Topological structure of ultrahigh-voltage and ultrahigh-voltage multi-break quick vacuum circuit breaker
Technical Field
The invention relates to the field of rapid vacuum circuit breakers, in particular to a topological structure of an ultrahigh-voltage and ultrahigh-voltage multi-break rapid vacuum circuit breaker and a method for determining the number of breaks.
Background
In recent years, with the continuous enlargement of the scale of a power grid and the continuous rise of the voltage grade, the power utilization load is increased rapidly, and the phenomenon that the short-circuit current exceeds the standard frequently occurs. At present, no means is available for reliably cutting off the excessive short-circuit current under the ultra/extra-high voltage level. The rapid vacuum circuit breaker has the advantages of short switching-off time and low dispersibility, and the positive volt-ampere characteristic of the vacuum arc enables the design of the ultra/ultra-high voltage multi-break rapid vacuum circuit breaker by adopting a multi-break series-parallel combination mode to be possible.
The patent '363 kV circuit breaker based on quick repulsion switch' (201710692842.1) provides a circuit breaker topological structure which is connected in parallel and then connected in series, solves the problems of long on-off time and overlarge impact current of the traditional circuit breaker, and realizes reliable on-off of short-circuit current in the first half-wave (10 ms). However, due to the adoption of the structure of first parallel connection and second series connection, once a certain fracture fails, all current can flow through the fracture connected with the fracture in parallel, so that the failure probability of the parallel fracture is greatly increased, and the whole breaker fails. In addition, a circuit breaker topological structure which is connected in parallel and then connected in series is adopted, in order to realize balanced current sharing of each circuit breaker unit, the contact resistances of two circuit breakers which are connected in parallel in six units are required to be respectively ensured to be equal, and the requirements on the type selection of an arc extinguish chamber of the vacuum circuit breaker are extremely high.
Disclosure of Invention
The invention provides a topological structure of an ultrahigh-voltage and ultrahigh-voltage multi-break quick vacuum circuit breaker, which adopts a topological connection mode of first series connection and second parallel connection, the number of parallel branches and the number of series breaks of each branch are determined according to actual application conditions, the rated current capacity, the short circuit breaking capacity, the power frequency voltage withstanding capacity and the lightning impulse voltage withstanding capacity of the whole circuit breaker are greatly improved, and the circuit breaker can continue to normally operate after one break fails. Secondly, a topological connection mode of first series connection and then parallel connection is adopted, and the effect of balanced current sharing can be achieved only by ensuring that the total contact resistance of each parallel branch is equal. The quick vacuum circuit breaker can be applied to the ultra-high voltage and extra-high voltage grades of 363kV and above.
In order to achieve the purpose, the invention adopts the following technical scheme:
a topological structure of a quick vacuum circuit breaker with ultrahigh voltage and extra-high voltage multiple fractures comprises a plurality of identical quick vacuum circuit breaker units 9, a topological connection structure of connecting in series and then connecting in parallel is adopted, a plurality of identical branches are connected in parallel, each parallel branch is formed by connecting a plurality of identical quick vacuum circuit breaker units in series, arc extinguish chambers of the quick vacuum circuit breaker units at the head ends of all the parallel branches are connected with each other through conductive copper rods 3, and a top bus leading-out port of a first quick vacuum circuit breaker unit 9.1 in the first parallel branch is connected with a first leading-out sleeve 1; in each parallel branch, the arc extinguishing chamber movable outgoing line conductive copper rod 4 of the first rapid vacuum circuit breaker unit 9.1 is connected with the arc extinguishing chamber movable outgoing line conductive copper rod 4 of the second rapid vacuum circuit breaker unit 9.2, the arc extinguishing chamber static outgoing line conductive copper rod 3 of the second rapid vacuum circuit breaker unit 9.2 is connected with the arc extinguishing chamber static outgoing line conductive copper rod 3 of the third rapid vacuum circuit breaker unit 9.3, and so on; the arc extinguish chamber static outgoing line conductive copper rods 3 or arc extinguish chamber moving outgoing line conductive copper rods 4 of the rapid vacuum circuit breaker units at the tail ends of all the parallel branches are connected with each other, and a top bus leading-out port of the last rapid vacuum circuit breaker unit of the last parallel branch is connected with the second leading-out sleeve 2.
The number of the parallel branches is determined according to the rated current capacity of the circuit breaker, and the rated current of the target circuit breaker is divided by the rated current of the arc extinguishing chamber of the selected specification to obtain the number of the parallel branches of the target circuit breaker.
The number of the quick vacuum circuit breaker units connected in series with each parallel branch refers to the requirements of power frequency withstand voltage and lightning impulse withstand voltage of the circuit breaker, the power frequency withstand voltage and the lightning impulse withstand voltage of the target circuit breaker are divided by the power frequency withstand voltage and the lightning impulse withstand voltage of the fracture of the arc extinguish chamber of the selected specification respectively, a larger value is selected to be rounded upwards, and then 1 is added, so that the number of the quick vacuum circuit breaker units connected in series with each parallel branch is obtained.
In order to achieve the effect of balancing and equalizing the current of each branch, the electric equipment burnout caused by overlarge current and overhigh thermal power of a certain parallel branch is avoided, and the total contact resistance of all the serial quick vacuum circuit breaker units in each parallel branch is required to be equal.
The invention has the beneficial effects that:
compared with the prior art, the invention provides a novel topological structure of the circuit breaker and a fracture quantity determining mode, which are applied to ultrahigh-voltage and ultrahigh-voltage multi-fracture rapid vacuum circuit breakers. Secondly, by adopting a topological connection mode of first series connection and then parallel connection, the effect of balanced current sharing can be achieved only by ensuring that the total contact resistance of each parallel branch is equal, the requirement on the type selection of the vacuum arc extinguish chamber is greatly reduced, and the rapid vacuum circuit breaker is applied to ultrahigh voltage and ultrahigh voltage levels. A new idea is provided for applying the quick vacuum circuit breaker to a higher voltage level, and the further popularization of the quick vacuum circuit breaker in the field of switches is facilitated.
Drawings
FIG. 1 is a topological structure of an ultra/extra-high voltage multi-break quick vacuum circuit breaker according to the present invention.
Fig. 2 is a topological structure diagram of a 550kV voltage level multi-break quick vacuum circuit breaker.
Fig. 3 is a three-dimensional diagram of a 550kV voltage level multi-break quick vacuum circuit breaker.
Fig. 4 is a top three-dimensional view of a 550kV voltage class multi-break quick vacuum circuit breaker.
Wherein, 1 is the first sleeve pipe of drawing forth, 2 is the second sleeve pipe of drawing forth, 3 is the quiet electrically conductive copper pole of being qualified for the next round of competitions of explosion chamber, 4 is the electrically conductive copper pole of being qualified for the next round of competitions of explosion chamber movingly, 5 is the explosion chamber, 6 is the insulating stand, 7 is the repulsion operating mechanism, 8 is the jar body, 9 is quick vacuum circuit breaker unit, 9.1 is first quick vacuum circuit breaker unit, 9.2 is second quick vacuum circuit breaker unit, 9.3 is the third quick vacuum circuit breaker unit, 9.4 is the fourth quick vacuum circuit breaker unit, 9.5 is the fifth quick vacuum circuit breaker unit, 9.6 is the sixth quick vacuum circuit breaker unit.
Detailed Description
The invention is described in further detail below with reference to the following figures and specific examples:
as shown in fig. 1, the ultrahigh voltage and extra-high voltage multi-break quick vacuum circuit breaker topological structure of the invention comprises a plurality of same quick vacuum circuit breaker units 9, adopts a topological connection structure of first series and then parallel, and is formed by connecting a plurality of same circuit breaker units in parallel, wherein each parallel branch is formed by connecting a plurality of same circuit breaker units in series, arc extinguish chamber static outgoing line conductive copper rods 3 of the quick vacuum circuit breaker units at the head ends of all parallel branches are connected with each other, and a top bus outgoing port of a first quick vacuum circuit breaker unit 9.1 in a first parallel branch is connected with a first outgoing sleeve 1; in each parallel branch, the movable outgoing conductive copper rod 4 of the arc extinguish chamber of the first rapid vacuum circuit breaker unit 9.1 is connected with the movable outgoing conductive copper rod 4 of the arc extinguish chamber of the second rapid vacuum circuit breaker unit 9.2, the static outgoing conductive copper rod 3 of the arc extinguish chamber of the second rapid vacuum circuit breaker unit 9.2 is connected with the static outgoing conductive copper rod 3 of the arc extinguish chamber of the third rapid vacuum circuit breaker unit 9.3, and so on; the arc extinguish chamber static outgoing line conductive copper rods 3 or arc extinguish chamber moving outgoing line conductive copper rods 4 of the rapid vacuum circuit breaker units at the tail ends of all the parallel branches are connected with each other, and a top bus leading-out port of the last rapid vacuum circuit breaker unit of the last parallel branch is connected with the second leading-out sleeve 2. The first leading-out sleeve 1 and the second leading-out sleeve 2 are used for being connected into a substation bus.
The number of the parallel branches is determined according to the rated current capacity of the circuit breaker, and the rated current of the circuit breaker of the target voltage class is divided by the rated current of the arc extinguish chamber of the selected specification to obtain the number of the parallel branches of the multi-break quick vacuum circuit breaker.
The number of the quick vacuum circuit breaker units connected in series with each parallel branch refers to the requirements of power frequency withstand voltage and lightning impulse withstand voltage of the circuit breaker, the power frequency withstand voltage and the lightning impulse withstand voltage of the target circuit breaker are divided by the power frequency withstand voltage and the lightning impulse withstand voltage of the fracture of the arc extinguish chamber of the selected specification respectively, a larger value is selected to be rounded upwards, and then 1 redundancy is added, so that the number of the quick vacuum circuit breaker units connected in series with each parallel branch is obtained.
In order to achieve the effect of balancing and equalizing the current of each branch, the electric equipment burnout caused by overlarge current and overhigh thermal power of a certain parallel branch is avoided, and the total contact resistance of all the serial quick vacuum circuit breaker units in each parallel branch is required to be equal.
As shown in fig. 3 and 4, in the above technical solution, each fast vacuum circuit breaker unit 9 includes a tank 8, an arc extinguish chamber static outgoing line conductive copper rod 3, an arc extinguish chamber dynamic outgoing line conductive copper rod 4, an arc extinguish chamber 5, an insulating table 6, and a repulsion force operating mechanism 7, wherein the arc extinguish chamber 5, the insulating table 6, and the repulsion force operating mechanism 7 are all disposed in the tank 8, the repulsion force operating mechanism 7 is disposed at the bottom end of the tank 8, the telescopic end of the repulsion force operating mechanism 7 is connected to the bottom end of the insulating table 6, the top end of the insulating table 6 is connected to the bottom end of the arc extinguish chamber 5, and the two ends of the arc extinguish chamber 5 are respectively connected to the arc extinguish chamber static outgoing line conductive copper rod 3.
In the above technical solution, the repulsion operating mechanism 7 adopts a fast repulsion mechanism. The interior of the tank body 8 is in a vacuum environment.
As shown in fig. 2, the topology structure diagram of the 550kV voltage class multiple-break quick vacuum circuit breaker is a 550kV voltage class multiple-break quick vacuum circuit breaker composed of 12 quick vacuum circuit breaker units 9, and includes two identical parallel branches, each parallel branch is formed by connecting 6 identical quick vacuum circuit breaker units 9 in series.
In the technical scheme, the arc extinguish chamber 5 has the rated voltage of 72.5kV, the rated current of 2500A, the short-circuit on-off current of 80kA, the short-time power frequency withstand voltage of 160kV and the lightning impulse withstand voltage of 380 kV.
The rated current of the 550kV circuit breaker is 5000A, the short-time power frequency withstand voltage of a fracture is 740kV, and the lightning impulse withstand voltage is 1670 kV.
The number of the parallel branches is determined according to the rated current capacity of the circuit breaker, and the rated current of the 550kV circuit breaker is divided by the rated current of the 72.5kV arc extinguish chamber to obtain the number of the parallel branches of the multi-break quick vacuum circuit breaker. 5000/2500/2, the multi-break quick vacuum circuit breaker with 550kV voltage level is required to be formed by connecting two branches in parallel.
And dividing the power frequency withstand voltage of the 550kV circuit breaker by the power frequency withstand voltage of the 72.5kV arc extinguish chamber fracture by referring to the requirements of the power frequency withstand voltage and the lightning impulse withstand voltage of the circuit breaker according to the number of the series fractures, and rounding the obtained result upwards and adding 1 to obtain the number of the series fractures of each branch. 740 ÷ 160 ÷ 4.625, rounding up to 5, then add 1 to obtain 6; the lightning impulse withstand voltage is calculated according to 1670 ÷ 380 ═ 4.39, 5 is rounded up, and 6 is added. Considering that the fracture insulation level of the 550kV breaker can be met when 1 quick switch in the series-connected unit fails, each parallel branch of the 550kV voltage level multi-fracture quick vacuum breaker is formed by connecting 6 breaker units in series.