CN200941556Y - Neutral point non-linear voltage limiting earthing device - Google Patents
Neutral point non-linear voltage limiting earthing device Download PDFInfo
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- CN200941556Y CN200941556Y CN 200620071344 CN200620071344U CN200941556Y CN 200941556 Y CN200941556 Y CN 200941556Y CN 200620071344 CN200620071344 CN 200620071344 CN 200620071344 U CN200620071344 U CN 200620071344U CN 200941556 Y CN200941556 Y CN 200941556Y
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- neutral point
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- pressure limiting
- linear pressure
- earthing device
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Abstract
A neutral point non-linear voltage limitation grounding device, characterized in that a high energy oxidized zinc piezo varistor series RV is formed by series connection of a plurality of oxidized zinc piezo varistor series; The high energy oxidized zinc piezo varistor series RV, a current limitation fuse and a large power even current resistor R commonly forms a high energy none-linear voltage limitation component in series connection; At least four groups of high energy none-linear voltage limitation component which are connected in parallel forms the grounding device, one end of the grounding device is connected to the neutral point of the system, another end is grounded. The utility model reduces over voltage of none effective grounding system, improves the reliability of power supply of effective grounding system, reduces grounding current of single phase and improves safety of human body.
Description
Technical field:
The utility model relates to a kind of non-linear pressure limiting earthing device of neutral point that is applied to electric power system.
Technical background
The earthing mode of electric power system relates to the major issue of all many-sides such as the input amount, user security of reliability, the construction fund of safe operation, the power supply of electrical network; Relate to numerous areas such as overvoltage and insulation coordination, relaying protection, electromagnetic compatibility in electric power system inside.At present, system earth mode is mainly divided four kinds of two classes:
1, direct ground connection and the low resistance grounding in the earthing mode.
2, earth-free and resonance grounding and the high resistance ground in the non-effective earthing mode.
More than four kinds of earthing modes all have certain pluses and minuses, be described as follows:
The neutral-point solid ground mode:
1, is applicable to above high pressure of 110KV and 0.4KV low-pressure system.
2, during single phase ground fault, non-fault phase voltage raises minimum.
3, communication electronic equipment is disturbed maximum.
4, single-phase-to-ground current maximum.
Neutral point is through the low resistance grounding mode:
1, the abnormal overvoltage in the time of can be with single-phase earthing is suppressed at below 2.8 times of phase voltage of operation, and electrical network can adopt the lower electric equipment of insulation level.
2, can excise single phase ground fault fast.
3, communication electronic equipment is disturbed greatly.
4, improve the electric equipment operation condition, improved the reliability of equipment operation.
5, relaying protection is simple.
6, single-phase-to-ground current is bigger, and the redundant investment of system line is higher.
Neutral point is through the resonance grounding mode of arc suppression coil:
1, the operational reliability of electrical network is higher.
2, to the blow-out voluntarily of transient fault single-phase earthing, be difficult for developing into three-phase shortcircuit.
3, can reduce fault current, improve Personal Safety.
4, when system capacitive current surpasses 30A, the arc suppression coil capacity increases, and increases investment.
5, in the handling failure process circuit operated a switch one by one and may produce higher overvoltage.
6, the manual detection and the required time of fixing a breakdown longer, expansion accident easily.
7, the relaying protection computing is complicated.
Isolated neutral system seldom uses in China at present because of very easily producing resonance and overvoltage injury.
As can be seen; all there are certain pluses and minuses in various earthing modes; from suppressing overvoltage, reduce apparatus insulated level, improving the angle of reliability of relay protection; adopt the effective grounding mode better; but from improving power supply reliability; improve personal device security, reduce the angle of electromagnetic interference and see that employing non-effective earthing mode is better.Therefore the earthing mode of electrical network usually becomes needs and weighs the selection that many-sided problem just can be made a decision, up to the present the superiority-inferiority of above-mentioned earthing mode still has very big dispute, thus the present situation that multiple earthing mode in electric power system, occurred and deposited.
In the neutral resistor grounding system of routine; because influence determines that the factor of neutral resistance R resistance and power is a lot; fault current, power-frequency overvoltage, relaying protection cooperation and communication interference-limited during as system's total capacitance electric current, single phase ground fault or the like; concern complexity between they and the neutral resistance resistance; show as the strong nonlinear relation, can't represent with simple equation formula.At present to the neutral point of city 10KV distribution system on the determining of low resistance grounding mode; adopt conventional method to carry out mostly; promptly start with from the situation of system's generation single phase ground fault; constantly change the neutral resistance value; stable state and transient state two aspects to system are calculated; the single-phase earth fault current value of Gai Bianing more thereupon; single phase ground fault perfects phase voltage value and arc grounding overvoltage value; ferro-resonance over-voltage value or the like; binding occurrence according to aspects such as rules setting and relaying protections comprehensively compares then; finally draw more suitable grounding resistance; but; this procedure is loaded down with trivial details; complicated; and require the designer to have certain engineering experience, and be difficult to obtain the optimum value of earth resistance.
Summary of the invention:
The utility model is for avoiding above-mentioned existing in prior technology weak point, provide a kind of neutral point non-linear pressure limiting earthing device, to reduce the overvoltage in the non-effectively earthed system, the power supply reliability of raising effectively earthed system, reduce single-phase-to-ground current, thereby to the interference of communication and other electric equipments, improve the personal safety performance when reducing ground connection.
The technical scheme that the utility model technical solution problem is adopted is:
Design feature of the present utility model is
A, constitute high energy by multi-disc Zinc-oxide piezoresistor serial connection and hold Zinc-oxide piezoresistor string RV;
B, hold Zinc-oxide piezoresistor string RV and current limiting fuse FU, and high-power flows resistance R is connected in series formation high-energy non-linear pressure limiting assembly jointly by described high energy;
C, parallel with one another by the described high-energy non-linear pressure limiting of at least four groups assembly constitutes described earthing device, described earthing device one terminating systems neutral point, other end ground connection.
Design feature of the present utility model also is:
In described each bar high-energy non-linear pressure limiting assembly, current transformer TA is set respectively, and with the output signal of this current transformer TA detection signal as controller KZQ.
The metal cabinet is set, and all parts are installed in the described metal cabinet, and in described metal cabinet the humiture detection probe are set.
The utility model has adopted the mode of non-linear ground connection side, buffer action by nonlinear resistance when system normally moves, make system works in the non-effective earthing state, when overvoltage takes place, voltage inhibitory action by nonlinear resistance of the present utility model, make the neutral point potential shift be limited in reduced levels, thereby reduce system's overvoltage level significantly; When single-phase earthing takes place, by choose reasonable high energy ZnO operation voltage value, can guarantee that earth current is limited in very little level, system can not need trip and normal operation, and the power supply continuity of system is reliably guaranteed; Exist under the unbalanced situation at system voltage, the heating of self not consuming energy, but long-term stable operation are compared longer service life with the linear resistance cabinet of routine.
Compared with the prior art, the beneficial effects of the utility model are embodied in:
Resistance when 1, the utility model changes conventional neutral resistor and chooses and electric current are calculated as magnitude of voltage and calculate, and computational process is greatly simplified.The most important thing is: the earthing mode of electric power system is changed into the self-adjusting variable ground connection pattern of working state of system by original dead earth pattern, under the lower normal operating conditions of neutral point voltage, device is equivalent to the high resistant in the non-effectively earthed system, neutral point voltage raises when improper situation takes place in system, device is equivalent to small resistor more than raft value operation voltage, effectively suppress neutral point voltage amplitude and earth current, make system have the advantage of grounding system and non-effectively earthed system concurrently, reduce the great amount of investment of the circuit redundancy of grounding system, can be society and create a large amount of economic benefits.
2, the utility model volume is little, cost is low, and is simple in structure, dependable performance, and long service life is articulated on the neutral point of electric power system, can make the power system operation safety and reliability.
3, the utility model can be applicable to the upgrading of non-effectively earthed system in the electric power system, also can become the substitute of the linear earth resistance cabinet of the new projects of preparing the employing grounding system, has wide market application prospect.
Description of drawings:
Accompanying drawing is the utility model circuit theory diagrams.
Among the figure: TA is a current transformer; FU is a current limiting fuse; RV is a high energy ZnO resistors; R is high-power flows resistance; RV and R constitute high-energy non-linear pressure limiting assembly jointly; TS is a Temperature Humidity Sensor; KZQ is a controller.
Embodiment:
Referring to accompanying drawing, in the present embodiment, the high energy that is made of multi-disc Zinc-oxide piezoresistor serial connection holds Zinc-oxide piezoresistor string RV; Hold Zinc-oxide piezoresistor string RV and current limiting fuse FU by high energy, and high-power flows resistance R is connected in series formation high-energy non-linear pressure limiting assembly jointly; Wherein high-power current-sharing electric current R is a ceramic resistor: parallel with one another by at least four group high-energy non-linear pressure limiting assemblies again, constitute earthing device, a terminating systems neutral point of earthing device, other end ground connection.
In concrete the enforcement, in each bar high-energy non-linear pressure limiting assembly, current transformer TA is set respectively, and with the output signal of this current transformer TA detection signal as controller KZQ.
In concrete the enforcement; also the metal cabinet should be set; all parts are installed in the described metal cabinet; and in this metal cabinet, the humiture detection probe is set; on the surface of metal cabinet observable controller is set, thereby constitutes an autonomous device that neutral point is had complete pressure limiting ground protection function.
In circuit structure as shown in the figure:
Current transformer TA is used for the system neutral earth current is monitored, and current conversion is arrived the level that controller KZQ needs;
Current limiting fuse FU is used to protect this to install each branch road and when irrecoverable property fault occurring the corresponding failure branch road is kept apart from neutral point, prevents that thermal runaway from appearring in syndrome serial;
High energy ZnO resistors string RV is the main power component of pressure limiting energy-absorbing, and system neutral voltage is limited, and suppresses power-frequency voltage and other overvoltage;
High-power ceramic flows resistance R has the effect of three aspects:
1, is used to limit the maximum current that flows through high energy ZnO resistors string RV;
2, play current-sharing effect under the big current work state;
3, simplify the blade technolgy of joining of high energy ZnO resistors string RV;
5. humiture in the Temperature Humidity Sensor TS detecting box is sent to controller KZQ with the humiture data;
6. each branch road earth current of controller KZQ detection system writes down the relevant control command of also output.
Hold the threshold values (generally be defined as phase voltage value about 90%) of Zinc-oxide piezoresistor by choose reasonable high energy, the course of work of device mainly comprises two aspects: system protection operating state and self course of action.
The protection operating state:
1, during system's operate as normal, the neutral point displacement voltage value is far below the threshold values of piezo-resistance, blocked by high energy ZnO, system is in a kind of operational mode of non-effective earthing, and the nonlinear resistance that the various instantaneity overvoltage that produce in the system are all responded fast is limited in 2 times below the phase voltage;
2, when system's generation Single Phase Metal ground connection, the system neutral voltage of non-effectively earthed system can rise to the phase voltage level, but be connected to the system of this device, the neutral point voltage value is limited in by this device in 90% scope of phase voltage, and non-fault phase voltage raises and also is limited in 1.7 times below the phase voltage; Simultaneously, system's single-phase-to-ground current also device be limited in less level;
3, when system's generation arc grounding, neutral point displacement voltage might rise to high level, but because the voltage clamp effect of the high energy ZnO of neutral point, system voltage vibration additive process is subjected to operative constraint, arc energy is absorbed by high energy ZnO and high-power ceramic resistor, system neutral higher-order of oscillation energy also can effectively be absorbed, and the arc grounding overvoltage of system's normal phase can be effectively suppressed, and can reach the effect that the quickening arc light extinguishes speed to a certain extent;
4, when system's generation resonance, because the amplitude of neutral point voltage is limited by high energy ZnO resistors, oscillatory process is eliminated by very fast impair absorption.
Installing self course of action is described as follows:
After the utility model is put into system neutral, humiture data in each branch road earth current size of display controller KZQ detection system and the cabinet, after flowing through each branch current and reaching the action threshold values, device begins to judge the total earth current size of calculating, and the record start concluding time; After the earth current amplitude maintained more than the threshold current and surpasses setting time, device sent the grounding alarm signal; When each branch current difference value reaches when adjusting multiple, device sends the particular alarm signal.When device detected in-cabinet temperature above setting value, display controller started the forced heat radiation fan high-power resistance string is carried out air blast cooling.
Claims (3)
1, the non-linear pressure limiting earthing device of neutral point is characterized in that:
A, constitute high energy by multi-disc Zinc-oxide piezoresistor serial connection and hold Zinc-oxide piezoresistor string RV;
B, hold Zinc-oxide piezoresistor string RV and current limiting fuse FU, and high-power flows resistance R is connected in series formation high-energy non-linear pressure limiting assembly jointly by described high energy;
C, parallel with one another by the described high-energy non-linear pressure limiting of at least four groups assembly constitutes described earthing device, described earthing device one terminating systems neutral point, other end ground connection.
2, the non-linear pressure limiting earthing device of neutral point according to claim 1, it is characterized in that in described each bar high-energy non-linear pressure limiting assembly, current transformer TA is set respectively, and with the output signal of this current transformer TA detection signal as controller KZQ.
3, the non-linear pressure limiting earthing device of neutral point according to claim 1 and 2 is characterized in that being provided with the metal cabinet, and all parts are installed in the described metal cabinet, and in described metal cabinet humiture detection probe TS is set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620071344 CN200941556Y (en) | 2006-05-12 | 2006-05-12 | Neutral point non-linear voltage limiting earthing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620071344 CN200941556Y (en) | 2006-05-12 | 2006-05-12 | Neutral point non-linear voltage limiting earthing device |
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| CN200941556Y true CN200941556Y (en) | 2007-08-29 |
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| CN 200620071344 Expired - Fee Related CN200941556Y (en) | 2006-05-12 | 2006-05-12 | Neutral point non-linear voltage limiting earthing device |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103124063A (en) * | 2012-07-13 | 2013-05-29 | 中电普瑞科技有限公司 | Arrester overvoltage protection device with variable voltage ratio and implementation method |
| CN106443145A (en) * | 2016-08-30 | 2017-02-22 | 国网陕西省电力公司经济技术研究院 | Method for suppressing ferro-resonance by grounding of neutral point through ZnO non-linear resistor in power distribution network |
| CN110416987A (en) * | 2019-07-08 | 2019-11-05 | 国网天津市电力公司电力科学研究院 | Voltage transformer overvoltage inhibiting apparatus based on sensitive characteristic |
-
2006
- 2006-05-12 CN CN 200620071344 patent/CN200941556Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103124063A (en) * | 2012-07-13 | 2013-05-29 | 中电普瑞科技有限公司 | Arrester overvoltage protection device with variable voltage ratio and implementation method |
| CN103124063B (en) * | 2012-07-13 | 2015-05-13 | 中电普瑞科技有限公司 | Arrester overvoltage protection device with variable voltage ratio and implementation method |
| CN106443145A (en) * | 2016-08-30 | 2017-02-22 | 国网陕西省电力公司经济技术研究院 | Method for suppressing ferro-resonance by grounding of neutral point through ZnO non-linear resistor in power distribution network |
| CN106443145B (en) * | 2016-08-30 | 2018-11-30 | 国网陕西省电力公司经济技术研究院 | Power network neutral point is grounded the method for inhibiting ferromagnetic resonance through Zno varistor |
| CN110416987A (en) * | 2019-07-08 | 2019-11-05 | 国网天津市电力公司电力科学研究院 | Voltage transformer overvoltage inhibiting apparatus based on sensitive characteristic |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: ANHUI SAIPU ELECTRIC CO., LTD Free format text: FORMER OWNER: LI YAN Effective date: 20100504 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: ADDRESS; FROM: 230088 ROOM 409, TIANYIGUOJI BUSINESS CENTER, NO.669, CHANGJIANG WEST ROAD,HEFEI CITY, ANHUI PROVINCE TO: 238335 YAOGOU INDUSTRIAL DISTRICT, WUWEI COUNTY, CHAOHU CITY, ANHUI PROVINCE |
|
| TR01 | Transfer of patent right |
Effective date of registration: 20100504 Address after: 238335 Yao Gou Industrial Zone, Chaohu, Anhui, Wuwei County Patentee after: Anhui Saipu Electric Co., Ltd. Address before: 409, Tian Yi International Business Center, room 669, 230088 West Changjiang Road, Anhui, Hefei Patentee before: Li Yan |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20070829 Termination date: 20120512 |