CN103904633A - Overvoltage suppressing method for terminal box below transformer substation bus - Google Patents
Overvoltage suppressing method for terminal box below transformer substation bus Download PDFInfo
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- CN103904633A CN103904633A CN201410098837.4A CN201410098837A CN103904633A CN 103904633 A CN103904633 A CN 103904633A CN 201410098837 A CN201410098837 A CN 201410098837A CN 103904633 A CN103904633 A CN 103904633A
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Abstract
The invention discloses an overvoltage suppressing method for a terminal box below a transformer substation bus. The method includes the sequential steps that a surge protector is selected according to the maximum continuous working voltage Uc, a voltage protection level Up, the maximum discharge current Imax and response time, wherein the voltage protection level Up is smaller than an impulse withstand voltage value of protected equipment; the position for generating overvoltage in a secondary circuit of a transformer substation is determined, and the grounded form of a low-voltage distribution system is analyzed; the surge protector and the protected equipment are installed in parallel; when a disconnecting link is operated, the secondary circuit where the surge protector is already installed is measured through a oscilloscope to obtain waveforms and data, and feasibility and effectiveness for suppressing overvoltage of the secondary circuit by additionally installing the surge protector are proved. The method can effectively reduce occurrence probability of faults in the secondary circuit in the transformer substation.
Description
Technical field
The present invention relates to the security fields of transmitting electricity, particularly the method for a kind of substation bus bar below terminal box over-voltage suppression.
Background technology
Along with increasing sharply of China's economy and social fast development and need for electricity; China's power industry has entered the developing period of large electrical network, large unit, high voltage, high automation; Automatization Technology in Transformer Substation is wherein also day by day universal; the weak current equipment adopting in transformer station and electrical secondary system are more and more; as data acquisition system, communication system, control and relaying protection system etc., and because these secondary devices of Technical Economy are also more and more delegated in transformer station's high-voltage switch gear field.But, the electronic equipment being made up of very lagre scale integrated circuit (VLSIC) is subject to the impact of periphery electromagnetic environment, under the effect of electromagnetic interference signal, may there is the phenomenon of misoperation or device damage, and then have influence on the safe operation of electric power system, thereby power grid security is formed to serious threat.The transient electromagnetic field that thunderbolt, switching manipulation, system short-circuit fault etc. produce all can be produced and disturb multiple secondary device by secondary cable or power line.Therefore, in electric power system, the electromagnetic compatibility problem of transformer station becomes a key factor guaranteeing power system security reliability service.Meanwhile, the electromagnetic interference on secondary cable also becomes the main study subject of substation electromagnetic compatibility research.
In recent years, in carrying out 500kV bus switch operation, there is isolating switch arcing when dividing, closing in some 500kV transformer stations.At this moment bus below terminal box general supply air switch or other air switches can trip.After tripping operation, some transformer stations can closing by hand air switch (station, Ru Die ridge); Cannot overlap (as the 500kV station in Zhaoqing) having.Can closing by hand time, operating personnel directly have certain potential safety hazard in bus below; When manual operation is unsuccessful, the long-time arcing of switch meeting causes the accidents such as switch in parallel capacitor blast.
Current counter-measure just instructs in the time that arc is robbed in the tripping operation of terminal box air switch and how to operate, and does not fundamentally solve and avoid the problems referred to above.Therefore, proposing a kind of method, to go fundamentally to solve problems very urgent.
Summary of the invention
The shortcoming that the object of the invention is to overcome prior art, with not enough, provides the method for a kind of substation bus bar below terminal box over-voltage suppression, the step that comprises following order:
S1. the selection of surge protector
According to maximum Uc U
c, the horizontal U of voltage protection
p, maximum discharge current I
maxand the response time select surge protector, the wherein horizontal U of voltage protection
pwill be lower than the impulse withstand voltage value of protected equipment;
S2. the installation of surge protector
(1) determine that Substation secondary circuit produces superpotential position, and analyze the ground connection form of low-voltage distribution system;
(2) surge protector and protected equipment are installed in parallel;
S3. in the time of switch operation, the secondary circuit that installs surge protector is measured by oscilloscope, obtained waveform and data, prove to install additional surge protector to suppressing the superpotential feasibility of secondary circuit and validity.
Described maximum Uc U
c, for can be applied to continuously maximum a.c. voltage or the direct voltage at surge protector two ends in the temperature range of regulation, wherein maximum a.c. voltage refers to the effective value of maximum a.c. voltage.
Described maximum Uc U
c, in the time selecting surge protector, be divided into following situation:
(1) in TT system, U
c>=1.55U
o, wherein U
ofor the specified phase voltage of protected circuit;
(2) in TN system and TT system, U
c>=1.15U
o, wherein U
ofor the specified phase voltage of protected circuit;
(3) in IT system and TT system, U
c>=1.15U, wherein U is protected circuit rated line voltage.The horizontal U of described voltage protection
pfor 80% of the impulse withstand voltage value of protected equipment.
In step S2, when surge protector and protected equipment are installed in parallel in described step (2), make the lead-in wire at two ends of surge protector the shortest.Do like this can reduce because of long lead-in wire and introduce the infringement that extra residual voltage produces equipment, also farthest bring into play the protection effect of surge protector simultaneously.
Compared with prior art, tool has the following advantages and beneficial effect in the present invention:
1, the present invention, by distribution system in transformer station being carried out to the transformation of overvoltage protection, can effectively reduce the probability that in transformer station, secondary circuit breaks down.
2, the invention process is got up more conveniently, and does not need the original equipment of distribution system to remove or replace, and cost is lower.
Accompanying drawing explanation
Fig. 1 is the method flow diagram of a kind of substation bus bar of the present invention below terminal box over-voltage suppression;
Fig. 2 is the fundamental diagram of the surge protector of method described in Fig. 1;
Fig. 3 is the mode of connection schematic diagram of the surge protector of method described in Fig. 1;
Fig. 4 is effective guard space schematic diagram of the surge protector of method described in Fig. 1;
Secondary circuit induction voltage waveform figure when Fig. 5 is normal operation;
When Fig. 6 is switch operation and secondary side do not install the induction voltage waveform figure of SPD additional;
When Fig. 7 is switch operation and secondary side install the induction voltage waveform figure of SPD additional.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited to this.
As Fig. 1,2,3,4, the method for a kind of substation bus bar below terminal box over-voltage suppression, as Fig. 1, the step that comprises following order:
S1. the selection of surge protector
The position producing due to overvoltage in 500kV transformer station is secondary circuit, so the protective circuit installing additional is pressure limiting circuit, is mainly used to clamp down on voltage, i.e. residual voltage in limiting circuit, to protect secondary device; For II level pressure limiting circuit, require selected element non-linear good, withstand voltage level is low, often adopts piezoresistive surge protector;
According to maximum Uc U
c, the horizontal U of voltage protection
p, maximum discharge current I
maxand the response time select surge protector;
(1) determine maximum Uc U
c: it for being applied to continuously maximum a.c. voltage or the direct voltage at surge protector two ends in the temperature range of regulation, and wherein maximum a.c. voltage refers to the effective value of maximum a.c. voltage; In the time selecting surge protector, should consider normal fluctuation and the highest sustained fault voltage that electrical network may occur is installed, be divided into following situation:
A, in TT system, U
c>=1.55U
o, wherein U
ofor the specified phase voltage of protected circuit;
B, in TN system and TT system, U
c>=1.15U
o, wherein U
ofor the specified phase voltage of protected circuit;
C, in IT system and TT system, U
c>=1.15U, wherein U is protected circuit rated line voltage.
(2) the horizontal U of voltage protection
pselection: in order to characterize the parameter of deboost performance between surge protector terminal, its technical specification has 6kV, 4kV, 2.5kV, 1.5kV; The horizontal U of voltage protection
pwill be lower than the impulse withstand voltage value of protected equipment, for very important equipment, the horizontal U of voltage protection
pfor 80% of the impulse withstand voltage value of protected equipment; As table 1:
The table 1 three-phase system various device shock-resistant overvoltage rated value that insulate
| Device location | Shock-resistant overvoltage category | Shock-resistant voltage rating/kV |
| Electric device electric power incoming line place or near the equipment it | IV class | 6 |
| The equipment of distribution line and last branched line | III class | 4 |
| Power consumption equipment | II class | 2.5 |
| The equipment of special requirement protection | I class | 1.5 |
(3) maximum discharge current I
maxselection: according to whole lightning current I national standard " code for design of lightning protection of buildings " Suo Shu, by 50% earthing device that flows into building lightning protection device, other 50% is assigned on distribution system cable by the most cruel shunting mode;
By relevant specification requirement: to first order surge protector, maximum discharge current must be selected by the through-flow requirement of 10/350 μ s waveform; To what surge protector thereafter, discharging current can be selected by the through-flow requirement of 8/20 μ s waveform, but must convert, and surge protector is extrapolated the through-current capability of 8/20 μ s waveform of requirement by the through-flow requirement of 10/350 μ s waveform;
(4) setting of response time: protection requires to be not more than 100ns to the first order; Second level protection is required to be not more than 50ns; The 3rd utmost point protection is required to be not more than 25ns;
S2. the installation of surge protector
(1) determine that Substation secondary circuit produces superpotential position, and analyze the ground connection form of low-voltage distribution system;
(2) as Fig. 2, 3, surge protector and protected equipment are installed in parallel, make the lead-in wire at two ends of surge protector the shortest: between surge protector and protected equipment, conventionally all can have a segment distance, as the line segment b in Fig. 4, according to theory of travelling wave analysis, voltage on voltage and surge protector on protected equipment just has difference, it is distant effect, in the time that surge protector is installed, selecting the mode of installation site and line is an important link, make the lead-in wire at surge protector two ends the shortest as far as possible, reduce as far as possible and introduce the infringement that extra residual voltage produces equipment because of long lead-in wire, also farthest bring into play the protection effect of surge protector simultaneously, wherein, in Fig. 2, U represents to be applied to the voltage at surge protector two ends, and R represents the resistance of surge protector, U
drepresent surge protector trigger voltage, in Fig. 4 kt represent to invade circuit voltage wave (k is afferent echo steepness, unit be kV/ μ s), a represents to invade ripple from the distance that surge protector is installed, b represents the distance between surge protector and protected equipment,
S3. utilize oscilloscope to measure adding the waveform voltage signal that in the secondary circuit of surge protector, electric current is responded to, by the analysis to waveform, and and the contrast of the waveform of surveying while not installing surge protector additional, verify that surge protector has good inhibition to the overvoltage of coming that is coupled from primary side;
S31. in the time that equipment is in normal operation, on secondary circuit, install induction coil additional, and by the induced voltage in oscilloscope measurement loop, waveform is illustrated in fig. 5 shown below: (voltage magnitude is at 500V shelves)
S32. in the time of switch operation, and secondary circuit does not install surge protector additional, the voltage waveform that now secondary circuit is responded to, (voltage magnitude is 500V);
As can see from Figure 6, in switch operation moment, secondary circuit has induction overvoltage to produce, and amplitude is approximately 1kV;
S33. in the time of switch operation, and secondary circuit installs surge protector additional, the voltage waveform that now secondary circuit is responded to; (voltage magnitude is 500V)
As Fig. 7, when installing additional after surge protector (SPD), the size of the induction overvoltage that when switch operation, secondary side produces is approximately 500V.
In sum, the contrast of 3 waveforms that record is by experiment known, and in the time of switch operation, the temporary overvoltage that primary side produces can transmit secondary side by some coupling path, makes secondary circuit produce induction overvoltage.In addition, installing surge protector additional at secondary circuit has obvious effect to suppressing induction overvoltage, can be good at reducing the amplitude of induction overvoltage, and electrical secondary system has been played to protective effect.
Above-described embodiment is preferably execution mode of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under Spirit Essence of the present invention and principle, substitutes, combination, simplify; all should be equivalent substitute mode, within being included in protection scope of the present invention.
Claims (5)
1. a method for substation bus bar below terminal box over-voltage suppression, is characterized in that the step that comprises following order:
S1. the selection of surge protector
According to maximum Uc U
c, the horizontal U of voltage protection
p, maximum discharge current I
maxand the response time select surge protector, the wherein horizontal U of voltage protection
pwill be lower than the impulse withstand voltage value of protected equipment;
S2. the installation of surge protector
(1) determine that Substation secondary circuit produces superpotential position, and analyze the ground connection form of low-voltage distribution system;
(2) surge protector and protected equipment are installed in parallel;
S3. in the time of switch operation, the secondary circuit that installs surge protector is measured by oscilloscope, obtained waveform and data, prove to install additional surge protector to suppressing the superpotential feasibility of secondary circuit and validity.
2. the method for substation bus bar according to claim 1 below terminal box over-voltage suppression, is characterized in that described maximum Uc U
c, for can be applied to continuously maximum a.c. voltage or the direct voltage at surge protector two ends in the temperature range of regulation, wherein maximum a.c. voltage refers to the effective value of maximum a.c. voltage.
3. the method for substation bus bar according to claim 1 below terminal box over-voltage suppression, is characterized in that described maximum Uc U
c, in the time selecting surge protector, be divided into following situation:
(1) in TT system, U
c>=1.55U
o, wherein U
ofor the specified phase voltage of protected circuit;
(2) in TN system and TT system, U
c>=1.15U
o, wherein U
ofor the specified phase voltage of protected circuit;
(3) in IT system and TT system, U
c>=1.15U, wherein U is protected circuit rated line voltage.
4. the method for substation bus bar according to claim 1 below terminal box over-voltage suppression, is characterized in that the horizontal U of described voltage protection
pfor 80% of the impulse withstand voltage value of protected equipment.
5. the method for substation bus bar according to claim 1 below terminal box over-voltage suppression; it is characterized in that; in step S2, when surge protector and protected equipment are installed in parallel in described step (2), make the lead-in wire at two ends of surge protector the shortest.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410098837.4A CN103904633A (en) | 2014-03-17 | 2014-03-17 | Overvoltage suppressing method for terminal box below transformer substation bus |
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|---|---|---|---|
| CN201410098837.4A CN103904633A (en) | 2014-03-17 | 2014-03-17 | Overvoltage suppressing method for terminal box below transformer substation bus |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105021868A (en) * | 2015-07-20 | 2015-11-04 | 国家电网公司 | Simple method for measuring high-voltage circuit breaker switching-on overvoltage on site |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04207917A (en) * | 1990-11-30 | 1992-07-29 | Hitachi Ltd | Gas insulated electric apparatus |
| CN203310902U (en) * | 2013-06-08 | 2013-11-27 | 安顺供电局 | Overvoltage surge current tester for secondary system of transformer station |
-
2014
- 2014-03-17 CN CN201410098837.4A patent/CN103904633A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04207917A (en) * | 1990-11-30 | 1992-07-29 | Hitachi Ltd | Gas insulated electric apparatus |
| CN203310902U (en) * | 2013-06-08 | 2013-11-27 | 安顺供电局 | Overvoltage surge current tester for secondary system of transformer station |
Non-Patent Citations (3)
| Title |
|---|
| 中华人民共和国机械工业部: "《建筑物防雷设计规范》", 《建筑物防雷设计规范（2000年版）》 * |
| 洪滨等: "电涌保护器的应用与金山花园信息系统防雷设计", 《低压电器》 * |
| 翟帆: "变电所二次系统雷电电涌防护研究", 《中国优秀硕士学位论文全文数据库工程科技Ⅱ辑》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105021868A (en) * | 2015-07-20 | 2015-11-04 | 国家电网公司 | Simple method for measuring high-voltage circuit breaker switching-on overvoltage on site |
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Application publication date: 20140702 |