CN204008864U - Power-frequency earthing impedance instrument - Google Patents
Power-frequency earthing impedance instrument Download PDFInfo
- Publication number
- CN204008864U CN204008864U CN201420435785.0U CN201420435785U CN204008864U CN 204008864 U CN204008864 U CN 204008864U CN 201420435785 U CN201420435785 U CN 201420435785U CN 204008864 U CN204008864 U CN 204008864U
- Authority
- CN
- China
- Prior art keywords
- transformer
- paraphase
- input end
- reometer
- utility
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
Abstract
Earthing device in the utility model electric system; power-frequency earthing impedance instrument specifically; it comprises the transformer that input end is connected with power supply; transformer has two groups of isolation output windings that electrical property is identical; the input end of this transformer is connected with a paraphase encryption circuit, output terminal is connected with Current Mutual Inductance circuit; on this mutual inductance circuit, be connected with reometer, described voltage table and reometer are all by another transformer-supplied of the described input end of access.The utility model is provided with independently reometer and voltage table, as long as the potential pole of earth mat earthing device and the electric current utmost point are accessed to this tester, and just can be fast regularly, genlocing measures the magnitude of voltage between output current value and grounded screen and the voltage pole of transformer; The utility model adopts paraphase device to carry out paraphase measurement, to eliminate the impact of uneven zero-sequence current, improves the accuracy of measuring.
Description
Technical field
The utility model relates to the earthing device in electric system, is power-frequency earthing impedance instrument specifically.
Background technology
At present, domestic earthing device is as weaker in the test job of generating plant, electric substation, electric power line pole tower etc. in electric system, and some crucial Technologies And Conceptions are fuzzyyer, and technological means falls behind.For above-mentioned present situation, China has worked out up-to-date industry standard DL/T475-2006 and standard GB/T/T17949.1-2000.New standard has done a lot of material alterations to old standard.In the time that earthing device is measured, owing to being subject to the various interference such as uneven zero-sequence current and radio frequency, make test result produce very large error.Particularly generally very little (generally below 0.5 Ω) of the impedance ground of large-scale grounding network, disturbs the relative error of bringing larger.
In order to reduce the on-the-spot impact of disturbing, earth loop impedance test equipment must adopt independent current source or measure through isolating transformer power supply mode, and the method adopting at present mainly contains two kinds, and one is to increase power frequency measuring current, and another kind is to use alien frequencies method.First method is to strengthen signal voltage and marking current by strengthening measuring current, thereby improves signal to noise ratio (S/N ratio), reduces measuring error.This method, owing to having adopted very large measuring current (DL/T475-2006 standard recommendation should not be less than 50A), makes equipment very heavy, and wiring labour intensity is very large, takes time and effort.Alien frequencies rule is that the frequency by changing measuring current is avoided power frequency interference, because signal frequency is different from interfering frequency, just can carry out by wave filter the impact of filtering interfering, thereby improve measuring accuracy.Alien frequencies method is because the measuring current adopting is less, and therefore equipment is small and exquisite, and wiring labour intensity also alleviates greatly.Owing to having advantages of that test result is reliable and stable and time saving and energy saving, the test of alien frequencies method is accepted extensively and is adopted by domestic and international expert.But according to definition, power-frequency earthing impedance refers to the impedance that earthing device presents under power current, and the measuring current frequency that alien frequencies method adopts is not power frequency, and the numerical value therefore recording will have deviation with the value that records under power current.The isolation method of alien frequencies power supply and electric pressure also can exert an influence to test accuracy, theory and practice shows, the reason that produces deviation is that the impedance ground of earthing device is complex impedance, not only comprise resistive component, also contain the inductive relevant with frequency and capacitive component.The test frequency and the power frequency that adopt differ that more equivalence is poorer, and measuring error is larger.
Utility model content
For above-mentioned technical matters, the utility model provides a kind of measurement simple, accurate, and measures the low power-frequency earthing impedance instrument of cost.
The technical scheme in the invention for solving the above technical problem is: power-frequency earthing impedance instrument; comprise the transformer that input end is connected with power supply; transformer output terminal is connected with the electric current utmost point of earth mat earthing device; the potential pole of earth mat earthing device is connected with voltage table; it is characterized in that: the input end of this transformer is connected with a paraphase encryption circuit, output terminal is connected with Current Mutual Inductance circuit; on this mutual inductance circuit, be connected with reometer, described voltage table and reometer are all by another transformer-supplied of the described input end of access.
As preferably, described transformer is provided with two isolation output terminals.
As preferably, described paraphase encryption circuit forms loop by paraphase device, relay.
As preferably, described paraphase device is the selector switch and two contactors that are connected with this switch being arranged in described loop.
As preferably, described paraphase device is the switch that is arranged on described transformer input end.
As preferably, on described reometer and voltage table, be provided with measured data values synchronous locking circuit.
As can be known from the above technical solutions, the utility model is provided with independently reometer and voltage table, as long as the potential pole of earth mat earthing device and the electric current utmost point are accessed to this tester, just can be fast timing, genlocing measure the magnitude of voltage between output current value and grounded screen and the voltage pole of transformer, its circuit connects simple, intuitive display; The utility model adopts paraphase timing circuit not only can carry out phase transition metering system, to eliminate the impact of uneven zero-sequence current, improves the accuracy of measuring, and can control startup, stops etc.
Brief description of the drawings
Fig. 1 is that the utility model is measured structured flowchart;
Fig. 2 circuit diagram of the present utility model;
Fig. 3 another kind of map of current of the present utility model.
Embodiment
Introduce in detail power-frequency earthing impedance instrument of the present utility model below in conjunction with Fig. 1, it comprises the transformer 1 that input end is connected with power supply, this transformer must adopt high-effect transformer, transformer output terminal is connected with the electric current utmost point of earth mat earthing device 2, the potential pole of earth mat earthing device is connected with voltage table 3, the input end of this transformer is connected with a paraphase encryption circuit 4, output terminal is connected with Current Mutual Inductance circuit 5, on this mutual inductance circuit, be connected with reometer 6, described voltage table and reometer are all powered by another transformer 7 that accesses described input end; Paraphase encryption circuit not only can carry out phase transition metering system, to eliminate the impact of uneven zero-sequence current, improves the accuracy of measuring, and can control startup, stops etc.; Described paraphase encryption is by relay, paraphase installation composition loop.
In the utility model, as Fig. 2, described paraphase device is the switch HY that is arranged on described transformer input end, and itself and knob, timing relay, contactor etc. form encryption loop, can make like this circuit simple, and cost is low, easy to operate.As another kind of mode, as Fig. 3, described paraphase device is the selector switch SB1 and two contactor KM1, KM2 being connected with this switch being arranged in described loop, is closed, is stopped and the conversion of input supply voltage polarity, easily operation by a switch.
In the utility model, transformer has two groups of isolation output windings that electrical property is identical, thereby can form identical two the isolation output terminals of electrical quantity, its exportable three kinds of different voltages, as the voltage of input 380V, by exportable two the single approximately 400V voltages of this transformer, also the 400V voltage of exportable 2 series connection, also exportable 2 400V voltages in parallel, thus three kinds of different power stages are provided, to be suitable for different measurement environment.
In implementation process, on described reometer and voltage table, be provided with measured data values synchronous locking circuit, can, by the voltage and current numerical value genlocing of measuring, facilitate staff intuitively to read and Taking Pictures recording.Timing relay of the present utility model ensures the electrical safety of the high-power output running status of transformer.The utility model is provided with independently reometer and voltage table, as long as the potential pole of earth mat earthing device and the electric current utmost point are accessed to this tester, just can measure fast electric current and magnitude of voltage, and measurement is simple, cost is lower.
Above-mentioned embodiment is only for illustration of the utility model, and be not to restriction of the present utility model, the those of ordinary skill in relevant technologies field, in the situation that not departing from the utility model spirit and scope, can also make various variations and modification, therefore all technical schemes that are equal to also should belong to category of the present utility model.
Claims (6)
1. power-frequency earthing impedance instrument; comprise the transformer that input end is connected with power supply; transformer output terminal is connected with the electric current utmost point of earth mat earthing device; the potential pole of earth mat earthing device is connected with voltage table; it is characterized in that: the input end of this transformer is connected with a paraphase encryption circuit, output terminal is connected with Current Mutual Inductance circuit; on this mutual inductance circuit, be connected with reometer, described voltage table and reometer are all by another transformer-supplied of the described input end of access.
2. tester according to claim 1, is characterized in that: described transformer is provided with two isolation output terminals.
3. tester according to claim 1, is characterized in that: described paraphase encryption circuit forms loop by paraphase device, relay.
4. tester according to claim 3, is characterized in that: described paraphase device is the selector switch and two contactors that are connected with this switch being arranged in described loop.
5. tester according to claim 3, is characterized in that: described paraphase device is the switch that is arranged on described transformer input end.
6. tester according to claim 1, is characterized in that: on described reometer and voltage table, be provided with measured data values synchronous locking circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420435785.0U CN204008864U (en) | 2014-08-04 | 2014-08-04 | Power-frequency earthing impedance instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420435785.0U CN204008864U (en) | 2014-08-04 | 2014-08-04 | Power-frequency earthing impedance instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204008864U true CN204008864U (en) | 2014-12-10 |
Family
ID=52048843
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420435785.0U Expired - Fee Related CN204008864U (en) | 2014-08-04 | 2014-08-04 | Power-frequency earthing impedance instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204008864U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104897968A (en) * | 2015-05-14 | 2015-09-09 | 武汉市康达电气有限公司 | Method for testing impedance of earth screen based on phase-inversion incremental method |
| CN105699784A (en) * | 2016-03-16 | 2016-06-22 | 国家电网公司 | Device for measuring grounding grid resistance by using voltage superposition method |
| CN108767984A (en) * | 2018-06-06 | 2018-11-06 | 中国铁路设计集团有限公司 | A kind of traction institute earth mat intelligent monitoring device |
-
2014
- 2014-08-04 CN CN201420435785.0U patent/CN204008864U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104897968A (en) * | 2015-05-14 | 2015-09-09 | 武汉市康达电气有限公司 | Method for testing impedance of earth screen based on phase-inversion incremental method |
| CN104897968B (en) * | 2015-05-14 | 2017-08-08 | 武汉市康达电气有限公司 | Mesh grounding impedance detecting method based on paraphase method of addition |
| CN105699784A (en) * | 2016-03-16 | 2016-06-22 | 国家电网公司 | Device for measuring grounding grid resistance by using voltage superposition method |
| CN108767984A (en) * | 2018-06-06 | 2018-11-06 | 中国铁路设计集团有限公司 | A kind of traction institute earth mat intelligent monitoring device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104931863B (en) | Synchronous generator for cable local discharge test | |
| CN203572883U (en) | Novel intelligent frequency-conversion large-current grounding impedance measuring instrument | |
| CN203299282U (en) | Grounding impedance tester | |
| CN205038273U (en) | Measurement device for earthing device power frequency and impact characteristic parameter | |
| CN204008864U (en) | Power-frequency earthing impedance instrument | |
| CN103176066A (en) | Digitization power quality monitoring device | |
| CN102788902B (en) | High-voltage transmission line power frequency parameter actual measuring device capable of resisting against high-induced voltage interference | |
| CN106707075A (en) | Online electric energy quality monitoring system based on ARM and FPGA | |
| CN103964312A (en) | Energy efficiency testing device and method for electric hoist | |
| CN203337792U (en) | Motor type test system | |
| CN206945841U (en) | The detection means of harmonic-eliminating resistor | |
| CN202351329U (en) | Constant current different frequency voltage limiting type anti-interference ground grid resistance test system | |
| CN205176195U (en) | Insulating status monitoring device of cable jacket | |
| CN204330849U (en) | A kind of Multi-function experimental virtual instrument | |
| CN204044261U (en) | A kind of electrical network resistance characteristic test device frequently | |
| CN203672976U (en) | Pilot frequency method ground resistor measuring device | |
| CN203981796U (en) | The transmission line power frequency parameter test instrument that the anti-high induction voltage of electronic type disturbs | |
| CN201765274U (en) | Energy-saving rate tester | |
| CN110007146A (en) | A kind of resonance point detecting method based on voltage and current harmonic phase | |
| CN106018989A (en) | Electric power quality metering collection analyzer | |
| CN203930041U (en) | Multifunctional electric energy meter is calibration device just | |
| CN109933099A (en) | Uranium enrichment gas centrifuge speed probe output signal processing device | |
| CN204008885U (en) | A kind of electronic type is with many back transmission lines of tower power frequency parameter test instrument | |
| CN203745631U (en) | Verifying system for on-line monitoring device of lightning arrester | |
| CN202870169U (en) | Anti-high induced voltage interference actual measurement device for power frequency parameters of high voltage transmission line |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141210 Termination date: 20170804 |