CN112952783B - Alternating current short circuit fault current limiter - Google Patents
Alternating current short circuit fault current limiter Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
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Abstract
The invention relates to an AC short-circuit fault current limiter, comprising: fast switches, split reactors, reactors and capacitors. The split reactor comprises a first winding and a second winding, wherein the magnetic fluxes are opposite. The series resonance circuit formed by the reactor and the capacitor resonates at the power frequency. When the power grid is in a steady state, the branch circuits where the first winding and the second winding are located are equal in current, magnetic fluxes are offset, and the current limiter presents small impedance or no impedance. After a fault occurs, the short-circuit current contains multiple harmonic components, and a series resonance circuit formed by the reactor and the capacitor presents impedance, so that the currents of branches where the first winding and the second winding are located are unequal, the current-limiting impedance of the split reactor is increased, and rapid automatic current limiting is realized. And then, the quick switch is disconnected and arcs are extinguished, and the current limiter further limits the short-circuit current. The current limiter can effectively limit the short-circuit current of the alternating current power grid and improve the operation reliability of the power grid.
Description
Technical Field
The invention relates to the field of short-circuit fault current limiters of transmission and distribution networks, in particular to an alternating-current short-circuit fault current limiter.
Background
With the increasing demand of society for electric power, the continuous development of electric power systems is driven, and the capacities of single machines and power plants, the capacities of substations and urban and industrial centers are increased, so that the electric power systems are interconnected, the short-circuit current level in each level of power grid is increased continuously, and the damage of short-circuit faults to the electric power systems and the electric equipment connected with the electric power systems is increased more and more. Moreover, while the demand for electric energy is increasing, people also put higher demands on the quality of electric energy, the reliability and the safety of power supply, and the like. However, the transient stability problem of large grids is prominent, one of the most important reasons being due to the lack of effective short-circuit current limiting technology in conventional power technologies. At present, the circuit breaker is widely used in the world to break the short-circuit current in full, because the level of the short-circuit current is directly related to the capacity of the system, under the condition that the rated breaking current level of the circuit breaker is certain, the capacity of the power system is limited by breaking the short-circuit current in full, the circuit breaker is expensive, and the price of the circuit breaker is rapidly increased along with the increase of the rated breaking current. As the capacity and size of power grids have increased, the breaking capability of circuit breakers has become increasingly difficult to adapt to the needs of grid operation.
Short-circuit fault current limiters provide a new idea for solving this problem. At present, based on the material characteristics and the technical breakthrough thereof, various current limiters are proposed and developed, including PTC current limiters, resonant current limiters, solid-state current limiters, superconducting current limiters, and the like. The current limiting capacity of the PTC current limiter is too small, so that the PTC current limiter cannot be applied to an actual power grid. When the solid-state current limiter is applied to a high-voltage large-capacity system, a large number of solid-state switching tubes (IGBT, GTO and the like) are required to be connected in series and in parallel to realize the solid-state current limiter, so that the solid-state current limiter has the disadvantages of complex structure, high price, large steady-state loss and low reliability, and therefore, the practical application of the solid-state current limiter is limited. In the document "development of 330kV switch-type zero-loss fault current limiting device and artificial short-circuit test" (vol. 3, No. 4 of smart grid 2015), a switch-type zero-loss fault current limiting device is introduced, and the current limiting of the grid is realized by switching a current limiting reactor through an intelligent fast switch. Although an intelligent fast switch is adopted, the current-limiting reactor can be put into the fault circuit after the first zero crossing point, and the first peak of the short-circuit current cannot be limited. The document "transient recovery voltage suppression analysis when a 500kV current-limiting reactor is connected into a 90kA short-circuit current system" (southern power grid technology 2020, volume 13, 12) describes a current limiter comprising a vacuum fast switch and a splitting reactor. The current-limiting reactor can be put into the reactor after the first zero crossing point after the fault, and the first peak of the short-circuit current cannot be limited. The first wave crest impact current of the short-circuit current is large, and great impact force is generated on power grid equipment such as a transformer, so that the transformer is deformed and even damaged.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides an alternating current short-circuit fault current limiter which is simple in structure, low in cost and capable of effectively limiting the short-circuit current of an alternating current power grid.
The technical scheme adopted by the invention is as follows: an alternating current short-circuit fault current limiter comprises a quick switch K, a splitting reactor M, a reactor L1 and a capacitor C1; wherein the split reactor M comprises a first winding L01 and a second winding L02;
the first winding L01 of the split reactor M is sequentially connected with the fast switch K, the reactor L1 and the capacitor C1 in series and then connected with the second winding L02 in parallel;
one end of a first winding L01 of the split reactor M and one end of a second winding L02 are connected with a first connection point P1, the other end of the first winding L01 of the split reactor M and one end of a fast switch K are connected through a second connection point P2, the other end of the fast switch K is connected with one end of a reactor L1 through a third connection point P3, the other end of the reactor L1 is connected with one end of a capacitor C1 through a fourth connection point P4, the other end of the capacitor C1 is connected with a fifth connection point P5, the other end of the second winding L02 is connected with a sixth connection point P6, and the fifth connection point P5 is directly connected with the sixth connection point P6. An AC power source Uac is connected between a first connection point P1 and the ground, a circuit breaker SW and a load R L The series connection is formed between the fifth connection point P5 and the ground to form an alternating current short-circuit fault current limiter.
Further, the split reactor M is either an iron core coupling structure, an up-down coupling structure, or an internal-external coupling structure; if the split reactor M is in an iron Core coupling structure, the split reactor M comprises a first winding L01, a second winding L02 and an iron Core; b1 and B2 respectively indicate the magnetic flux directions of the first winding L01 and the second winding L02, the self-inductances of the first winding L01 and the second winding L02 are equal, the magnetic flux directions are opposite, and a closed magnetic circuit is formed by closing an iron core, so that the magnetic field coupling capacity of the closed magnetic circuit is improved; if the split reactor M is in a top-bottom coupling structure, the split reactor M comprises a first winding L01 and a second winding L02, wherein B1 and B2 respectively represent the magnetic flux directions of the first winding L01 and the second winding L02, the self-inductance of the first winding L01 and the self-inductance of the second winding L02 are equal, and the magnetic flux directions are opposite; if the split reactor M is in an internal-external coupling structure, the split reactor M comprises a first winding L01 and a second winding L02, wherein B1 and B2 respectively represent the magnetic flux directions of the first winding L01 and the second winding L02, and the first winding L01 and the second winding L02 have equal self-inductance and opposite magnetic flux directions.
Furthermore, the quick switch K is a quick vacuum circuit breaker or a quick mechanical circuit breaker, and the action time of the quick switch K, namely the time from receiving the action command to completing the opening action, is less than 20 ms.
Further, the reactor L1 and the capacitor C1 form a series resonant circuit, and the resonant frequency f is power frequency, that is:
ω 2 L 1 C 1 ＝1 (1)
wherein L is 1 Is the inductance, C, of reactor L1 1 The angular frequency ω is 2 pi f, and f is the resonance frequency, which is the capacitance of the capacitor C1.
Further, when the power grid runs in a steady state, namely no short-circuit fault exists, the quick switch K is in a closed state, and the reactor L1 and the capacitor C1 resonate at power frequency; the resonant circuit formed by the reactor L1 and the capacitor C1 does not generate impedance, the first winding L01 and the second winding L02 share line current, and the current limiter presents low impedance or zero impedance and does not influence the power grid.
In the event of short-circuit failure, i.e. load R L The short circuit to the ground occurs, after the system detects the short-circuit fault, the fast switch K acts fast to realize the opening of the brake, the current is transferred to the branch of the second winding L02 from the branch of the first winding L01, then the current limiting is realized separately by the second winding L02, the arc extinguishing is finished by the fast switch K action as the boundary, and the current limiting process of the alternating current short-circuit fault current limiter is divided into two stages:
the first stage is as follows: before the fast switch K is used for arc extinction, the branch circuits of the first winding L01 and the second winding L02 are conducted; meanwhile, because multiple harmonic components exist in the continuously-changed short-circuit current, the impedance presented by a series circuit formed by the reactor L1 and the capacitor C1 is not zero, so that the currents of branches where the first winding L01 and the second winding L02 are located are not equal, the magnetic fluxes of the first winding L01 and the second winding L02 are not equal, the impedance of the split reactor M is increased due to the difference of the magnetic fluxes, the current limiter generates current-limiting impedance, and the limitation on the short-circuit current is implemented;
and a second stage: after the fast switch K is used for arc extinction, the current of the branch of the first winding L01 is completely transferred to the branch where the second winding L02 is located, and is limited by the second winding L02 alone;
and finally, the line breaker SW breaks the short-circuit current to finish the current limiting and fault removal of the short-circuit current by the alternating-current short-circuit fault current limiter.
Further, a first winding L01 of the split reactor M is connected with the fast switch K in series, a second winding L02 is connected with the reactor L1 and the capacitor C1 in series in sequence, and then two branches are connected in parallel; one end of a first winding L01 and one end of a second winding L02 of the split reactor M are connected with a first connection point P1, the other end of the first winding L01 and one end of a quick switch K are connected through a second connection point P2, the other end of the quick switch K is connected with a fifth connection point P5, the other end of the second winding L02 is connected with one end of a reactor L1 through a third connection point P3, the other end of the reactor L1 is connected with one end of a capacitor C1 through a fourth connection point P4, and the other end of the capacitor C1 is connected with the fifth connection point P5.
Further, a resistor R0 is connected in series in the branch of the second winding L02, and the resistor R0 is connected between the fifth connection point P5 and the sixth connection point P6;
the resistance value of the reactor L1 is R 0 Considering the possible effect on the current distribution of the first winding branch L01 and the second winding branch L02, the impedance Z of the series circuit of the reactor L1 and the capacitor C1 is expressed as:
wherein L is 1 Is the inductance, R, of the reactor L1 0 Is the resistance value, C, of the reactor L1 1 Is a capacitorThe capacitance of C1 has an angular frequency ω 2 pi f, where f is the resonance frequency and j is the imaginary unit. Simplified from equation (1) can be:
Z＝R 0 (3)
therefore, a resistor R0 with the resistance value of R is connected in series in the branch of the second winding L02 0 Therefore, the impedances of the first winding branch L01 and the second winding branch L02 are equal and the currents are equally distributed when the power grid is in a steady state, so that the magnetic fluxes of the first winding branch L01 and the second winding branch L02 are mutually counteracted, and the impedance presented by the current limiter to a line is minimum.
Further, a resistor R0 is connected in series in the branch of the first winding L01, and the resistor R0 is connected between the fifth connection point P5 and the sixth connection point P6.
The invention has the main advantages that:
1. the alternating current short-circuit fault current limiter effectively limits the peak value and the effective value of short-circuit current and improves the current limiting capability of the current limiter by matching the split reactor with the quick switch, the capacitor, the inductor and the like, thereby achieving better current limiting effect than the existing current limiter.
2. The reactor and the capacitor of the invention are in a resonance state without loss when the power grid is in a steady state, and the split reactor has reverse magnetic flux coupling, thereby not influencing the steady operation of the power grid.
3. The alternating current short-circuit fault current limiter can automatically respond to faults and automatically limit short-circuit current, and the fault response speed is high.
4. The main components of the alternating current short-circuit fault current limiter are mature in technology, easy to realize and beneficial to realizing industrialization of the current limiter.
Drawings
FIG. 1 is a schematic circuit diagram of an embodiment 1 of the present invention;
fig. 2(a) is a schematic diagram of a split-core reactor with an iron core coupling structure according to embodiment 1 of the present invention;
fig. 2(b) is a schematic diagram of a split-core reactor with an upper and lower coupling structure according to embodiment 1 of the present invention;
fig. 2(c) is a schematic diagram of a split-core reactor with an internal-external coupling structure in embodiment 1 of the present invention;
FIG. 3 is a typical grid short circuit current waveform;
FIG. 4 is a schematic circuit diagram of embodiment 2 of the present invention;
FIG. 5 is a schematic circuit diagram of embodiment 3 of the present invention;
FIG. 6 is a schematic circuit diagram of embodiment 4 of the present invention;
fig. 7 is a waveform diagram of the current of the power grid before and after the ac short-circuit fault current limiter of the present invention is connected to the power grid.
Detailed Description
The invention is further described with reference to the following figures and specific embodiments:
as shown in fig. 1, embodiment 1 of the present invention is an ac short-circuit fault current limiter. The current limiter comprises a fast switch K, a splitting reactor M, a reactor L1 and a capacitor C1. The split reactor M is composed of a first winding L01 and a second winding L02.
The first winding L01 of the split reactor M is connected in series with the fast switch K, the reactor L1 and the capacitor C1 in sequence and then connected in parallel with the second winding L02. One end of a first winding L01 of the split reactor M and one end of a second winding L02 are connected with a first connection point P1, the other end of the first winding L01 of the split reactor M is connected with one end of a fast switch K through a second connection point P2, the other end of the fast switch K is connected with one end of a reactor L1 through a third connection point P3, the other end of the reactor L1 is connected with one end of a capacitor C1 through a fourth connection point P4, the other end of the capacitor C1 is connected with a fifth connection point P5, the other end of the second winding L02 is connected with a sixth connection point P6, and the fifth connection point P5 is directly connected with the sixth connection point P6. An AC power source Uac is connected between a first connection point P1 and the ground, a circuit breaker SW and a load R L The series connection is formed between the fifth connection point P5 and the ground to form an alternating current short-circuit fault current limiter.
The split reactor M according to embodiment 1 of the present invention is either an iron core coupling structure, an up-down coupling structure, or an internal-external coupling structure. Fig. 2(a) shows a Core coupling structure of a split reactor M, which is composed of a first winding L01, a second winding L02, and a Core. Wherein, B1 and B2 respectively show the magnetic flux direction of the first winding L01 and the second winding L02, the self-inductance of the first winding L01 and the self-inductance of the second winding L02 are equal, the magnetic flux direction is opposite, and a closed magnetic circuit is formed by closing the iron core, so that the magnetic field coupling capability of the magnetic circuit is improved. Fig. 2(B) shows an up-and-down coupling structure of a split reactor M, which is composed of a first winding L01 and a second winding L02, wherein B1 and B2 respectively represent the magnetic flux directions of the first winding L01 and the second winding L02, and the first winding L01 and the second winding L02 have equal self-inductance and opposite magnetic flux directions. Fig. 2(c) shows an internal and external coupling structure of a split-core reactor M, where the split-core reactor M is composed of a first winding L01 and a second winding L02, where B1 and B2 respectively indicate the magnetic flux directions of the first winding L01 and the second winding L02, and the self-inductances of the first winding L01 and the second winding L02 are equal and the magnetic flux directions are opposite.
The fast switch K of embodiment 1 of the present invention is a fast vacuum circuit breaker, or a fast mechanical circuit breaker. The action time of the fast switch K, namely the time from receiving the action command to completing the opening action, is less than 20 ms.
The reactor L1 and the capacitor C1 in embodiment 1 of the present invention form a series resonant circuit, and the resonant frequency f is the power frequency (f is 50Hz), that is, the resonant frequency f is the frequency of the power frequency
ω 2 L 1 C 1 ＝1 (1)
Wherein L is 1 Is the inductance, C, of reactor L1 1 The angular frequency ω is 2 pi f, and f is the resonance frequency, which is the capacitance of the capacitor C1.
When the power grid runs in a steady state, namely no short-circuit fault exists, the quick switch K is in a closed state, and the reactor L1 and the capacitor C1 resonate at power frequency. In general, the resistance of reactor L1 is negligible. The resonant circuit formed by the reactor L1 and the capacitor C1 does not generate impedance, and the first winding L01 and the second winding L02 share line current. The current limiter presents low impedance or zero impedance, and has no influence on the power grid.
Upon occurrence of a short-circuit fault, i.e. the load R L A short circuit to ground occurs and the line current increases rapidly. The current through the branch in which the first winding L01 and the second winding L02 are located increases rapidly. System for controlling a power supplyAfter the short-circuit fault is detected, the fast switch K acts fast to realize switching-off, the current is transferred to the branch where the second winding L02 is located from the branch where the first winding L01 is located, and then the current is limited by the second winding L02 alone. Since the fast switch K takes a while from start-up, current diversion and arc extinction to current limiting. Therefore, the current limiting process of the alternating current short-circuit fault current limiter is divided into two stages by taking the action of the quick switch K to complete arc extinction as a boundary.
The first stage is as follows: that is, before the fast switch K arcs, the branch current of the first winding L01 and the branch current of the second winding L02 are conducted. Meanwhile, because multiple harmonic components exist in the continuously-changing short-circuit current, the impedance presented by the series circuit formed by the reactor L1 and the capacitor C1 is not zero, so that the currents of the branches where the first winding L01 and the second winding L02 are not equal, the magnetic fluxes of the first winding L01 and the second winding L02 are not equal, and the impedance of the split reactor M is increased due to the difference of the magnetic fluxes. Therefore, the current limiter generates a current limiting impedance, and limits the short-circuit current.
Fig. 3 shows a typical grid short circuit current waveform. The continuously changing short-circuit current has multiple harmonic components, so that the frequency characteristic of the line current changes, and a series circuit formed by the reactor L1 and the capacitor C1 presents certain impedance to the outside.
And a second stage: that is, after the fast switch K is extinguished, the current of the branch of the first winding L01 is completely transferred to the branch where the second winding L02 is located, and is separately limited by the second winding L02.
And finally, the line breaker SW breaks the short-circuit current to finish the current limiting and fault removal of the short-circuit current by the alternating-current short-circuit fault current limiter. Therefore, a scheme of the alternating current short-circuit fault current limiter is formed by connecting a quick switch, a capacitor and a series resonance circuit of the reactor in a branch of the split reactor, and the purposes of limiting the peak value of the short-circuit current and limiting the steady-state value of the short-circuit current are achieved. Meanwhile, before the rapid switching action, the resonant circuit of the capacitor and the reactor generates impedance, short-circuit current limitation is realized, the fault response speed is high, and the current limiting capability of the current limiter is improved.
Fig. 4 shows an ac short-circuit fault current limiter according to embodiment 2 of the present invention. The current limiter comprises a fast switch K, a splitting reactor M, a reactor L1 and a capacitor C1. The split reactor M is composed of a first winding L01 and a second winding L02.
The first winding L01 of the split reactor M is connected in series with the fast switch K, the second winding L02 is connected in series with the reactor L1 and the capacitor C1 in turn, and then the two branches are connected in parallel. One end of a first winding L01 and one end of a second winding L02 of the split reactor M are connected with a first connection point P1, the other end of the first winding L01 and one end of a quick switch K are connected through a second connection point P2, the other end of the quick switch K is connected with a fifth connection point P5, the other end of the second winding L02 is connected with one end of a reactor L1 through a third connection point P3, the other end of the reactor L1 is connected with one end of a capacitor C1 through a fourth connection point P4, and the other end of the capacitor C1 is connected with the fifth connection point P5. An AC power source Uac is connected between a first connection point P1 and the ground, a circuit breaker SW and a load R L The series connection is formed between the fifth connection point P5 and the ground to form an alternating current short-circuit fault current limiter.
The split reactor M according to embodiment 2 of the present invention has the same composition, structure, and operation principle as the split reactor M according to embodiment 1.
The fast switch K of embodiment 2 of the present invention has the same composition, structure and operation principle as the fast switch K of embodiment 1.
The reactor L1 and the capacitor C1 of embodiment 2 of the present invention and the series circuit thereof have the same composition, structure and operation principle as the reactor L1 and the capacitor C1 of embodiment 1 and the series circuit thereof.
When the power grid runs in a steady state, namely no short-circuit fault exists, the quick switch K is in a closed state, and the reactor L1 and the capacitor C1 resonate at power frequency. In general, the resistance of reactor L1 is negligible. The resonant circuit formed by the reactor L1 and the capacitor C1 does not generate impedance, and the first winding L01 and the second winding L02 share line current. The current limiter presents low impedance or zero impedance, and has no influence on the power grid.
Upon occurrence of a short-circuit fault, i.e. the load R L Short circuit to ground, wireThe path current increases rapidly. The current through the branch in which the first winding L01 and the second winding L02 are located increases rapidly. After the system detects a short-circuit fault, the quick switch K quickly acts to realize opening, current is transferred to a branch where the second winding L02 is located from a branch where the first winding L01 is located, and then the current is limited by the second winding L02, the reactor L1 and the capacitor C1. Since the fast switch K takes a while from start-up, current diversion and arc extinction to current limiting. Therefore, the current limiting process of the alternating current short-circuit fault current limiter is divided into two stages by taking the action of the quick switch K to complete arc extinction as a boundary.
The first stage is as follows: that is, before the fast switch K arcs, the branch current of the first winding L01 and the branch current of the second winding L02 are conducted. Meanwhile, because multiple harmonic components exist in the continuously-changing short-circuit current, the impedance presented by the series circuit formed by the reactor L1 and the capacitor C1 is not zero, so that the currents of the branches where the first winding L01 and the second winding L02 are not equal, the magnetic fluxes of the first winding L01 and the second winding L02 are not equal, and the impedance of the split reactor M is increased due to the difference of the magnetic fluxes. Therefore, the current limiter generates a current limiting impedance, and limits the short-circuit current.
And a second stage: that is, after the fast switch K quenches, the current of the branch of the first winding L01 is completely transferred to the branch of the second winding L02, and is commonly limited by the second winding L02, the reactor L1 and the capacitor C1.
And finally, the line breaker SW breaks the short-circuit current to finish the current limiting and fault removal of the short-circuit current by the alternating-current short-circuit fault current limiter. Therefore, a scheme of the alternating current short-circuit fault current limiter is formed by connecting a quick switch, a capacitor and a resonance circuit of the reactor in a branch of the split reactor, and the purposes of limiting the peak value of the short-circuit current and limiting the steady-state value of the short-circuit current are achieved. Meanwhile, before the rapid switching action, the resonant circuit of the capacitor and the reactor generates impedance, short-circuit current limitation is realized, the fault response speed is high, and the current limiting capability of the current limiter is improved.
Fig. 5 shows an ac short-circuit fault current limiter according to embodiment 3 of the present invention. The invention is based on the specific embodiment 1 shown in fig. 1, and is formed by connecting a resistor R0 in series with the branch of the second winding L02. The fast switch K, the split reactor M, the reactor L1, and the capacitor C1 in embodiment 3 correspond to those in fig. 1 one to one. The resistor R0 is connected between the fifth connection point P5 and the sixth connection point P6. The circuit structure of the rest part is the same as that of fig. 1.
Normally, the resistance of the reactor L1 is small (resistance value R) 0 ) However, considering the influence that may be caused to the current distribution of the first winding L01 branch and the second winding L02 branch, the impedance Z of the series circuit of the reactor L1 and the capacitor C1 is represented as:
wherein L is 1 Is the inductance, R, of the reactor L1 0 Is the resistance value, C, of the reactor L1 1 The capacitance of the capacitor C1 is represented by an angular frequency ω 2 pi f, where f is the resonance frequency and j is an imaginary unit. Simplified from equation (1) can be:
Z＝R 0 (3)
therefore, a resistor R0 with the resistance value of R is connected in series in the branch of the second winding L02 0 . Therefore, the impedances of the first winding branch L01 and the second winding branch L02 are equal and the currents are equally distributed when the power grid is in a steady state, so that the magnetic fluxes of the first winding branch L01 and the second winding branch L02 are mutually counteracted, and the impedance presented by the current limiter to a line is minimum.
The working principle of embodiment 3 of the present invention is the same as embodiment 1.
Fig. 6 shows an ac short-circuit fault current limiter according to embodiment 4 of the present invention. The invention is based on the embodiment 2 shown in fig. 4, and is formed by connecting a resistor R0 in series with the branch of the first winding L01. The fast switch K, the split reactor M, the reactor L1, and the capacitor C1 in embodiment 4 correspond to those in fig. 4 one to one. The resistor R0 is connected between the fifth connection point P5 and the sixth connection point P6. The circuit structure of the rest part is the same as that of fig. 4.
Normally, the resistance of the reactor L1 is small (resistance value R) 0 ) When considering the possible influence on the current distribution of the branch of the first winding L01 and the branch of the second winding L02, a resistor R0 with the resistance value of R0 is connected in series with the branch of the second winding L02 0 . The characteristics, values and effects of the resistor R0 are the same as those of the resistor R0 in the specific embodiment 3.
The working principle of embodiment 4 of the present invention is the same as embodiment 2.
Fig. 7 is a waveform diagram of the current of the power grid before and after the ac short-circuit fault current limiter of the present invention is connected to the power grid, which comparatively illustrates that the current limiter of the present invention can effectively limit the peak value and the effective value of the short-circuit current. In a power distribution network and a 220-500 kV power transmission network, the current limiting method can well realize short-circuit fault current limiting.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (8)
1. An alternating current short circuit fault current limiter, characterized by: the current limiter comprises a quick switch K, a splitting reactor M, a reactor L1 and a capacitor C1; wherein the split reactor M comprises a first winding L01 and a second winding L02;
the first winding L01 of the split reactor M is sequentially connected with the fast switch K, the reactor L1 and the capacitor C1 in series and then connected with the second winding L02 in parallel;
one end of a first winding L01 and one end of a second winding L02 of the split reactor M are connected with a first connection point P1, the other end of the first winding L01 of the split reactor M and one end of a quick switch K are connected through a second connection point P2, the other end of the quick switch K and one end of a reactor L1 are connected through a third connection point P3, the other end of the reactor L1 and one end of a capacitor C1 are connected through a fourth connection point P4, the other end of the capacitor C1 is connected with a fifth connection point P5, and the other end of the second winding L02 is connected with a sixth connection point P02The connection point P6 is connected, and the fifth connection point P5 is directly connected with the sixth connection point P6; an AC power source Uac is connected between a first connection point P1 and the ground, a circuit breaker SW and a load R L The series connection is formed between the fifth connection point P5 and the ground to form an alternating current short-circuit fault current limiter.
2. An ac short-circuit fault current limiter according to claim 1, wherein said split reactor M is either an iron core coupling structure, an up-down coupling structure, or an internal-external coupling structure; if the split reactor M is in an iron Core coupling structure, the split reactor M comprises a first winding L01, a second winding L02 and an iron Core; b1 and B2 respectively indicate the magnetic flux directions of the first winding L01 and the second winding L02, the self-inductances of the first winding L01 and the second winding L02 are equal, the magnetic flux directions are opposite, and a closed magnetic circuit is formed by closing an iron core, so that the magnetic field coupling capacity of the closed magnetic circuit is improved; if the split reactor M is in a top-bottom coupling structure, the split reactor M comprises a first winding L01 and a second winding L02, wherein B1 and B2 respectively represent the magnetic flux directions of the first winding L01 and the second winding L02, the self-inductance of the first winding L01 and the self-inductance of the second winding L02 are equal, and the magnetic flux directions are opposite; if the split reactor M is in an internal-external coupling structure, the split reactor M comprises a first winding L01 and a second winding L02, wherein B1 and B2 respectively represent the magnetic flux directions of the first winding L01 and the second winding L02, and the first winding L01 and the second winding L02 have equal self-inductance and opposite magnetic flux directions.
3. An ac short-circuit fault current limiter according to claim 1, wherein said fast switch K is a fast vacuum circuit breaker or a fast mechanical circuit breaker, and the actuation time of the fast switch K, i.e. the time from receiving the actuation command to completing the opening operation, is less than 20 ms.
4. An ac short-circuit fault current limiter according to claim 1, wherein said reactor L1 and capacitor C1 form a series resonant circuit, the resonant frequency f is the power frequency, i.e.:
ω 2 L 1 C 1 ＝1 (1)
wherein L is 1 Is the inductance, C, of reactor L1 1 The angular frequency ω is 2 pi f, and f is the resonance frequency, which is the capacitance of the capacitor C1.
5. An AC short-circuit fault current limiter according to any one of claims 1 to 4,
when the power grid runs in a steady state, namely no short-circuit fault exists, the quick switch K is in a closed state, and the reactor L1 and the capacitor C1 resonate at power frequency; a resonant circuit formed by the reactor L1 and the capacitor C1 does not generate impedance, the first winding L01 and the second winding L02 share line current, and the current limiter presents low impedance or zero impedance and does not influence the power grid;
in the event of short-circuit failure, i.e. load R L When a ground short circuit occurs, and a system detects a short-circuit fault, the quick switch K quickly acts to realize brake separation, current is transferred to a branch of the second winding L02 from a branch of the first winding L01, and then the current is independently limited by the second winding L02; the arc extinction is completed by the action of a quick switch K as a boundary, and the current limiting process of the alternating current short-circuit fault current limiter is divided into two stages:
the first stage is as follows: before the fast switch K is used for arc extinction, the branch circuits of the first winding L01 and the second winding L02 are conducted; meanwhile, because multiple harmonic components exist in the continuously-changed short-circuit current, the impedance presented by a series circuit formed by the reactor L1 and the capacitor C1 is not zero, so that the currents of branches where the first winding L01 and the second winding L02 are located are not equal, the magnetic fluxes of the first winding L01 and the second winding L02 are not equal, the impedance of the split reactor M is increased due to the difference of the magnetic fluxes, the current limiter generates current-limiting impedance, and the limitation on the short-circuit current is implemented;
and a second stage: after the fast switch K is used for arc extinction, the current of the branch of the first winding L01 is completely transferred to the branch where the second winding L02 is located, and is limited by the second winding L02 alone;
and finally, the line breaker SW breaks the short-circuit current to finish the current limiting and fault removal of the short-circuit current by the alternating-current short-circuit fault current limiter.
6. An ac short-circuit fault current limiter according to any one of claims 1 to 4 wherein, alternatively, the first winding L01 of the split reactor M is connected in series with the fast switch K, the second winding L02 is connected in series with the reactor L1 and the capacitor C1 in turn, and then the two branches are connected in parallel; one end of a first winding L01 and one end of a second winding L02 of the split reactor M are connected with a first connection point P1, the other end of the first winding L01 and one end of a quick switch K are connected through a second connection point P2, the other end of the quick switch K is connected with a fifth connection point P5, the other end of the second winding L02 is connected with one end of a reactor L1 through a third connection point P3, the other end of the reactor L1 is connected with one end of a capacitor C1 through a fourth connection point P4, and the other end of the capacitor C1 is connected with the fifth connection point P5.
7. An ac short-circuit fault current limiter according to any one of claims 1 to 4, wherein a resistor R0 is connected in series with the branch of the second winding L02, and a resistor R0 is connected between the fifth connection point P5 and the sixth connection point P6;
the resistance value of the reactor L1 is R 0 Considering the possible effect on the current distribution of the first winding branch L01 and the second winding branch L02, the impedance Z of the series circuit of the reactor L1 and the capacitor C1 is expressed as:
wherein L is 1 Is the inductance, R, of the reactor L1 0 Is the resistance value, C, of the reactor L1 1 The capacitance of the capacitor C1, the angular frequency ω 2 pi f, f the resonance frequency, j the imaginary unit; simplified by equation (1) can be obtained:
Z＝R 0 (3)
therefore, a resistor R0 with the resistance value of R is connected in series in the branch of the second winding L02 0 Therefore, the impedances of the first winding branch L01 and the second winding branch L02 are equal and the currents are equally distributed when the power grid is in a steady state, and therefore the magnetic fluxes of the first winding branch L01 and the second winding branch L02 are mutually offset and limitedThe current transformer presents the least impedance to the line.
8. An AC short-circuit fault current limiter according to claim 6, wherein a resistor R0 is connected in series with the branch of the first winding L01, and a resistor R0 is connected between the fifth connection point P5 and the sixth connection point P6.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004350337A (en) * | 2003-05-20 | 2004-12-09 | National Institute Of Advanced Industrial & Technology | Power flow controller with current limiting function |
| CN103078306A (en) * | 2013-01-09 | 2013-05-01 | 中国科学院电工研究所 | Fault current limiter on basis of combined rapid switch-on switch |
| CN103840442A (en) * | 2014-03-12 | 2014-06-04 | 中国科学院电工研究所 | Short-circuit fault current limiter |
| CN103928214A (en) * | 2014-03-26 | 2014-07-16 | 中国科学院电工研究所 | Double-column double-split reactor applied to current limiter |
| CN107863765A (en) * | 2017-11-06 | 2018-03-30 | 山东大学 | Improve arc current transfevent AC fault current limiter and current-limiting method |
| CN111384709A (en) * | 2020-03-09 | 2020-07-07 | 中国科学院电工研究所 | High-voltage high-capacity split reactance type current limiter |
-
2021
- 2021-02-04 CN CN202110154555.1A patent/CN112952783B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004350337A (en) * | 2003-05-20 | 2004-12-09 | National Institute Of Advanced Industrial & Technology | Power flow controller with current limiting function |
| CN103078306A (en) * | 2013-01-09 | 2013-05-01 | 中国科学院电工研究所 | Fault current limiter on basis of combined rapid switch-on switch |
| CN103840442A (en) * | 2014-03-12 | 2014-06-04 | 中国科学院电工研究所 | Short-circuit fault current limiter |
| CN103928214A (en) * | 2014-03-26 | 2014-07-16 | 中国科学院电工研究所 | Double-column double-split reactor applied to current limiter |
| CN107863765A (en) * | 2017-11-06 | 2018-03-30 | 山东大学 | Improve arc current transfevent AC fault current limiter and current-limiting method |
| CN111384709A (en) * | 2020-03-09 | 2020-07-07 | 中国科学院电工研究所 | High-voltage high-capacity split reactance type current limiter |
Non-Patent Citations (1)
| Title |
|---|
| 应用于谐振型限流器的双分裂铁心电抗器研究;邱清泉 等;《电工技术学报》;20170228;第32卷(第3期);第1-8页 * |
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