CN201392732Y - Charged measuring and installing device of transformer core grounding resistance - Google Patents
Charged measuring and installing device of transformer core grounding resistance Download PDFInfo
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- CN201392732Y CN201392732Y CN200920005799U CN200920005799U CN201392732Y CN 201392732 Y CN201392732 Y CN 201392732Y CN 200920005799 U CN200920005799 U CN 200920005799U CN 200920005799 U CN200920005799 U CN 200920005799U CN 201392732 Y CN201392732 Y CN 201392732Y
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Abstract
The utility model relates to a charged measuring and installing device of a transformer core grounding resistance. The grounding current of a running transformer core is limited and the charged fault elimination of the multipoint grounding faults of an electric transformer installation core is realized by choosing the most reasonable series resistance and installing the series resistance on line. The measuring and installing device comprises a short circuit switching unit, a demountable voltage testing plug-in card, a current testing plug-in card and a variable resistance plug-in card. The voltage testing plug-in card is connected between the terminal of the transformer core and the ground. The current testing plug-in card and the variable resistance plug-in card are connected in series and are then connected with the voltage testing plug-in card in parallel. The short circuit switching unit is connected with the two ends of the voltage testing plug-in card in parallel so that the short circuit between the terminal of the transformer core and the ground and the switching of the short circuit between the terminal of the transformer core and the variable resistance plug-in card are realized. The utility model can connect the grounding resistance with the grounding lead of the core in series on line and choose the resistance of the series resistance accurately so that the grounding current of the core reaches the required value.
Description
Technical field
The utility model relates to a kind of transformer core earth resistance live line measurement erecting device, by choosing the most reasonably series resistance and charged installation, limit transformer core earth current in service, realize that power transformer is installed multipoint earthing fault unshakable in one's determination charged disappear scarce.
Background technology
Along with development and national economy, more and more higher to the requirement of electric power system reliability service, power transformer is the hinge equipment of electric power system, and its reliability of operation is directly connected to the safety and stablization of electric power system.To the statistical results show of physical fault, the fault ratio that the iron core problem causes accounts for the 3rd of transformer ' s type fault, and the transformer core fault overwhelming majority in service is a multipoint earthing fault unshakable in one's determination.Multipoint earthing is as taking place in transformer core in service, forms the closed-loop path between earth point and iron core and produces circulation, produces bigger electric current in iron core, can reach tens amperes sometimes, causes the iron core partial short-circuit overheated on the one hand, iron core localized burn when serious; On the other hand, because the multipoint earthing of iron core produces circulation, cause the transformer part overheated, also may produce discharge property fault, safe operation constitutes a latent danger to transformer.
Transformer core multipoint earthing fault Diagnosis Method has three kinds, and the one, utilize transformer core to draw grounding sleeve outward, whether have electric current to occur on the earth connection, just often answer no current or electric current very little with pincerlike meter if measuring; The 2nd, transformer can directly be measured the insulation resistance of its iron core when having a power failure, if insulation resistance is zero or compared difference with last time and can determine to exist the iron core fault temporarily when very big; The 3rd, the gas-chromatography diagnostic method by measurement and the analysis to all gases component in the transformer insulation oil, thereby infers whether transformer core exists the multipoint earthing fault.
It mainly is have a power failure back employing capacitor charging/discharging method or low-voltage alternating-current ballistic method that the transformer that multipoint earthing fault unshakable in one's determination takes place is handled, and metal dust or the metal impurities that can eliminate in the oil are deposited in the impermanency ground connection that oil tank of transformer bottom formation " bridge joint " causes; Overhaul will be effective method to the permanent earth fault pendant-core examination.Can adopt the series resistance method when not possessing the suspended core condition again in that electric discharge is invalid, specific practice is to draw suitable resistance of serial connection on the earth connection outside iron core, increase the circulation resistance in circuit to reach the purpose that reduces iron core grounding current, thereby prevent local overheating unshakable in one's determination, alleviate the harm that multipoint earthing unshakable in one's determination brings.
In view of the method that seals in current-limiting resistance between iron core lead-in wire and ground can better limit the iron core grounding electric current, in electric power system, be used widely at present.Choosing of resistance value is the core technology of this method, and resistance value is chosen the too small restriction function of current that do not have, and resistance is excessive then can raise current potential unshakable in one's determination the possibility of quickening development of defects.The technical staff often by virtue of experience estimates the shortage accuracy at different capabilities and type transformer at present, needs repeatedly repetition test to determine resistance.
The processing that after multipoint earthing fault unshakable in one's determination occurring, often can not in time have a power failure of voltage levels high-power transformer in the system, so the transformer in the important places such as load-center substation of especially big load is charged judgement earthing type and handle multipoint earthing fault unshakable in one's determination and have very important significance.
The utility model content
The utility model is in order to solve the problem of choosing of series resistor resistance in the power transformer iron core multipoint earthing defective process, a kind of transformer core earth resistance live line measurement erecting device is provided, the accurate iron core grounding characteristic of measuring under the transformer normal operation can not influenced, choose series impedance accurately, and be with the online installation core earth resistance electricity of can realizing not having a power failure to install, make transformer core earth current in service reach ideal value.
The technical scheme in the invention for solving the technical problem is: a kind of transformer core earth resistance live line measurement erecting device, comprise short circuit switch unit and removable voltage tester plug-in unit, the testing current plug-in unit, with the variable resistor plug-in unit, described voltage tester plug-in unit is connected between transformer core terminals and the ground end, described testing current plug-in unit and variable resistor plug-in unit series connection back are in parallel with described voltage tester plug-in unit, described short circuit switch unit also is connected in parallel on described voltage tester plug-in unit two ends, realize short circuit between transformer core terminals and ground end, and the switching of short circuit between transformer core terminals and variable resistor plug-in unit.
Described short circuit switch unit can adopt single-pole double-throw switch (SPDT), and common port links to each other with described transformer core terminals, and the end in two end of converts is connected describedly to be held, and end is connected between described testing current plug-in unit and the variable resistor plug-in unit.
Described short circuit switch unit can comprise short switch and insert switch, and described short switch is connected in parallel between transformer core terminals and the ground end, described access switch be connected in parallel on after a short-circuit resistance connect transformer core terminals and hold between.
The utility model is by removable voltage tester plug-in unit, testing current plug-in unit and variable resistor plug-in unit, live line measurement power transformer iron core grounding characteristics, the online earth resistance that carries out seals in the iron core grounding lead-in wire, thereby reduces because the iron core grounding current value that multipoint earthing unshakable in one's determination causes.Can comparatively accurately choose the resistance of series resistance by the utility model, make the iron core grounding electric current reach required value.
Description of drawings
Fig. 1 is the schematic diagram of the utility model embodiment one;
Fig. 2 is a transformer core grounding characteristics curve synoptic diagram;
Fig. 3 is the schematic diagram of the utility model embodiment two.
Embodiment
Embodiment one: as shown in fig. 1, be a kind of preferred embodiment of the present utility model, comprise short circuit switch unit and removable voltage tester plug-in unit, the testing current plug-in unit, with the variable resistor plug-in unit, described voltage tester plug-in unit is connected between transformer core terminals and the ground end, described testing current plug-in unit and variable resistor plug-in unit series connection back are in parallel with described voltage tester plug-in unit, described short circuit switch unit adopts single-pole double-throw switch (SPDT), common port c links to each other with described transformer core terminals, b end in two end of converts is connected describedly to be held, and a end is connected between described testing current plug-in unit and the variable resistor plug-in unit.
Based on said structure, use operating process of the present utility model as follows:
1, measures grounding characteristics
Change by the resistance simulation iron core grounding series resistance that changes the variable resistor plug-in unit, thereby measure relevant voltage, current value draws the iron core grounding characteristic.
The variable resistor plug-in unit is adjusted to the resistance minimum value, the short circuit switch unit is drawn back, the ascending resistance value that changes the variable resistor plug-in unit gradually, and the current values that obtains of the voltage value surveyed of recording voltage probe card and testing current plug-in unit.After the off-test variable resistor plug-in unit is transferred to zero position, with b, the c end short circuit closure of diverter switch, recover the earthing mode of iron core grounding lead-in wire, test finishes.Experiment process should carry out in strict accordance with above operating procedure, should closed immediately diverter switch as unusual indication occurring in the voltage and current test process.The testing current plug-in unit can be surveyed current requirements greater than the iron core grounding electric current, and variable resistor plug-in unit thermal capacity should satisfy current requirements.
2, resistance value is chosen
1) iron core grounding characteristic curve protract
By testing the voltage U of being obtained
iAnd electric current I
iValue is drawn the iron core grounding performance diagram, and as shown in Figure 2, specific practice is to measurement data (U
i, I
i) (i=0,1 ..., m) use principle of least square method, ask to make error delta
i(i=0,1 ..., quadratic sum minimum m), promptly
Carry out curve fitting, thereby obtain comparatively real iron core grounding characteristic curve.
2) resistance value is chosen
According to State Grid Corporation of China's transformer service regulations requirement, determine the required numerical value I that reaches of iron core grounding current value
i, determine corresponding voltage value U by the iron core grounding characteristic curve
i, be calculated as follows out required resistance value R
i
3, the installation series resistance that do not have a power failure
Select step by above-mentioned resistance value, can measure the numerical value of the transformer core earth resistance that satisfies service requirement, the variable resistor plug-in unit is replaced by the required resistance that is suitable for long-term work, diverter switch is drawn back, observe voltage, electric current and resistance readings; A, c with diverter switch after affirmation resistance is working properly hold closure, remove voltage tester plug-in unit and testing current plug-in unit, realize resistance being sealed in the transformer core grounded circuit, promptly charged installation transformer core earth resistance.。The resistance that is inserted must possess greater thermal stability and possess safeguard procedures, prevents to damage to cause the transformer fe row to suspend.
Embodiment two: as shown in Figure 3, be another kind of preferred embodiment of the present utility model, comprise short circuit switch unit and removable voltage tester plug-in unit, the testing current plug-in unit, with the variable resistor plug-in unit, described voltage tester plug-in unit 7 is connected between transformer core terminals 1 and the ground end, described testing current plug-in unit 6 and variable resistor plug-in unit 5 series connection backs and described voltage tester plug-in unit 7 are in parallel, two switches of described short circuit switch unit, one is the short switch 8 that is connected in parallel between transformer core terminals and the ground end, another for be connected in parallel on transformer core terminals 1 and the ground access switch 2 between holding after a short-circuit resistance 4 connect.
Adopt the course of work and the embodiment one of present embodiment basic identical, when the test grounding characteristics, to insert switch 2 disconnections and short switch 8 disconnects, the ascending resistance value that changes the variable resistor plug-in unit gradually, and the current values that obtains of the voltage value surveyed of recording voltage probe card and testing current plug-in unit, obtain the iron core grounding characteristic curve, after having chosen rational resistance value, the short-circuit resistance 4 of matters long-term work is inserted, remove voltage tester plug-in unit 7 again, testing current plug-in unit 6 and variable resistor plug-in unit 5, to insert switch 2 closures at last, short switch 8 will be disconnected, also can realize charged installation transformer core earth resistance.
More than transformer core earth resistance live line measurement erecting device provided by the utility model is described in detail, used specific case herein principle of the present utility model and execution mode are set forth, the explanation of above embodiment just is used for helping to understand method of the present utility model and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present utility model, the part that all can change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model.
Claims (3)
1. transformer core earth resistance live line measurement erecting device, it is characterized in that: comprise short circuit switch unit and removable voltage tester plug-in unit, the testing current plug-in unit, with the variable resistor plug-in unit, described voltage tester plug-in unit is connected between transformer core terminals and the ground end, described testing current plug-in unit and variable resistor plug-in unit series connection back are in parallel with described voltage tester plug-in unit, described short circuit switch unit also is connected in parallel on described voltage tester plug-in unit two ends, realize short circuit between transformer core terminals and ground end, and the switching of short circuit between transformer core terminals and variable resistor plug-in unit.
2. transformer core earth resistance live line measurement erecting device according to claim 1, it is characterized in that: described short circuit switch unit adopts single-pole double-throw switch (SPDT), common port links to each other with described transformer core terminals, end in two end of converts is connected describedly to be held, and end is connected between described testing current plug-in unit and the variable resistor plug-in unit.
3. transformer core earth resistance live line measurement erecting device according to claim 1, it is characterized in that: described short circuit switch unit comprises short switch and inserts switch, described short switch is connected in parallel between transformer core terminals and the ground end, described access switch be connected in parallel on after a short-circuit resistance connect transformer core terminals and hold between.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920005799U CN201392732Y (en) | 2009-03-16 | 2009-03-16 | Charged measuring and installing device of transformer core grounding resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920005799U CN201392732Y (en) | 2009-03-16 | 2009-03-16 | Charged measuring and installing device of transformer core grounding resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201392732Y true CN201392732Y (en) | 2010-01-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200920005799U Expired - Lifetime CN201392732Y (en) | 2009-03-16 | 2009-03-16 | Charged measuring and installing device of transformer core grounding resistance |
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| Country | Link |
|---|---|
| CN (1) | CN201392732Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101572181B (en) * | 2009-03-16 | 2012-10-03 | 国家电网公司 | Transformer core earth resistance live line measurement installing device and method therefor |
-
2009
- 2009-03-16 CN CN200920005799U patent/CN201392732Y/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101572181B (en) * | 2009-03-16 | 2012-10-03 | 国家电网公司 | Transformer core earth resistance live line measurement installing device and method therefor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100127 Effective date of abandoning: 20090316 |