CN105048431A - Suppression device for DC biasing current of transformer - Google Patents
Suppression device for DC biasing current of transformer Download PDFInfo
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- CN105048431A CN105048431A CN201510485907.6A CN201510485907A CN105048431A CN 105048431 A CN105048431 A CN 105048431A CN 201510485907 A CN201510485907 A CN 201510485907A CN 105048431 A CN105048431 A CN 105048431A
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Abstract
The invention discloses a suppression device for DC biasing current of a transformer. The suppression device comprises a neutral point access port, a ground port, a positive temperature coefficient thermistor, a capacitor and a controlled clearance element, wherein the positive temperature coefficient thermistor is used for suppressing the DC biasing current when the DC earth current is increased; the capacitor is used for providing an access for a non-DC current component of a neutral point of the transformer when the positive temperature coefficient thermistor suppresses the DC biasing current, wherein the positive temperature coefficient thermistor is connected between the neutral point access port and the ground port; the capacitor is connected between the neutral point access port and the ground port; and the controlled clearance element is connected between the neutral point access port and the ground port. By adopting the embodiment of the invention, the influence of the DC biasing current on the transformer can be eliminated without affecting line protection of a power grid.
Description
Technical field
The present invention relates to electric power network technique field, particularly relate to a kind of DC magnetic bias current restraining device of transformer.
Background technology
In recent years, with rapid economic development, energy demand increases, and remote, high-capacity direct current power transmission engineering develops rapidly.It is carry out operation between loop and bipolar balance mode to switch with the earth that DC line in AC system usually needs at one pole.When one pole take the earth as loop operation, huge direct current is formed loop with the earth, and can form potential difference between AC Substation, direct current will flow through Transformer Winding by transformer central point and transmission line, make transformer outlet bias phenomenon.The zone of saturation that neutral-point solid ground transformer in AC network is operated in excitation region can cause that its vibration is violent, the acute liter of noise, the overheated and total abnormal rate of ac grid voltage significantly raise, and can cause transformer damage time serious.
Direct current grounding pole earth current has following features to substation transformer impact: the time uncertain (fault or occur between turn(a)round), action time is short, earth current amplitude is large, positive-negative polarity is uncertain and large on transformer impact.At present, the method and apparatus of existing multiple suppression transformer DC magnetic bias current, mainly contains electric capacity and seals in the method and apparatus such as small resistor, reverse dc, potential compensation every straight, neutral point.And the technical scheme nearest with the present invention is neutral point seals in small resistor, it is the small resistor of several ohm that the method seals in a resistance between central point and earth mat, and the direct current that neutral point is flowed into obviously reduces, and reaches acceptable degree in engineering.But neutral point termination can have an impact to system zero order parameter, thus has influence on adjusting of zero-sequenceprotection, and cannot completely cancellation DC magnetic bias current on the impact of transformer.
Summary of the invention
The embodiment of the present invention proposes a kind of DC magnetic bias current restraining device of voltage device, can eliminate the impact of DC magnetic bias current on transformer, and not affect the route protection of electrical network.
The embodiment of the present invention provides a kind of DC magnetic bias current restraining device of transformer, comprising: neutral point access interface, grounding ports, semistor, electric capacity and control gap element;
Described semistor is used for when direct current earth current increases, and suppresses DC magnetic bias current;
Described electric capacity is used for when described semistor suppresses described DC magnetic bias current, for the neutral point non-direct current component of described transformer provides path;
Wherein, described semistor is connected between described neutral point access interface and described grounding ports;
Described electric capacity is connected between described neutral point access interface and described grounding ports;
Described control gap element is connected between described neutral point access interface and described grounding ports.
Further, described semistor is non-linear positive temperature coefficient resistance.
Further, described control gap element is the control gap element of ball-type shape.
Further, this restraining device also comprises: voltage sensor and current sensor;
Described voltage sensor and described semistor are connected in parallel;
Described current sensor is connected between described semistor and described grounding ports.
Further, this restraining device also comprises: watch-dog,
Described watch-dog is connected with described voltage sensor, current sensor respectively.
Visible, implement the embodiment of the present invention, there is following beneficial effect:
Embodiments provide a kind of DC magnetic bias current restraining device of transformer, comprising: neutral point access interface, grounding ports, semistor, electric capacity and control gap element.Wherein, semistor, electric capacity and control gap element parallel with one another after be linked between neutral point access interface and grounding ports.When working properly, the electric current flowing through transformer neutral point is very little, and the resistance of semistor is less, and neutral point current can flow through semistor access the earth.When DC transmission engineering is run for circuit type with one pole the earth, direct current earth current increases, the temperature of semistor raises and causes resistance to increase, DC magnetic bias current is made to be difficult to pass through from semistor and electric capacity, by transformer neutral point current limit at reduced levels, thus reduce the earth current flowing into AC system.Access the resistance of several ohm of sizes at neutral point compared to prior art; the thermistor of technical solution of the present invention in normal operation resistance much smaller than 1 ohm; avoid the impact of zero-sequenceprotection parameter; and the resistance of this device can increase with the increase of electric current, the effect of DC magnetic bias current to transformer substantially can be eliminated.
Further; if when transformer normally works there is AC system short trouble in (without the impact of direct current earth current); short trouble zero-sequence current will flow through semistor and electric capacity; because semistor resistance is less; be equivalent to AC system ground connection, do not affect circuit Control protection definite value.Along with flowing continuously through of short trouble zero-sequence current, semistor causes temperature to rise with heating power increase, and resistance sharply increases, thus reaches the effect of restriction short circuit zero-sequence current.If DC transmission engineering with one pole the earth for there is AC system short trouble when circuit type runs, due to direct current earth current the resistance affecting semistor very greatly, major part flows through from electric capacity by short-circuit current.But now transformer neutral point is equivalent to, through the less capacity earth of impedance, to have an impact to route protection.
Further, there is not power electronics equal controller in this device, served the function of input, excision electric capacity by the self-characteristic of semistor, reduces to have lacked the equipment caused because of power electronic equipment fault and be failure to actuate or misoperation.And this device has that structure is simple, volume is very little, easy for installation, fund input is less, do not change earthing mode when transformer normally runs, on route protection without advantages such as impacts, be beneficial in engineering and apply.
Further, this device also comprises watch-dog, can power on and compress into row monitoring, and above-mentioned data are sent to grid operating monitoring department in real time transformer DC magnetic bias current size, this device action situation, nonlinear resistance.Grid operating monitoring department can grasp the ruuning situation of transformer and this device in real time, realizes remote monitoring.
Accompanying drawing explanation
The structural representation of a kind of embodiment of the DC magnetic bias current restraining device of Fig. 1 transformer provided by the invention;
Fig. 2 is the structural representation of the another kind of embodiment of the DC magnetic bias current restraining device of transformer provided by the invention;
Fig. 3 is the structural representation of another embodiment of the DC magnetic bias current restraining device of transformer provided by the invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
See Fig. 1, it is the structural representation of a kind of embodiment of the DC magnetic bias current restraining device of transformer provided by the invention.As shown in Figure 1, this DC magnetic bias current restraining device comprises: neutral point access interface 101, grounding ports 102, semistor 103, electric capacity 104 and control gap element 105.
Semistor 103, for when direct current earth current increases, suppresses DC magnetic bias current.
Electric capacity 104 for when semistor 103 suppresses DC magnetic bias current, for the neutral point non-direct current component of transformer provides path.In addition, when circuit is short-circuited fault, electric capacity 104 also can be semistor 103 and shares partial short circuit electric current.
In the present embodiment, neutral point access interface 101 is connected with the neutral point of external transformer.Grounding ports 102 is connected with signal ground.
In the present embodiment, semistor 103 is connected between neutral point access interface 101 and grounding ports 102.Electric capacity connects 104 and is connected between neutral point access interface 101 and grounding ports 102.Control gap element 105 is connected between neutral point access interface 101 and grounding ports 102.
In the present embodiment, semistor 103 is non-linear positive temperature coefficient resistance.Non-linear positive temperature system thermistor is when temperature is close with room temperature, and resistance very little (much smaller than 1 ohm), when the temperature increases, resistance can sharply raise.
In the present embodiment, control gap element 105 is the control gap element of ball-type shape, for when short circuit current effect, the overvoltage at semistor and electric capacity two ends is larger, exceed the operating valve value that control gap element is preset, disruptive discharge is formed discharge path by ball gap, reduces transformer neutral point overvoltage.This control gap element comprises the electrode of two ball-type shapes, and the distance between two ball electrodes can adjust as required, to adjust this action threshold value.
The operation principle of this device is specific as follows: neutral point access interface 101 is connected with the neutral point of transformer in AC Substation, grounding ports 102 ground connection.When transformer normally works (without the impact of direct current earth current), the electric current flowing through transformer neutral point is less, and the temperature of semistor is close with room temperature, and resistance is very little, be equivalent to neutral ground, do not affect transformer and normally work.When DC transmission engineering is run for circuit type with one pole the earth, neutral point by transformer is flowed into AC Substation by direct current earth current, now, the electric current flowing through positive temperature thermistor is larger, semistor causes temperature to rise due to heating power increase, resistance can sharply increase, thus restriction DC magnetic bias current is passed through from this device, by transformer neutral point current limit in lower level, greatly reduce the earth current flowing into AC Substation, avoid the excessive harmful effect caused of direct current earth current.
One as the present embodiment is illustrated, and is the structural representation of the another kind of embodiment of the DC magnetic bias current restraining device of transformer provided by the invention see Fig. 2, Fig. 2.The difference of Fig. 2 and Fig. 1 is, this device also comprises: voltage sensor 206, current sensor 207 and watch-dog 208.Voltage sensor 206 and semistor 103 are connected in parallel.Current sensor 207 is connected between semistor 103 and grounding ports 102.Watch-dog 208 is connected with voltage sensor 206, current sensor 207 respectively.Voltage sensor 206 is for measuring neutral point voltage, and current sensor 207 is for measuring neutral point current.Electric current, magnitude of voltage that watch-dog 208 is measured for monitoring voltage transducer 206 and current sensor 207, grasp equipment running status, and for by data upload to remote control center.
One as the present embodiment is illustrated, and is the structural representation of another embodiment of the DC magnetic bias current restraining device of transformer provided by the invention see Fig. 3, Fig. 3.As shown in Figure 3, this device comprises: semistor 301, electric capacity 302, spherical control gap element 303, voltage sensor PT, current sensor CT, digital monitor 304 and long distance control system 305.Wherein, semistor 301, electric capacity 302, spherical control gap element 303, voltage sensor PT connection parallel with one another, between the neutral point that semistor 301 is connected to transformer high-voltage winding and signal ground.Current sensor CT is connected between semistor 301 and signal ground.Digital monitor 304 be connected with voltage sensor PT, current sensor CT respectively.Long distance control system 305 is connected with digital monitor 304.
Therefore, embodiments provide a kind of DC magnetic bias current restraining device of transformer, comprising: neutral point access interface 101, grounding ports 102, semistor 103, electric capacity 104 and control gap element 105.Wherein, semistor 103, electric capacity 104 and control gap element 105 parallel with one another after be linked between neutral point access interface 101 and grounding ports 102.When working properly, the electric current flowing through transformer neutral point is very little, and the resistance of semistor 103 is less, and neutral point current can flow through semistor 103 and access the earth.When DC transmission engineering is run for circuit type with one pole the earth, direct current earth current increases, the temperature of semistor 103 raises and causes resistance to increase, DC magnetic bias current is made to be difficult to pass through from semistor 103 and electric capacity 104, by transformer neutral point current limit at reduced levels, thus reduce the earth current flowing into AC system.Access the resistance of several ohm of sizes at neutral point compared to prior art; the thermistor of technical solution of the present invention in normal operation resistance much smaller than 1 ohm; avoid the impact of zero-sequenceprotection parameter; and the resistance of this device can increase with the increase of electric current, the effect of DC magnetic bias current to transformer substantially can be eliminated.
Further; if when transformer normally works there is AC system short trouble in (without the impact of direct current earth current); short trouble zero-sequence current will flow through semistor and electric capacity; because semistor resistance is less; be equivalent to AC system ground connection, do not affect circuit Control protection definite value.Along with flowing continuously through of short trouble zero-sequence current, semistor causes temperature to rise with heating power increase, and resistance sharply increases, thus reaches the effect of restriction short circuit zero-sequence current.If DC transmission engineering with one pole the earth for there is AC system short trouble when circuit type runs, due to direct current earth current the resistance affecting semistor very greatly, major part flows through from electric capacity by short-circuit current.But now transformer neutral point is equivalent to, through the less capacity earth of impedance, to have an impact to route protection.
Further, there is not power electronics equal controller in this device, served the function of input, excision electric capacity by the self-characteristic of semistor, reduces to have lacked the equipment caused because of power electronic equipment fault and be failure to actuate or misoperation.And this device has that structure is simple, volume is very little, easy for installation, fund input is less, do not change earthing mode when transformer normally runs, on route protection without advantages such as impacts, be beneficial in engineering and apply.
Further, this device also comprises watch-dog, can power on and compress into row monitoring, and above-mentioned data are sent to grid operating monitoring department in real time transformer DC magnetic bias current size, this device action situation, nonlinear resistance.Grid operating monitoring department can grasp the ruuning situation of transformer and this device in real time, realizes remote monitoring.
The above is the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.
Claims (5)
1. a DC magnetic bias current restraining device for transformer, is characterized in that, comprising: neutral point access interface, grounding ports, semistor, electric capacity and control gap element;
Described semistor is used for when direct current earth current increases, and suppresses DC magnetic bias current;
Described electric capacity is used for when described semistor suppresses described DC magnetic bias current, for the neutral point non-direct current component of described transformer provides path;
Wherein, described semistor is connected between described neutral point access interface and described grounding ports;
Described electric capacity is connected between described neutral point access interface and described grounding ports;
Described control gap element is connected between described neutral point access interface and described grounding ports.
2. the DC magnetic bias current restraining device of transformer according to claim 1, is characterized in that, described semistor is non-linear positive temperature coefficient resistance.
3. the DC magnetic bias current restraining device of transformer according to claim 1, is characterized in that, described control gap element is the control gap element of ball-type shape.
4., according to the DC magnetic bias current restraining device of the arbitrary described transformer of claims 1 to 3, it is characterized in that, also comprise: voltage sensor and current sensor;
Described voltage sensor and described semistor are connected in parallel;
Described current sensor is connected between described semistor and described grounding ports.
5. the DC magnetic bias current restraining device of transformer according to claim 4, is characterized in that, also comprise: watch-dog,
Described watch-dog is connected with described voltage sensor, current sensor respectively.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510485907.6A CN105048431B (en) | 2015-08-10 | 2015-08-10 | A kind of DC magnetic bias current restraining device of transformer |
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| CN201510485907.6A CN105048431B (en) | 2015-08-10 | 2015-08-10 | A kind of DC magnetic bias current restraining device of transformer |
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| CN105048431A true CN105048431A (en) | 2015-11-11 |
| CN105048431B CN105048431B (en) | 2018-09-18 |
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Citations (6)
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| CN2907023Y (en) * | 2006-05-19 | 2007-05-30 | 南方电网技术研究中心 | Device for suppressing DC magnetic bias current in AC transformer |
| CN101931205A (en) * | 2010-08-19 | 2010-12-29 | 张致良 | Three-phase power supply network electromagnetic voltage transformer harmonic elimination protector |
| CN102709881A (en) * | 2012-03-15 | 2012-10-03 | 东北电力科学研究院有限公司 | Device utilizing adjustable resistance method to curb DC of neutral point of transformer |
| KR20130026691A (en) * | 2011-09-06 | 2013-03-14 | 한국전력공사 | Device and method for grounding the neutral |
| CN203631282U (en) * | 2013-12-19 | 2014-06-04 | 国家电网公司 | DC magnetic bias online monitoring and separating device of power transformer |
| CN204835520U (en) * | 2015-08-10 | 2015-12-02 | 中国南方电网有限责任公司电网技术研究中心 | Dc magnetic biasing electric current suppression device of transformer |
-
2015
- 2015-08-10 CN CN201510485907.6A patent/CN105048431B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2907023Y (en) * | 2006-05-19 | 2007-05-30 | 南方电网技术研究中心 | Device for suppressing DC magnetic bias current in AC transformer |
| CN101931205A (en) * | 2010-08-19 | 2010-12-29 | 张致良 | Three-phase power supply network electromagnetic voltage transformer harmonic elimination protector |
| KR20130026691A (en) * | 2011-09-06 | 2013-03-14 | 한국전력공사 | Device and method for grounding the neutral |
| CN102709881A (en) * | 2012-03-15 | 2012-10-03 | 东北电力科学研究院有限公司 | Device utilizing adjustable resistance method to curb DC of neutral point of transformer |
| CN203631282U (en) * | 2013-12-19 | 2014-06-04 | 国家电网公司 | DC magnetic bias online monitoring and separating device of power transformer |
| CN204835520U (en) * | 2015-08-10 | 2015-12-02 | 中国南方电网有限责任公司电网技术研究中心 | Dc magnetic biasing electric current suppression device of transformer |
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| CN105048431B (en) | 2018-09-18 |
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Effective date of registration: 20210519 Address after: 510670 3rd, 4th and 5th floors of building J1 and 3rd floor of building J3, No.11 Kexiang Road, Science City, Luogang District, Guangzhou City, Guangdong Province Patentee after: China Southern Power Grid Research Institute Co.,Ltd. Address before: Room 505-508, 4th and 5th floor, No.6 Huasui Road, Zhujiang New Town, Tianhe District, Guangzhou, Guangdong 510000 Patentee before: CSG POWER GRID TECHNOLOGY RESEARCH CENTER Patentee before: China Southern Power Grid Research Institute Co.,Ltd. |