CN202678952U - Transformer neutral point DC current suppression device adopting series capacitor method - Google Patents
Transformer neutral point DC current suppression device adopting series capacitor method Download PDFInfo
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- CN202678952U CN202678952U CN 201120563915 CN201120563915U CN202678952U CN 202678952 U CN202678952 U CN 202678952U CN 201120563915 CN201120563915 CN 201120563915 CN 201120563915 U CN201120563915 U CN 201120563915U CN 202678952 U CN202678952 U CN 202678952U
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- neutral point
- capacitor
- transformer neutral
- current
- transformer
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Abstract
The utility model discloses a transformer neutral point DC current suppression device adopting a series capacitor method. A scheme of serially connecting a capacitor at a transformer neutral point to block a DC current is adopted, the capacitor is parallelly connected with a fast bypass system consisting of a fast switch, a rectifier bridge, a high-power thyristor, an overvoltage triggering unit, a fast tripping circuit the like, and a monitoring unit is additionally arranged.
Description
Affiliated technical field
The utility model relates to the transformer power transmitting device, especially the transformer neutral point DC current restraining device of series-capacitor.
Background technology
Earth current affects operating transformer under the elimination direct current transportation single-stage the earth operational mode, mainly contains neutral point series connected resistance, neutral point series-capacitor and neutral point reverse current injection method.Present research is thought, can only weaken the direct current of inflow transformer neutral point at transformer neutral point series connection small resistor, and have when electric network composition changes the problem that resistance need to be readjusted; The current injection method utilization is newly established " the second earth point " outside the transformer neutral point and is injected reverse current and eliminate direct current to the impact of transformer, but using this Injection Current only has about 20% and can flow into transformer neutral point to be administered, other 80% electric current whereabouts unknown, and newly establishing " the second earth point " needs again expropriation of land, and construction investment is large.
The utility model content
Earth current affects operating transformer under the direct current transportation single-stage the earth operational mode in order to eliminate, the utility model provides a kind of transformer neutral point DC current restraining device of series-capacitor, this device is not only in the electric network fault situation, guaranteed the safety of transformer neutral point, and can be widely used in electric power system and increase monitoring unit.
The technical scheme in the invention for solving the technical problem is: this device is made of block capacitor and the quick bypath system of overvoltage, the quick bypass loop of overvoltage is comprised of several parts such as high-speed switch, rectifier bridge, thyristor, overvoltage trigger element, rapid-releasing loops, employing suppresses direct current at transformer neutral point access capacitor, utilizes the conversion that realizes direct ground connection running status and capacity earth running status with the high-speed switch of Parallel-connected Capacitor.
The quick bypass loop of overvoltage adopts at transformer neutral point access capacitor and suppresses direct current, utilizes the conversion that realizes direct ground connection running status and capacity earth running status with the high-speed switch of Parallel-connected Capacitor.
Monitoring unit comprises 2 parts of device side controller and monitoring backstage, control room.
The beneficial effects of the utility model are: series-capacitor have principle simple, every straight successful, do not need to readjust the advantage such as protective relaying device definite value, have preferably economy and engineering practicability.Can not only the establishment transformer neutral point DC current, and can be widely used in electric power system, simple in structure.
Description of drawings
Below in conjunction with drawings and Examples the utility model is further specified.
Fig. 1 is the transformer neutral point DC current restraining device schematic diagram of series-capacitor.
Fig. 2 is NCBD application system figure.
Among the figure 1, capacitor 2, overvoltage trigger power supply 3, thyristor 4, rectifier bridge 5, high-speed switch 6, transformer 7, suppress transformer neutral point 8, master control remote monitoring terminal machine 9, main control room alarm window signal.
Embodiment
The transformer neutral point DC current restraining device of series-capacitor by: 1, capacitor 2, overvoltage trigger power supply 3, thyristor 4, rectifier bridge 5, high-speed switch and form.
The NCBD application system by: 6, transformer 7, suppress transformer neutral point 8, master control remote monitoring terminal machine 9, main control room alarm window signal and form.
One, the operation principle of CBD and operational mode
1.1NCBD operation principle
Device adopts at transformer (6) neutral point access capacitor (1) and suppresses direct current, utilizes the high-speed switch (5) in parallel with capacitor (1) to realize the conversion of direct ground connection running status and capacity earth running status.Device is made of block capacitor (1) and the quick bypath system of overvoltage, the quick bypass loop of overvoltage is comprised of 5 parts such as high-speed switch (5), rectifier bridge (4), thyristor (3), overvoltage trigger element (2), rapid-releasing loops, and principle of device as shown in Figure 1.It is 20kA, 1s that device can bear maximum capacity of short circuit, industrial frequency AC capacitive reactance＜1.2 Ω, bypass operate time＜20 μ s.
1.2 operational mode
This device has 2 kinds of operational modes, i.e. neutral-point solid ground operation and the operation of neutral point capacity earth.
Among Fig. 3: when high-speed switch (5) disconnects, install and be neutral point capacity earth operational mode; When high-speed switch (5) is closed, installs and be the neutral-point solid ground operational mode.
1.3 bypath system
If only series capacitor (1) at transformer (6) neutral point with isolated DC, consider in the electric network fault situation that neutral point can overvoltage, the capacitor value of electric capacity must be selected very littlely, and withstand voltage must be very high, under present power capacitor (1) manufacture level, must adopt multiple unit capacitor (1) connection in series-parallel, increased like this volume of equipment, improved the cost of equipment, therefore, series capacitance does not have engineering feasibility, must adopt capacitor (1) to add the design of bypath system.
Under the capacity earth running status, when AC system generation three-phase imbalance fault, might produce at capacitor (1) two ends high voltage, this timer adopts 3 grades of relay-type bypass schemes: the 1st grade is thyristor (3), fault current in the electric network fault situation will cause neutral point voltage to raise, and thyristor (3) conducting makes neutral point enter fast direct ground state; The 2nd grade is high-speed switch (5) bypass by thyristor (3) current drives, because the restriction of thyristor (3) afterflow ability, 20ms occurs in short circuit must be closed with interior high-speed switch (5), forms the direct ground connection of metallicity of neutral point; 3rd level is the reserve bypass protection that metal oxide arrester (metal oxide varistor, MOV) etc. forms.
Two, NCBD monitoring unit
In using at the scene, because the direct current system operational mode has uncertainty, need a kind of intelligent equipment, when direct current system is normally moved, excision capacitor (1), transformer (6) neutral-point solid ground operation; Larger at neutral point direct current, when affecting transformer (6) stable operation, drop into capacitor (1), transformer (6) neutral point is by the operation of capacitor (1) ground connection; When electric power system fault, the bypath system action makes transformer (6) neutral-point solid ground, to guarantee the safety of neutral point and capacitor (1).NCBD equipment also must can guarantee the safe operation of transformer (6) like this along with automatic switching is carried out in the variation of direct current, has alleviated again field operator's workload.For satisfying above-mentioned requirements, Pa river No. 1 main transformer NCBD device has increased monitoring unit on the basis of primary system, and monitoring unit comprises 2 parts of device side controller and monitoring backstage, control room.NCBD the field system configuration as shown in Figure 2.The major function that monitoring unit is finished is as follows:
1) conversion of operational mode.
Under the neutral-point solid ground operational mode, when neutral point current surpasses the setting thresholding, if device is in automatic control mode, monitoring unit can send high-speed switch (5) tripping signal makes device enter neutral point capacity earth operational mode, and automatically drops into cue to main control room terminal issue device; If device is in manual control model, only send overcurrent alarm signal (central alarm signal flicker) to the main control room terminal, remind the operations staff manually device to be switched to neutral point capacity earth operational mode.Under neutral point capacity earth operational mode, when block capacitor (1) both end voltage is lower than the setting thresholding, if device is in automatic control mode, supervisory control system is sent high-speed switch (5) closure signal makes device enter the neutral-point solid ground operational mode, and to the cue of main control room terminal issue device automatic earthing; If device is in manual control model, only send low pressure warning signal (central alarm signal flicker) to the main control room terminal, remind the operations staff can manually device be switched to the neutral-point solid ground operational mode.
2) the online reliability test of device bypath system.
For improving the reliability of device bypath system, device is provided with automatic test loop, and the test loop does not seal in any element in the device main devices loops such as capacitor (1), high-speed switch (5), both guarantee the miscellaneous function of test loop, and can not produce any impact to the reliability of device again.Maybe when device switches to the capacity earth mode by the neutral-point solid ground mode, device firing test loop drives the closed mechanism of high-speed switch (5), rectifier bridge (4) conduction, capacitor (1) to thyristor (3) and discharges and recharges and test after device is finished primary fault current bypass process.
Claims (3)
1. the transformer neutral point DC current restraining device of series-capacitor, it is characterized in that: adopt the scheme at transformer neutral point series capacitor blocking-up direct current, and Parallel-connected Capacitor the quick bypath system that formed by high-speed switch, rectifier bridge, high-power thyristor, overvoltage trigger element, rapid-releasing loop and increased monitoring unit.
2. the transformer neutral point DC current restraining device of series-capacitor according to claim 1, it is characterized in that: the quick bypass loop of overvoltage adopts at transformer neutral point access capacitor and suppresses direct current, utilizes the conversion that realizes direct ground connection running status and capacity earth running status with the high-speed switch of Parallel-connected Capacitor.
3. the transformer neutral point DC current restraining device of series-capacitor according to claim 1 is characterized in that: monitoring unit comprises 2 parts of device side controller and monitoring backstage, control room.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120563915 CN202678952U (en) | 2011-12-30 | 2011-12-30 | Transformer neutral point DC current suppression device adopting series capacitor method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120563915 CN202678952U (en) | 2011-12-30 | 2011-12-30 | Transformer neutral point DC current suppression device adopting series capacitor method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202678952U true CN202678952U (en) | 2013-01-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201120563915 Expired - Fee Related CN202678952U (en) | 2011-12-30 | 2011-12-30 | Transformer neutral point DC current suppression device adopting series capacitor method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202678952U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683194A (en) * | 2013-12-17 | 2014-03-26 | 国家电网公司 | Transformer neutral point direct current suppression device |
| CN105655998A (en) * | 2016-03-31 | 2016-06-08 | 国网天津市电力公司 | Low-voltage side neutral point FACTS (flexible alternating current transmission systems) grounding device of 110kV transformer |
| CN106711945A (en) * | 2016-10-19 | 2017-05-24 | 许继集团有限公司 | Direct current blocking equipment with fault diagnosis function and diagnosis method |
-
2011
- 2011-12-30 CN CN 201120563915 patent/CN202678952U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683194A (en) * | 2013-12-17 | 2014-03-26 | 国家电网公司 | Transformer neutral point direct current suppression device |
| CN105655998A (en) * | 2016-03-31 | 2016-06-08 | 国网天津市电力公司 | Low-voltage side neutral point FACTS (flexible alternating current transmission systems) grounding device of 110kV transformer |
| CN106711945A (en) * | 2016-10-19 | 2017-05-24 | 许继集团有限公司 | Direct current blocking equipment with fault diagnosis function and diagnosis method |
| CN106711945B (en) * | 2016-10-19 | 2018-10-19 | 许继集团有限公司 | A kind of blocking device and diagnostic method of tape jam diagnostic function |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130116 Termination date: 20131230 |