CN204615376U - 500kV and above high voltage transformer neutral point current limiting device over the ground - Google Patents
500kV and above high voltage transformer neutral point current limiting device over the ground Download PDFInfo
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- CN204615376U CN204615376U CN201520329149.4U CN201520329149U CN204615376U CN 204615376 U CN204615376 U CN 204615376U CN 201520329149 U CN201520329149 U CN 201520329149U CN 204615376 U CN204615376 U CN 204615376U
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Abstract
The utility model relates to 500kV and above high voltage transformer neutral point current limiting device over the ground, one high voltage power network transformer neutral point is provided, described high voltage transformer neutral point is provided with small-sized air-core reactor, injects the high-frequency resonance current of ground network in order to be decreased through neutral point.Propose in the utility model to set up small-sized air-core reactor, high-frequency resonance and the electromagenetic wave radiation problem of electrical network is alleviated by less investment, reduce high-frequency resonance current simultaneously, effectively can reduce the heating loss of transformer, improve transformer operational reliability and useful life.
Description
Technical field
The utility model belongs to power domain, is specifically related to a kind of 500kV and above high voltage transformer neutral point current limiting device over the ground.
Background technology
The transformer neutral point of early stage domestic electrical system 110kV and above all adopts direct ground connection.From 2005, in order to reduce switchgear cost, reduce short circuit current, the transformer neutral point that relevant expert proposes 500kV system with leader can adopt through iron core low reactance earthing mode; The transformer neutral point of 110kV and 220kV system, after checking checking computations, can adopt not direct grounding way during operation; But transformer neutral point overvoltage protection (i.e. discharging gap) must be set up.At present, the some transformers neutral point series connection iron core oil-immersed type small reactor ground connection of 500kV system in electrical network, the direct ground connection of all the other 500kV transformer neutral points.
In " extra-high voltage grid ", listed the electromagnetic field density distributed data in 500kV transformer station, the density of CURRENT DISTRIBUTION over the ground that charging equipment and circuit generate an electromagnetic field reaches 3A ~ 10A/m2, has seriously exceeded the health tolerance of occupational staff.Main cause is that the major loop of a large amount of electric equipment all exists earth point and constitutes straightway current channel over the ground, and transformer neutral point ground connection is maximum current channel over the ground.All there is very large impedance in A, B, C tri-phase iron core coil self that neutral point connects outwardly, and reactance value is wherein directly proportional to frequency; Seem to have the ability of good stop high-frequency current, high-frequency resonance can not occur.But the turn-to-turn distance in fact in each phase coil is less, there is capacity effect between adjacent coiling; If frequency raises, capacitor value significantly declines, and can form high-frequency current passage.Also have the magnetic permeability of transformer core material raise with frequency and significantly decline, under high frequency condition, reactance value is very little; Now coil is equivalent to heating resistor around the major loop of iron core, and high-frequency current still can pass through on a small quantity.In addition, the inductive relationship under normal condition between transformer primary winding and secondary coil still part exists, and also there is certain capacity effect in addition between coil and iron core or between iron and steel framework.But topmost high-frequency current passage is the earth point flowing into neutral point after each phase coil turn-to-turn penetrates forms loop.The signal frequency of the mobile communication 4G opened is at 1.8-2.5GHz, and communication signal is continuous frequency spectrum distribution in frequency range; And the microwave oven operating frequency that everyday home uses is 2.455 GHz, therefore in electrical network, the microwave oven effect of regional area is inevitable.Not only in transformer station there is very big hidden danger in the safe operation of electric equipment self, and the electromagnetic field running electric equipment generation is day by day serious to operation, the healthy suffered harm of maintainer.
The transformer neutral point of 500kV system adopts and effectively can reduce short circuit current through iron core low reactance ground connection, but it is not too obvious to the effect of earth-current to reduce high-frequency.Its reason is that the turn-to-turn distance in this series connection iron core oil-immersed type small reactor coil is less equally, there is capacity effect between adjacent coiling; And the magnetic permeability of iron core of electric reactor material raises with frequency and significantly declines, and does not almost have inductance value under 1MHz and above high frequency condition.Certainly, also there is certain capacity effect between coil and iron core or between iron and steel framework, but penetrate the loop formed with earth point between topmost high-frequency current passage or coil turn.Although the small reactor inductance effect under high-frequency condition is substantially lost, heating effect that is unshakable in one's determination and coil still exists; Its effect is equivalent to a small resistor capacitive reactances in parallel, can to a certain degree reduce high frequency to earth-current, just reduce numerical finite.
Summary of the invention
In view of this, the purpose of this utility model is to provide a kind of 500kV and above high voltage transformer neutral point current limiting device over the ground, reduce high-frequency resonance current simultaneously, effectively can reduce the heating loss of transformer, improve transformer operational reliability and useful life.
The utility model adopts following scheme to realize: 500kV and above high voltage transformer neutral point current limiting device over the ground, comprise a high voltage transformer neutral point, described high voltage transformer neutral point is provided with small-sized air-core reactor, injects the high-frequency resonance current of ground network in order to be decreased through neutral point.
Further, described high voltage transformer neutral point is provided with the iron core oil-immersed type iron-core reactor be in series with described small-sized air-core reactor.
Preferably, if described small-sized air-core reactor insulation level is lower than iron core oil-immersed type iron-core reactor, then connect with one end of described small-sized air-core reactor in one end of described iron core oil-immersed type iron-core reactor, and the other end of described small-sized air-core reactor is connected to earth point.
Preferably, if described small-sized air-core reactor insulation level is higher than iron core oil-immersed type iron-core reactor, then connect with one end of described iron core oil-immersed type iron-core reactor in one end of described small-sized air-core reactor, and the other end of described iron core oil-immersed type iron-core reactor is connected to earth point.
Further, described high voltage transformer neutral point is also provided with the resistor be in series with described small-sized air-core reactor; Connect with one end of described resistor in one end of described small-sized air-core reactor, the other end of described resistor is connected to earth point.The now effect of resistor is equivalent to the iron core reactor under high-frequency.
Preferably, in high-voltage fence, tens kHz and following low-frequency current are primarily of iron core reactor current limliting, and the electric current of 0.1MHz ~ 5GHz frequency range is primarily of little air-core reactor current limliting.Small reactor generally manufactures dry-type air-core reactor, but the insulating material of coil this should have buffer action to high-frequency current.The air-core reactor coil insulation majority run in present electrical network adopts insulating paper or chemical-fiber insulation material, and outdoor type is also wrapped up chemical-fiber insulation adhesive tape in addition and is coated with sun-proof paint; High-frequency current is caused to be penetrated by insulating material and paint, so small-sized air-core reactor manufacture must selected insulating material strict Controlling Technology.
Compared with prior art, the utility model increases small-sized air-core reactor in high-voltage fence, high-frequency resonance and the electromagenetic wave radiation problem of electrical network is alleviated with less investment, reduce high-frequency resonance current simultaneously, effectively can reduce the heating loss of transformer, improve transformer operational reliability and useful life, optimum facilitation is risen to the development of 500kV supergrid and 1000kV extra-high voltage grid from now on.
Accompanying drawing explanation
Fig. 1 sets up small-sized air-core reactor to suppress high-frequency current wiring schematic diagram in the utility model.
Fig. 2 sets up in the utility model before small-sized air-core reactor is connected on iron core reactor to suppress high-frequency current wiring schematic diagram.
Fig. 3 sets up small-sized air-core reactor and resistor suppression high-frequency current wiring schematic diagram in the utility model.
Label declaration: 1 is small-sized air-core reactor; 2 is iron core oil-immersed type iron-core reactor; 3 is resistor.
Embodiment
Below in conjunction with drawings and Examples, the utility model is described further.
The present embodiment provides 500kV and above high voltage transformer neutral point current limiting device over the ground, as shown in Figure 1, comprise a high voltage transformer neutral point, described high voltage transformer neutral point is provided with small-sized air-core reactor 1, injects the high-frequency resonance current of ground network in order to be decreased through neutral point.
In the present embodiment, described high voltage transformer neutral point is provided with the iron core oil-immersed type iron-core reactor 2 be in series with described small-sized air-core reactor 1.
In the present embodiment, preferably, if the exhausted 1 edge level of described small-sized air-core reactor is lower than iron core oil-immersed type iron-core reactor 2, then connect with one end of described small-sized air-core reactor 1 in one end of described iron core oil-immersed type iron-core reactor 2, and the other end of described small-sized air-core reactor 1 is connected to earth point.
In the present embodiment, preferably, as shown in Figure 2, if described small-sized air-core reactor 1 insulation level is higher than iron core oil-immersed type iron-core reactor 2, then connect with one end of described iron core oil-immersed type iron-core reactor 2 in one end of described small-sized air-core reactor 1, and the other end of described iron core oil-immersed type iron-core reactor 2 is connected to earth point.
In the present embodiment, as shown in Figure 3, described high voltage transformer neutral point is also provided with the resistor 3 be in series with described small-sized air-core reactor 1; Connect with one end of described resistor 3 in one end of described small-sized air-core reactor 1, the other end of described resistor 3 is connected to earth point.The now effect of resistor is equivalent to the iron core reactor under high-frequency, and resistor and small-sized air-core reactor all need to set the parameter met under high-frequency condition, can improve stability and insulating reliability over the ground.
In the present embodiment, preferably, in high-voltage fence, tens kHz and following low-frequency current are primarily of iron core reactor current limliting, and the electric current of 0.1MHz ~ 5GHz frequency range is primarily of little air-core reactor current limliting.Small reactor generally manufactures dry-type air-core reactor, but the insulating material of coil this should have buffer action to high-frequency current.The air-core reactor coil insulation majority run in present electrical network adopts insulating paper or chemical-fiber insulation material, and outdoor type is also wrapped up chemical-fiber insulation adhesive tape in addition and is coated with sun-proof paint; High-frequency current is caused to be penetrated by insulating material and paint, so small-sized air-core reactor manufacture must selected insulating material strict Controlling Technology.
In the present embodiment; not only relevant with a certain frequency range of circuit resonance point control in the selection of high voltage transformer neutral point series reactor reactance value; also to consider that protective relaying device setting value calculates the requirement to zero sequence impedance simultaneously, comprise the change of setting value.When carrying out the voltage high frequency feature measurement of relevant devices and carrying out the analysis of different frequency impedance data, answer special concern impedance maximum and minimum value, the frequency range of resonance point can be controlled thus better, be easy to select each reactor parameter.The model of series reactor is selected, and as profile and size, comprising the insulating material selection of coil windings and the control of turn-to-turn distance and rain and sun characteristic all has particular/special requirement.And, for the insulating material that reactor winding uses, whether can keep good insulation property at GHz frequency band or higher frequency section, improve the formula of insulation where necessary; Even can consider the better non-metallic inorganic compound insulating material of serviceability.In addition, except various electrical characteristic will be considered, but also the impact of outdoor sunray, typhoon, heavy rain to be considered.
The utility model increases small-sized air-core reactor in high-voltage fence, high-frequency resonance and the electromagenetic wave radiation problem of electrical network is alleviated with less investment, reduce high-frequency resonance current simultaneously, effectively can reduce the heating loss of transformer, improve transformer operational reliability and useful life, optimum facilitation is risen to the development of 500kV supergrid and 1000kV extra-high voltage grid from now on.
The foregoing is only preferred embodiment of the present utility model, all equalizations done according to the utility model claim change and modify, and all should belong to covering scope of the present utility model.
Claims (5)
1.500kV and above high voltage transformer neutral point current limiting device over the ground, it is characterized in that: comprise a high voltage transformer neutral point, described high voltage transformer neutral point is provided with small-sized air-core reactor, injects the high-frequency resonance current of ground network in order to be decreased through neutral point.
2. 500kV according to claim 1 and above high voltage transformer neutral point current limiting device over the ground, is characterized in that: described high voltage transformer neutral point is provided with the iron core oil-immersed type iron-core reactor be in series with described small-sized air-core reactor.
3. 500kV according to claim 2 and above high voltage transformer neutral point current limiting device over the ground, it is characterized in that: if described small-sized air-core reactor insulation level is lower than iron core oil-immersed type iron-core reactor, then connect with one end of described small-sized air-core reactor in one end of described iron core oil-immersed type iron-core reactor, and the other end of described small-sized air-core reactor is connected to earth point.
4. 500kV according to claim 2 and above high voltage transformer neutral point current limiting device over the ground, it is characterized in that: if described small-sized air-core reactor insulation level is higher than iron core oil-immersed type iron-core reactor, then connect with one end of described iron core oil-immersed type iron-core reactor in one end of described small-sized air-core reactor, and the other end of described iron core oil-immersed type iron-core reactor is connected to earth point.
5. 500kV according to claim 1 and above high voltage transformer neutral point current limiting device over the ground, is characterized in that: described high voltage transformer neutral point is also provided with the resistor be in series with described small-sized air-core reactor; Connect with one end of described resistor in one end of described small-sized air-core reactor, the other end of described resistor is connected to earth point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520329149.4U CN204615376U (en) | 2015-05-21 | 2015-05-21 | 500kV and above high voltage transformer neutral point current limiting device over the ground |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520329149.4U CN204615376U (en) | 2015-05-21 | 2015-05-21 | 500kV and above high voltage transformer neutral point current limiting device over the ground |
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| CN204615376U true CN204615376U (en) | 2015-09-02 |
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| CN201520329149.4U Expired - Fee Related CN204615376U (en) | 2015-05-21 | 2015-05-21 | 500kV and above high voltage transformer neutral point current limiting device over the ground |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111614116A (en) * | 2020-06-18 | 2020-09-01 | 南方电网科学研究院有限责任公司 | Grounding method and device of flexible direct current system |
-
2015
- 2015-05-21 CN CN201520329149.4U patent/CN204615376U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111614116A (en) * | 2020-06-18 | 2020-09-01 | 南方电网科学研究院有限责任公司 | Grounding method and device of flexible direct current system |
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Granted publication date: 20150902 |
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| CF01 | Termination of patent right due to non-payment of annual fee |