CN102445582B - Primary current sensor structure suitable for high-voltage direct current measurement - Google Patents
Primary current sensor structure suitable for high-voltage direct current measurement Download PDFInfo
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- CN102445582B CN102445582B CN201110367909.7A CN201110367909A CN102445582B CN 102445582 B CN102445582 B CN 102445582B CN 201110367909 A CN201110367909 A CN 201110367909A CN 102445582 B CN102445582 B CN 102445582B
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Abstract
The invention discloses a primary current sensor structure suitable for high-voltage direct current measurement. The structure comprises a first tubular bus bar section and a second tubular bus bar section both extending towards two ends, a feed-through Rogowski coil fixed on the second tubular bus bar section by a clamp, and a shunt connected with the Rogowski coil through a signal line. One end of the shunt is in rigid connection with the first tubular bus bar section while the other end thereof is connected with the second tubular bus bar section through a plurality of soft copper connecting sheets, and the first tubular bus bar section and the second tubular bus bar section are in rigid connection through a plurality of connecting strips. The primary current sensor structure provided by the invention has high output accuracy, strong interference rejection, simple structure, small volume, light weight and low manufacturing cost.
Description
Technical field
The present invention relates to a kind of primary current sensor, relate in particular to a kind of primary current sensor structure that high voltage direct current is measured that is applicable to, belong to high-voltage direct current field of measuring technique.
Background technology
Along with the development of direct current transportation, the measuring technique of high voltage direct current flow becomes new research direction.Traditional high voltage direct current flow sensor is to utilize electromagnetic induction principle, need additional accessory power supply, its transient characterisitics are poor, be subject to that external electromagnetic field disturbs, antisaturation ability, and the rising with electric pressure, the difficulty that its insulation realizes becomes how much multiples to increase with cost, therefore study the needs that novel high voltage direct current sensor becomes electric power development.
Electronic Current Transformer Applied in HVDC in conjunction with modern fiber optic conduction technology adopts " shunt+Luo-coil+Optical Fiber Transmission " technology, the mutual inductor of relative traditional electrical magnetic induction principle, there is following advantage: 1. shunt is not disturbed by external electromagnetic field, and measuring accuracy and degree of stability are high; 2. Luo-coil is not subject to DC component influence, can effectively measure the harmonic current in straight-flow system; 3. the application of the technology of fiber optic conduction has solved a difficult problem for signal high and low pressure side isolation on the one hand, can make on the other hand the harmless transmission of measuring-signal, has improved measuring accuracy.Above advantage makes this mutual inductor be highly suitable for HVDC (High Voltage Direct Current) transmission system, and it is mainly comprised of 4 parts: primary current sensor, primary transducer, signal transmission system and merge cells.
The core of this measuring system is primary current sensor, and it is output as extremely faint mV magnitude voltage signals, and its structure division is larger on its output accuracy impact, is that straight-flow system is measured the difficult problem realizing.
Summary of the invention
The object of this invention is to provide a kind of measuring primary current sensor structure of high-voltage direct current that is applicable to, it has overcome the defect of traditional sensors, and output accuracy is high, interference performance is strong, simple in structure, volume is little, lightweight, low cost of manufacture.
To achieve the object of the present invention, the technical scheme adopting is:
Be applicable to the primary current sensor structure that high voltage direct current is measured, it is characterized in that, comprise
The first paragraph tube type bus and the second segment tube type bus that to two ends, extend,
By clip, be fixed on the Luo-coil of the punching on described second segment tube type bus,
The shunt being connected with described Luo-coil by signal wire,
One end of described shunt and described first paragraph tube type bus are rigidly connected, and the other end is connected with described second segment tube type bus by many soft copper braces, and described first paragraph tube type bus and described second segment tube type bus are rigidly connected by many connection straps.
Described shunt is mouse cage type structure, and two ends are respectively copper dish, between two copper dishes, by many solid copper-manganese rods, is connected, and primary current is from the electric current incoming end access of the described copper dish at two ends, and output signal line is drawn from described copper dish circle centre position.
The copper dish of described first paragraph tube type bus and described shunt one end is rigidly connected by a ring flange, after described second segment tube type bus and another ring flange are rigidly connected, flexibly connect with described soft copper brace one end, the copper dish of the described soft copper brace other end and the described shunt other end flexibly connects again.
A described ring flange and described another ring flange are rigidly connected by many connection straps.
Described Luo-coil is for adopting outer integration type, and aluminum hull encapsulation, is fixed on described second segment tube type bus by aluminum clip.
Described shunt horizontal direction arranges, and the described connection strap that is positioned at below is provided with for supporting the boss that flexibly connects end of described shunt.
Also comprising one is fixed on, on a described ring flange and described another ring flange, sensor is played to the stainless steel outer cover of protection.
Also comprise two aluminum grading rings, described grading ring is fixed on described stainless steel outer cover.
Described signal wire is outwards drawn by stainless steel threaded line pipe.
Described connection strap is stainless steel connection strap.
Described tube type bus is aluminum tube type bus, and described ring flange is aluminium matter ring flange, and described shunt two ends are copper dish, when described shunt, described soft copper brace are connected with described ring flange, at its faying face, the transition bed that one copper-aluminium transition material forms is set.
The solution of the present invention main points are: 1. by having analyzed shunt characteristics design, be applicable to the measuring mouse-cage type diversion structure of high voltage direct current; 2. by having analyzed the measuring principle of Luo-coil and having manufactured critical process and designed outer integration type Luo-coil structure; 3. the shunt designing, Luo-coil and conductive connection part are divided and be combined into primary current sensor, by analyzing the factors such as temperature rise impact, external magnetic field interference, stress influence, outdoor protection, its structure is optimized to design.
Feature of the present invention is: by " mouse-cage type shunt+outer integration type Luo-coil " the commercial measurement magnitude of current, shunt is surveyed direct current, and Luo-coil is surveyed harmonic wave, and soft copper connects absorption stress influence, the use of copper-aluminium transition material, and soft copper connection absorbs stress.
The beneficial effect that the present invention produces:
The measuring primary current sensor structure of high-voltage direct current that is applicable to of the present invention, has that output accuracy is high, interference performance is strong, simple in structure, volume is little, a significant advantage such as lightweight, low cost of manufacture.
Primary current sensor basic structure is that two ends adopt aluminum tube female, and shunt connects left side pipe mother and soft copper, and it is female that the other end of soft copper connects right side pipe, and punching Luo-coil is enclosed within on the aluminum tube mother away from shunt one end.Measuring technique based on " mouse-cage type shunt+outer integration type Luo-coil ", has improved anti-external magnetic field interference performance, the antisaturation ability of direct current measurement, has promoted the measuring accuracy of harmonic wave.Shunt adopts the copper-manganese resistance of mouse-cage type structure to manufacture, and simple in structure, under natural cooling condition, heat dispersion is good, and the harmonic wave kelvin effect during to fault has good inhibiting effect; Luo-coil adopts outer integration type, has effectively avoided the magnetic saturation phenomenon in fault current situation, has good Frequency Response; Center is drawn the mode of wiring and has effectively been avoided the interference of magnetic field, high-pressure side to weak electric signal; The mode that soft copper connects has well absorbed the measuring error that shunt temperature rise differential expansion stress brings, and improves direct current measurement precision; The galvanic corrosion of Cu and Al combination face has effectively been avoided in the use of copper-aluminium transition material.Primary current sensor structural design after optimization, has stable high-precision output and good stability, by testing its direct current output accuracy, reaches 0.2 grade, and harmonic current output accuracy reaches 1 grade, meets the measurement requirement of the high-voltage direct current magnitude of current.
Accompanying drawing explanation
Fig. 1 is mouse-cage type diversion structure figure;
Mode of connection schematic diagram is drawn at the center of Fig. 2 shunt signal wire;
Fig. 3 is Luo-coil structural representation;
Fig. 4 is primary current sensor sectional view.
Embodiment
Below in conjunction with accompanying drawing, the invention will be further described.Following examples are only for technical scheme of the present invention is more clearly described, and can not limit the scope of the invention with this.
As shown in Figure 1, the shunt that direct current measurement of the present invention unit makes for copper-manganese resistance, it has good temperature characteristics, by electric resistance partial pressure principle survey direct current.Shunt 1A of the present invention is designed to 4 end resistance, and its potential end output voltage is directly proportional to primary current, and structure is mouse-cage type: two ends are red copper dish 1, and centre is many solid copper-manganese resistor rods 2.Copper dish current input terminal 3 accesses of primary current from two ends copper dish 1, secondary output voltage is drawn near the current potential exit 4 of circle centre position from copper dish 1 outside, two ends, and wherein the signal wire of positive ends is drawn by center pit 5.
Mouse-cage type shunt has the following advantages: 1. area of dissipation is large, good heat dissipation effect; 2. effectively eliminate the kelvin effect of harmonic current under failure condition; 3. be applicable to horizontal direction and install, both reduced the uneven thermoelectrical potential error causing of heat radiation, be convenient to again be connected in series in Primary Conductor loop; 4. inductance is little, and step response is good.
Because mutual inductor application scenario is in outdoor high-voltage large current environment, on-the-spot electromagnetic interference (EMI) is comparatively serious, in order to reduce the impact of alternating magnetic field on measuring accuracy.Taked following measures: shunt signal wire adopts Shielded Twisted Pair, screen layer and Primary Conductor equipotential; To being subject to the exposed signal wire at current potential exit 4 two ends of external magnetic field interference, partly do special processing, the mode of connection that draw at employing center.
The mode of connection that draw at center is as shown in Figure 2: the cabling copper pipe 15 that increases by one section of single-ended insulation at shunt central shaft, for preventing shunt short circuit, its port near shunt positive ends P1 is by teflon insulation sleeve pipe 13 and 1 insulation of shunt copper dish, the red heart yearn 11 of Shielded Twisted Pair 19 is connected to shunt positive ends P1 through cabling copper pipe 15, and the black heart yearn 17 of Shielded Twisted Pair 19 and screen layer 18 are connected to the negative polarity end P2 of shunt; For preventing that signal wire is aging, lose insulation, the signal wire in cabling copper pipe 15 is partly with varnished tube 14 parcels, and the wire hole position at its two ends covers with epoxy resin 12,16.The mode of connection of signal wire is drawn at this center can eliminate the impact of alternating magnetic field on signal wire, greatly improves the anti-interference of shunt.
As shown in Figure 3, harmonic measure of the present invention unit is Luo-coil 2A, by enameled wire, be evenly wound on ring skeleton and make, skeleton adopts nonferromugnetic material, its relative permeability is identical with airborne relative permeability, and this is the notable feature that air core coil is different from conventional iron core type coil.
From Faraday's electromagnetic induction law, when the magnetic flux of the coil through certain area changes, on this coil, can sense a certain size voltage, the direction of this voltage is relevant with the direction of the variation of magnetic flux, and the size of this induced voltage voltage is d Φ/dt.The structure Luo-coil shown in Fig. 2 of take is example, and its skeleton cross section is rectangle, the magnetic flux on single-turn circular coil and can be expressed as with mathematic(al) representation:
The inside radius that in above formula, a and b are skeleton and external radius; ω is the thickness of Luo-coil; B
xmagnetic induction density for the distance center axle any point that is x; μ
0for the magnetic permeability in vacuum.
The number of turns of Luo-coil is N, and the induced voltage e of Luo-coil can be represented by the formula, and in formula, M is known as the coefficient of mutual inductance of Luo-coil.
By just can reduce tested current signal i (t) to the integration of Luo-coil output voltage.
From above formula, induced voltage e is only relevant with the harmonic component of measured DC, and with DC component irrelevant (dI/dt of DC component is 0), it is the less harmonic component of accounting example in tested electric current, can be by the structural parameters of design Luo-coil sensor, obtain larger induction coefficient, and be not subject to the impact of DC component.The advantage that this is outstanding, has solved traditional mutual inductor working point relevant with DC component size, thereby cannot measure a difficult problem for a small amount of harmonic wave in D.C. high-current.
Luo-coil volume is little, simple in structure, the requirement reliably and with long-term of applicable power system measuring; While, dynamic perfromance was good without any ferromagnetic material in Luo-coil; Electronic mutual inductor is converted to light signal by high-pressure side change-over circuit by its secondary output, does not just have complicated High-Voltage Insulation design problem for Luo-coil; Above advantage, makes Luo-coil be suitable as very much high voltage direct current harmonic current sensing element.
As shown in Figure 4, primary current sensor structure of the present invention comprises: shunt 1A, Luo-coil 2A, a set of clip that is used for fixing coil 33, two aluminum tube type bus 34,35,12 soft copper braces of six roots of sensation stainless steel connection strap 36, stainless steel outer cover 37, two aluminum tube type bus connect the parts such as the ring flange 38 of use, two aluminum grading rings 39, two signal wires 310, corrugated stainless steel tubing 311, outer cover gib screw 312 and other fixing screws that connect shunt 1A and Luo-coil 2A, pad.
The basic structure that conductive connection part divides is: two ends adopt aluminum tube type bus 34, left side tube type bus 34 is welded with left side ring flange 38, left side ring flange 38 flexibly connects by bolt and soft copper brace 36 left sides, the right side of soft copper brace 36 flexibly connects by the left side copper dish 1 of bolt and shunt 1A, shunt 1A right side copper dish 1 is rigidly connected by bolt and right side flange coil pipe 38, right side ring flange 38 is with right side tube type bus 34 by being welded and fixed, and the ring flange 38 at two ends is rigidly connected by stainless steel connection strap 35.
Concrete connected mode is as follows:
1) tube type bus 34 of sensor.Install at scene for ease of sensor, and this part conductor that sensor externally connects adopts conventional aluminium alloy cast bus in straight-flow system; For guaranteeing its through-current capability and strengthening heat-exchange capacity, in the present embodiment, tube type bus internal diameter is designed to 180mm, and external diameter is designed to 200mm; For guaranteeing enough physical strengths, during the on-the-spot installation of tube type bus, must use the mode of welding bushing pipe in clip, pipe to be connected with straight-flow system bus.
2) tube type bus 34 and ring flange 38.For guaranteeing the reliable connection of each current-carrying part of sensor, a ring flange 38 of joint welding of every section of tube type bus 34, for connection, fixed shunt 1A, soft copper brace 36 and stainless steel connection strap 35 etc.; For guaranteeing that weld conductive characteristic is better than tube type bus 34 itself, prevent that junction contact resistance is excessive and cause sensor temperature rise aggravation, tube type bus 34 and the faying face of ring flange 38 have adopted the technique of multilayer argon arc welding.
3) ring flange 38 and shunt 1A's is connected.Shunt 1A is copper material, and ring flange 38 is aluminium material, and this bi-material direct conduction connects can produce galvanic corrosion effect, and the reliability that conduction is connected and life-span produce considerable influence.For this reason, must increase copper-aluminium transition material at both faying faces; For preventing aluminum oxidation and reducing the fever phenomenon that contact resistance brings, when transition material is installed, aluminium surface also must adopt the measure of polishing coating conductive paste in addition.
4) ring flange 38 and soft copper brace 36 is connected.Between ring flange 38 and soft copper brace 36, also need to increase copper-aluminium transition material and avoid galvanic corrosion; For guaranteeing that this part connects through-current capability, both faying faces must be greater than the sectional area of 2 times of tube type bus in addition.
5) soft copper brace 36 and shunt 1A.Both are copper material, can directly connect, and total contact area is identical while being connected with ring flange 38.
Listed the structural design that improves several places key of primary current sensor measuring accuracy below:
1) in order effectively to prevent that copper-manganese resistor rod 2 from answering temperature rise to produce internal stress, cause change in resistance, affect measuring accuracy, shunt 1A adopts one end to fix, the mode of soft copper brace 36 connections for the other end.Specific constructive form is as Fig. 4: the ring flange 38 of both sides forms a rigid frame by six roots of sensation stainless steel connection strap 35; Shunt 1A right side is secured by bolts in right side ring flange 38, and its left side is unsettled; Between left side ring flange 38 and the left side of shunt 1A, 12 soft copper braces 36 are installed; When shunt 1A produces the differential expansion stress of horizontal direction due to temperature rise, soft copper brace 36 can absorb by the free-extension in rigid frame this stress like this.
2) for reducing the impact on copper-manganese resistor rod 2 of gravity vertically downward, on the connection strap 35 below, design the downward free end that boss supports shunt 1A, eliminate gravity effect.
3) for improving harmonic measure precision, make the center of primary current through Luo-coil 2A, specialized designs clip 33 the Luo-coil 2A of aluminum hull encapsulation is fixed on the tube type bus 34 away from shunt 1A one end.
4) impaired for preventing signal wire, the shunt 1A being made by Shielded Twisted Pair and the signal wire 310 of Luo-coil 2A are outwards drawn by stainless steel threaded line pipe 311.
5) for to prevent that long-term outdoor operation from suffering the destruction of external carbuncle, sensor has also designed stainless steel outer cover 37, and fixing with ring flange 38 by bolt 312.
6) for preventing, in the excessive sensor that causes of high-pressure side local field strength, puncture, aluminum grading ring 39 has been designed at sensor two ends, and is screwed on stainless steel outer cover 7.
HVDC (High Voltage Direct Current) transmission system primary current sensor direct current measurement precision according to above Technical Design can reach 0.2 grade, and harmonic measure precision can reach 1 grade.
Above embodiment only, for explanation technological thought of the present invention, can not limit protection scope of the present invention with this, the technological thought that everything proposes according to the present invention, and any change of doing on technical scheme basis, within all falling into protection domain of the present invention.
Claims (7)
1. be applicable to the primary current sensor structure that high voltage direct current is measured, it is characterized in that, comprise
Tube type bus, described tube type bus comprises first paragraph tube type bus and the second segment tube type bus extending to two ends,
By clip, be fixed on the Luo-coil of the punching on described second segment tube type bus,
The shunt being connected with described Luo-coil by signal wire,
Described shunt is mouse cage type structure, and two ends are respectively copper dish, between two copper dishes, by many solid copper-manganese rods, is connected, and primary current is from the electric current incoming end access of the described copper dish at two ends, and signal wire is drawn from described copper dish circle centre position;
One end of described shunt and described first paragraph tube type bus are rigidly connected, and the other end is connected with described second segment tube type bus by many soft copper braces, and described first paragraph tube type bus and described second segment tube type bus are rigidly connected by many connection straps;
The copper dish of described first paragraph tube type bus and described shunt one end is rigidly connected by a ring flange, after described second segment tube type bus and another ring flange are rigidly connected, flexibly connect with described soft copper brace one end, the copper dish of the described soft copper brace other end and the described shunt other end flexibly connects again; The faying face of described another ring flange and described soft copper brace must be greater than the sectional area of 2 times of tube type bus;
Described shunt horizontal direction arranges, and the described connection strap that is positioned at below is provided with for supporting the boss flexibly connecting of described shunt.
2. a kind of primary current sensor structure that high voltage direct current is measured that is applicable to according to claim 1, it is characterized in that, described first paragraph tube type bus and described second segment tube type bus are rigidly connected and are specially a described ring flange and described another ring flange is rigidly connected by many connection straps by many connection straps.
3. a kind of primary current sensor structure that high voltage direct current is measured that is applicable to according to claim 1, is characterized in that, described Luo-coil is for adopting outer integration type, and aluminum hull encapsulation, is fixed on described second segment tube type bus by aluminum clip.
4. a kind of primary current sensor structure that high voltage direct current is measured that is applicable to according to claim 1, is characterized in that, also comprises one and is fixed on, on a described ring flange and described another ring flange, sensor is played to the stainless steel outer cover of protection.
5. a kind of primary current sensor structure that high voltage direct current is measured that is applicable to according to claim 4, is characterized in that, also comprise two aluminum grading rings, described grading ring is fixed on described stainless steel outer cover.
6. a kind of primary current sensor structure that high voltage direct current is measured that is applicable to according to claim 1, is characterized in that, described signal wire is outwards drawn through stainless steel threaded line pipe.
7. a kind of primary current sensor structure that high voltage direct current is measured that is applicable to according to claim 1, it is characterized in that, described tube type bus is aluminum tube type bus, described ring flange is aluminium matter ring flange, described shunt two ends are copper dish, when described shunt, described soft copper brace are connected with described ring flange, at its faying face, the transition bed that one copper-aluminium transition material forms is set.
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Cited By (1)
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| CN110352356A (en) * | 2017-02-15 | 2019-10-18 | Koa株式会社 | Shunt resistance device and the current detection means for using shunt resistance device |
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| CN103257260B (en) * | 2012-10-24 | 2017-02-08 | 惠州市惠之声实业有限公司 | Method for resisting alternating magnetic field interference and sample resistor |
| FR2998376B1 (en) * | 2012-11-16 | 2015-07-31 | Alstom Technology Ltd | VERY HIGH VOLTAGE LINE VOLTAGE SENSOR WITH CONTINUOUS CURRENT |
| CN106526272B (en) * | 2016-09-24 | 2020-02-21 | 北京东方计量测试研究所 | Precise shunt |
| CN107121574A (en) * | 2017-05-11 | 2017-09-01 | 南京南瑞继保电气有限公司 | A kind of DC current current divider |
| CN109782062A (en) * | 2017-11-10 | 2019-05-21 | 许继集团有限公司 | A kind of Rogowski coil type electronic current mutual inductor harmonic wave meter characteristic optimization method |
| JP6738857B2 (en) * | 2018-06-06 | 2020-08-12 | 矢崎総業株式会社 | Sensor protector |
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| CN112748274B (en) * | 2019-10-31 | 2023-05-16 | 西安西电高压开关有限责任公司 | Current measuring device |
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Address after: High road high tech Development Zone Nanjing city Jiangsu province 210061 No. 20 Co-patentee after: NARI Group Corp. Patentee after: NARI TECHNOLOGY Co.,Ltd. Address before: High road high tech Development Zone Nanjing city Jiangsu province 210061 No. 20 Co-patentee before: NARI Group CORPORATION STATE GRID ELECTRIC POWER INSTITUTE Patentee before: NARI TECHNOLOGY Co.,Ltd. |