switch trip, the action of protective device display zero-sequencedirectional protection, and the action of self-balancing differential protection.Self-balancing differential protection setting value is 0.1A, and time delay 0s action is in tripping operation.After protection act; respectively survey insulation is carried out to high-tension cable and motor winding; cable insulation is good, and motor winding three-phase over the ground resistance is respectively: A:1G Ω, B:1G Ω; C:0.2M Ω; open the end cap inspection of motor both sides, find fault point 3 place at shaft coupling side stator end, be stator core notch front rod scaling loss; confirm as motor fault, protect correct operation and excised fault fast.Due to the quick acting of protective device, reduce the difficulty of reparation, reduce loss.
Claims (1)
1. motor self-balancing differential protection structure; its high-tension switch cabinet comprising motor and be connected with motor; it is characterized in that: in motor three-phase windings the head of every phase, tail 2 lead-out wires by polarity simultaneously through 1 self-balancing current transformer; install three-phase type motor protecting device in switch cubicle, it comprises the second current transformer and the 3rd current transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420642787.7U CN204361666U (en) | 2014-10-31 | 2014-10-31 | Motor self-balancing differential protection structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420642787.7U CN204361666U (en) | 2014-10-31 | 2014-10-31 | Motor self-balancing differential protection structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204361666U true CN204361666U (en) | 2015-05-27 |
Family
ID=53263113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420642787.7U Active CN204361666U (en) | 2014-10-31 | 2014-10-31 | Motor self-balancing differential protection structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204361666U (en) |
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2014
- 2014-10-31 CN CN201420642787.7U patent/CN204361666U/en active Active
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: CHINA POWER ENGINEERING CONSULTING GROUP NORTH CHI Free format text: FORMER NAME: NORTH CHINA ELECTRIC POWER DESIGN INSTITUTE OF CHINA POWER ENGINEERING CONSULTING GROUP CORPORATION |
|
| CP01 | Change in the name or title of a patent holder |
Address after: 100120 Beijing city Xicheng District Street No. 24 Patentee after: NORTH CHINA POWER ENGINEERING CO., LTD. OF CHINA POWER ENGINEERING CONSULTING GROUP Address before: 100120 Beijing city Xicheng District Street No. 24 Patentee before: North China Electric Power Design Institute of China Power Engineering Consulting Group Corporation |