CN113193548B

CN113193548B - Limited interconnected double-ring type cable distribution network structure

Info

Publication number: CN113193548B
Application number: CN202110337916.6A
Authority: CN
Inventors: 姜建; 金涛; 焦建立; 刘欣宇; 石霄峰; 赵斌炎; 李衡; 曹青; 袁喆; 王炜
Original assignee: Live Working Branch Of Zhejiang Dayou Industrial Co ltd
Current assignee: Live Working Branch Of Zhejiang Dayou Industrial Co ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2022-05-31
Anticipated expiration: 2041-03-30
Also published as: CN113193548A

Abstract

The invention belongs to the technical field of electric power, and particularly relates to a limited-interconnection double-ring cable distribution network structure which comprises a first cable, a second cable and at least two ring network units, wherein the first cable and the second cable form a double-ring cable distribution network, the at least two ring network units are arranged on the first cable and the second cable, the interconnection cables are used in the head ring network unit and the tail ring network unit of the double-ring cable distribution network, and the first cable and the second cable in the head ring network unit and the tail ring network unit are interconnected to increase a load switching power supply and a power switching path. According to the invention, the interconnection cables are used in the head and tail two ring network units and the ring opening point ring network unit of the double-ring cable distribution network, and the first cable and the second cable in the head and tail two ring network units and the ring opening point ring network unit are interconnected to increase the load switching power supply and the power supply switching path, so that the load rate of each cable line in the double-ring cable distribution network structure during normal operation is improved; the potential misoperation hazard caused by excessive interconnection and subjective random interconnection is avoided, and a friendly grid environment is provided.

Description

Limited interconnected double-ring type cable distribution network structure

Technical Field

The invention belongs to the technical field of electric power, and particularly relates to a limited-interconnection double-ring type cable distribution network structure.

Background

Cable distribution networks generally have both single-loop and double-loop configurations.

The single-loop configuration, which has only one opposite side power supply, as shown in fig. 1, is generally used in urban and rural areas where the reliability requirements for power supply are not particularly high. The dual ring structure is used in a core area such as a central city where the requirement on power supply reliability is high, as shown in fig. 2.

Usually, double-ring type cable distribution network structure, its essence is formed by the combination of two single-ring type structures that do not have interconnection point completely and do not communicate, as shown in fig. 2, this kind of mode is when carrying out the load changeover, for every circuit, because the offside power is only 1, the switching supplies the route also only 1, when this offside power can not satisfy the switching supplies condition because of the trouble, load bearing capacity, can lead to the unable switching supplies of switching supplies circuit, can only be forced to have a power failure, house number loss when leading to, influence the power supply reliability. Especially, when outgoing line transformer substation bus overhauls, need accompany and stop the line load and change the confession by contralateral line, if any department's equipment breaks down on the lateral line, because only 1 contralateral power leads to its load can't change the confession, can only resume the power transmission after transformer substation bus overhauls the processing and accomplishes, the power supply reliability loss is very big, and probably consequently cause complaint and negative public opinion.

After the issued DL/T5729 and 2016 Power distribution network planning and design technology guide in 2016, a double-ring type cable power distribution network structure is provided, and I and II sections of buses can be selectively interconnected in a certain ring network unit according to needs. As shown in fig. 2, this method can theoretically change the disadvantage that the conventional dual-ring structure is substantially composed of two non-interconnected single-ring structures, i.e., i and ii sections of buses (i.e., first and second cables) are interconnected in the ring network unit that needs to be interconnected, but because the positions and the number of the interconnected ring network units are not determined, effective and clear guidance cannot be provided when the power distribution network structure planning design is performed. The following problems often exist in practical operation:

1. one way is to interconnect the i and ii section buses (i.e. the first and second cables) in all ring network units in a dual ring cable distribution network structure, and the excessive interconnection that results in this way can cause the following drawbacks: on one hand, the access of the interconnection cable can occupy effective intervals in the ring network unit, and the actual situation in the field is that the ring network unit on the I section bus and the II section bus (namely the first cable and the second cable) does not always have too many idle intervals for the access of the interconnection cable, so that the feasibility of the overall interconnection field implementation is not high. On one hand, based on a double-ring type cable distribution network structure between two high-voltage substations, because the number of ring network units is large, if I and II sections of buses (namely, a first cable and a second cable) in each ring network unit are interconnected, although the opposite power and transfer paths for load transfer are theoretically increased, the complexity of the cable distribution network structure is increased due to the excessive number of transfer paths, meanwhile, before the transfer is implemented, each transfer path needs to comprehensively balance multiple factors such as weather, environment, load flow, load prediction and the like to determine whether the transfer is feasible or not, therefore, when the load transfer and power supply recovery needs to be carried out immediately and rapidly in case of sudden failure or the like, the regulation and control department cannot quickly select an effective transferable path which can ensure the load bearing capacity of the line, thereby greatly reducing the load transferring work efficiency and generating extra loss of the number of households.

Meanwhile, for field operation, due to the fact that the alternative schemes of the supply transfer paths are numerous, the supply transfer operation steps and the complexity are increased, the possibility of misoperation is correspondingly generated and increased, and great potential safety hazards exist for the dispatching safety and the field safety production of the cable distribution network.

2. In addition to the above-mentioned excessive interconnection, there is another method of subjective judgment according to the experience of the control and operation and maintenance personnel, that is, subjective random interconnection. One or more ring network units are selected subjectively and randomly to interconnect I and II sections of buses (namely, a first cable and a second cable) in the ring network units. However, such interconnection has strong subjectivity, is not beneficial to the management of the network frame by a regulation and control department, and meanwhile, because of the poor subjective consideration, when the network frame is switched to the actual requirement, the switching failure is caused by the reasons that the load rate cannot be met and the like, the switching working efficiency is reduced, the normal adjustment of the operation mode of the distribution network is influenced, and the loss of the number of households is caused or enlarged when the reliability is increased.

Disclosure of Invention

In order to solve the technical problem, the invention provides a dual-ring type cable distribution network structure with limited interconnection.

A dual-ring cable distribution network structure with limited interconnection comprises a first cable, a second cable and at least two ring network units, wherein the first cable and the second cable form the dual-ring cable distribution network, the at least two ring network units are arranged on the first cable and the second cable, the interconnection cables are used in the head ring network unit and the tail ring network unit of the dual-ring cable distribution network, and the first cable and the second cable in the head ring network unit and the tail ring network unit are interconnected to increase a load switching power supply and a power supply path.

Preferably, the interconnection cable is used in the looped network unit where the open loop point of the double-loop cable distribution network is located, the first cable and the second cable in the looped network unit of the open loop point are interconnected, so that when the load transfer of the farthest end to the side power supply is performed, the loads of other lines are connected in series as little as possible in the transfer path, and the shortest transfer path of the farthest end to the side power supply is realized.

Preferably, according to actual needs, a temporary interconnection cable is added in the ring network unit which is expanded and interconnected on the basis of the limited interconnection, and the interconnection cable is connected with the first cable and the second cable by using the load switch.

Preferably, the connection point switches of the interconnection cables on the first cable and the second cable in each ring network unit are load switches, and the common operation mode of the load switches is a normally open state.

The technical scheme adopted by the invention has the following beneficial effects:

1. the interconnection cables are used in the head and tail two ring network units of the double-ring type cable distribution network, the first cables and the second cables in the head and tail two ring network units are interconnected to increase the load switching power supply transfer and supply paths, the load rate of each cable line in the double-ring type cable distribution network structure during normal operation is improved, a friendly network frame environment is provided for the development of the uninterrupted operation of the cables for load switching power supply transfer, the power supply reliability is improved, and the double-ring type cable distribution network has good social benefits and economic benefits. In addition, the invention provides a limited interconnection basic structure with definite fixed interconnection points, so that the supply transfer scheme has rules and can be followed, the supply transfer working efficiency is improved, the misoperation hidden danger caused by excessive interconnection and subjective random interconnection is reduced and avoided, and the controllable degree of the cable net rack load supply transfer work is improved;

2. the interconnection cable is used in the looped network unit where the open loop point of the double-loop cable distribution network is located, the first cable and the second cable in the looped network unit of the open loop point are interconnected, so that when the farthest end is subjected to load transfer to the side power supply, the loads of other lines are connected in series as few as possible in a transfer path, and the shortest transfer path of the farthest end to the side power supply is realized.

3. According to the practical situation, temporary interconnection cables are added in the ring network units needing to be expanded and interconnected, the interconnection cables are connected with the first cables and the second cables through load switches, and the transfer paths of the double-ring cable distribution network are further increased in a controllable range;

4. the interconnection cable is connected with the first cable and the second cable in each ring network unit through the connection point switches which are all load switches, the common operation mode of the load switches is a normally open state, switching and quitting are performed step by step according to the current direction during switching, and the orderly and safe switching of the load is ensured.

5. For a double-ring type cable distribution network consisting of two single-ring structures without interconnection points, a double-ring type cable distribution network structure with limited interconnection is adopted, and the current situation that each original line only has 1 contralateral power supply and only 1 rotatable supply path is converted into the situation that each original line has 3 contralateral power supplies and has 9 rotatable supply paths. The load factor of each cable line in the double-ring type cable distribution network structure in normal operation is improved.

The following detailed description of the present invention will be provided in conjunction with the accompanying drawings.

Drawings

The invention is further described with reference to the accompanying drawings and the detailed description below:

FIG. 1 is a schematic diagram of a conventional configuration of a single-ring cable distribution network;

fig. 2 is a schematic diagram of a conventional structure of a dual ring cable distribution network;

FIG. 3 is a schematic diagram of a dual-ring cable distribution network in DL/T5729 and 2016 Power distribution network planning and design technology guide rules in 2016;

fig. 4 is a schematic structural diagram of a dual-ring type cable distribution network after head and tail ring network units are connected by using interconnection cables;

fig. 5 is a schematic structural diagram of a dual-ring type cable distribution network open loop point ring network unit connected by using an interconnection cable;

fig. 6 is a schematic structural view of an interconnection cable of a dual ring type cable distribution network in a charging state;

fig. 7 is a schematic diagram of expanding interconnection by adding temporary interconnection cables according to actual conditions on the basis of a limited interconnection dual-ring type cable distribution network structure.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

Fig. 1 is a schematic view showing a conventional structure of a single-ring type cable distribution network, and fig. 2 is a schematic view showing a conventional structure of a double-ring type cable distribution network, in which ■ denotes an outlet switch,

a normally-closed switch is shown,

indicating a normally open switch. As shown in FIG. 2, the cable line AI is connected out from I section bus of A transformer substation, and is connected to the ring network of open loop point through I section bus in A1 ring network unit and A2 ring network unitI section generating line of unit. An incoming switch and an outgoing switch are respectively arranged on I-section buses of the A1 ring network unit and the A2 ring network unit and are in a normally closed state, the incoming switch of the I-section buses of the ring opening point ring network unit is in a normally closed state, and the outgoing switch, namely the ring opening point switch, is in a normally open state. Cable run BI is taken out by I section generating line of B transformer substation, through I section generating line to I section generating line of ring opening point looped netowrk unit in B1 looped netowrk unit and the B2 looped netowrk unit. An incoming switch and an outgoing switch are respectively arranged on the I-section buses of the B1 ring network unit and the B2 ring network unit and are in a normally closed state, and the outgoing switch of the I-section buses of the ring network unit is opened at an open ring point, namely the open ring point switch is in a normally open state. The cable line AI and the cable line BI are isolated through an open loop point switch, and the operation modes of ring network wiring and open loop operation are realized.

And the cable line AII is connected out from II sections of buses of the A transformer substation and is connected to II sections of buses of the ring network unit at the open loop point through II sections of buses in the A1 ring network unit and the A2 ring network unit. An incoming switch and an outgoing switch are respectively arranged on the A1 ring network unit and the A2 ring network unit II section buses and are in a normally closed state, the open loop point ring network unit II section bus incoming switch is in a normally closed state, and the outgoing switch, namely the open loop point switch, is in a normally open state. And the cable line BII is connected out from the second section of bus of the substation B and is connected to the second section of bus of the ring network unit at the open loop point through the second section of bus in the B1 ring network unit and the B2 ring network unit. An incoming switch and an outgoing switch are respectively arranged on the B1 ring network unit and the B2 ring network unit II section buses and are in a normally closed state, and the outgoing switch of the ring opening point ring network unit II section bus is in a normally open state. The cable line AII and the cable line BII are isolated through the ring opening point switch, and the operation modes of ring network wiring and ring opening operation are realized.

In fig. 2 the cabling ai has and only has one opposite side power supply: a bus of a section I of the B transformer substation is only provided with one transfer path: namely, a bus-cable line B I of a section I of the substation B; the first section of bus of the transformer substation A and the first section of bus of the transformer substation B are mutually opposite sides and can be used for supplying power; cable run aii has and only has one opposite side power supply: b, only one transfer path of the second section of bus of the substation is provided: namely a second section bus of the substation B, namely a cable line BII; and the second section of bus of the A transformer substation and the second section of bus of the B transformer substation are mutually opposite rotatable power supplies.

When I section generating line of A transformer substation is because of the troubleshooting, for guaranteeing to last load continuation power supply on cable run AI, will carry out the switching with cable run AI and change the confession, by the offside power: and the I section of bus of the B transformer substation is supplied, the open loop point switch is closed after the two sides of the open loop point switch are faultless due to the fact that the open loop point switch is opened on the I section of bus in the open loop point ring network unit, the outlet switch of the cable line AI is pulled open, and finally the cable line AI and the cable line BI are all supplied with power by the I section of bus of the B transformer substation. Similarly, when I section bus of B transformer substation, II section buses of A transformer substation, II section buses of B transformer substation because of the troubleshooting, also need the offside power supply to two cable run simultaneously, consequently be in every cable run on above-mentioned double ring structure cable distribution network when daily the operation, all need be separately for the maximum load capacity allowance that offside circuit shifted when stopping operation because of the accident. Generally, taking fig. 2 as an example, the sum of the loads on cable line ai and cable line bi is equal to the rated total load that can be carried by the section of cable between the first section bus of the a substation and the first section bus of the B substation.

FIG. 3 is a schematic diagram of a double-ring cable distribution network in the design rule of distribution network planning technology (DL/T5729) -2016 (2016). As shown in fig. 3, between the first section and the second section of buses in each ring network unit, the interconnection cables which can be communicated are indicated by dashed lines, but the positions and the number of fixed interconnection points are not explicitly shown, and the practical work is not taught.

Fig. 4 is a schematic structural diagram of a dual-ring type cable distribution network after head and tail ring network units are connected by using interconnection cables. As shown in fig. 4, between the first-stage and second-stage buses of the a-substation and the second-stage buses of the B-substation, the head and tail ends of a common conventional double-ring type cable distribution network in a ring network connection and open-loop operation mode, that is, the a1 ring network unit and the B1 ring network unit, use existing load switches in a space interval and an interval, and use engineering cables to permanently lay interconnection cables 1 and 2. The interconnection cable 1 and the interconnection cable 2 are connected with switches of I-section and II-section buses in the ring network unit and are load switches, and meanwhile the load switches are in a normally open state.

Through laying interconnection cable 1, interconnection cable 2 forever, make any cable run of AI, AII, BI, BII, BIII from only 1 offside power on the basis of figure 1, increase for 3 offside power that can carry out the load and change the confession.

Fig. 5 is a schematic structural diagram of a dual-ring type cable distribution network open loop point ring network unit connected by using an interconnection cable. After the permanent laying and connection of the interconnection cables 1 and 2 shown in fig. 3 are completed, the interconnection cable 3 is permanently laid and connected in the open loop point ring network unit by using the engineering cable. The interconnection cable 3 is connected with the I section and the II section of the bus switch and is a load switch which is in a normally open state.

Due to the fact that interconnection is carried out in the ring-opening point ring network unit, when the farthest end side power supply carries out load transfer, the farthest end side power supply can be guaranteed to be connected with other line loads in series as few as possible on a transfer path, the shortest transfer path of the farthest end side power supply is achieved, and the load rates of the A I, the A II, the B I and the B II in normal operation states are improved.

Taking the case that the load on the cable line ai in fig. 5 is transferred by the second segment bus of the B substation on the diagonal line farthest from the load as an example: if no open loop point interconnection cable exists, two switching paths are provided, one path is a cable line BII-cable line AII, the cable line BII needs to increase and bear the total load on the cable line AII and the cable line AII, namely the second section of bus of the substation B bears the load on 8 ring network units.

The other path is a cable line BII, a cable line BII and a cable line AI, the cable line BII is required to bear the total load on the cable line BII and the cable line AI, namely the second section of bus of the substation B bears the load on 7 ring network units in total.

When the interconnected cable is used for switching supply at the open loop point, the switching supply path is a cable line BII-cable line AI, and at the moment, the cable line BII only needs to increase and bear the load of the looped network unit at the open loop point and the total load on the cable line AI, namely, the second section of bus of the substation B bears the load on 6 looped network units in total.

By permanently laying the interconnection cable 3, when any cable line of AI, BI and BI is overhauled in the bus of the upper-stage transformer station due to fault, any opposite-side power supply can be selected, and load transfer is carried out by selecting a shortest and optimal transfer path. Compared with a common conventional double-ring cable distribution network consisting of two single-ring structures without interconnection points, the double-ring cable distribution network has the advantages that each original line is converted into a double-ring cable distribution network, wherein each original line only has 1 contralateral power supply and only has 1 transferable supply path, each original line has 3 contralateral power supplies, and the double-ring cable distribution network is provided with 9 transferable supply paths.

After the interconnection cable shown in fig. 4 and 5 is laid, taking the case that the load on the cable line ai needs to be transferred, the number of the opposite side power supplies is 3 (i.e. the second-section bus of the a substation, the first-section bus of the B substation and the second-section bus of the B substation), and on the premise that the transfer is performed only by one opposite side line, i.e. on the premise that the load on the transfer line is increased as much as possible, the following 4 paths are provided:

A. after the nuclear phase at the two sides of the open loop point switch in the normally open state in the open loop point ring network unit is correct, the open loop point switch is closed; and then, a first-section bus incoming switch in the A1 ring network unit is pulled (or a first-section bus outlet switch of the A transformer substation is pulled). At this time, the load on the cable line AI is transferred to be borne by the cable line BI.

B. Closing a load switch in a normally open state between the II-section bus in the A1 looped network unit and the interconnection cable 1; after the two sides of the load switch in a normally open state between the I-section bus and the interconnection cable 1 in the A1 looped network unit are faultless, closing the load switch; and then, a first-section bus incoming switch in the A1 ring network unit is pulled (or a first-section bus outlet switch of the A transformer substation is pulled). The load on the cable line ai is now transferred to be borne by the cable line aii.

C. Closing a load switch in a normally open state between the second section of bus in the ring-opening point looped network unit and the interconnection cable 3; after the two sides of the load switch in a normally open state between the I section of bus and the interconnection cable 3 in the open loop point ring network unit are faultless, closing the load switch; and then, a first-section bus incoming switch in the A1 ring network unit is pulled (or a first-section bus outlet switch of the A transformer substation is pulled). The load on the cable line ai is now transferred to be borne by the cable line aii.

D. After the phases are checked to be correct at two sides of a II-section bus outgoing switch (open-loop point switch) in the open-loop point ring network unit, the switch is closed; then, pulling open the incoming line switch of the second section of bus in the ring point ring network unit; closing a load switch in a normally open state between the second section of bus in the ring-opening point looped network unit and the interconnection cable 3; after the phases on two sides of the load switch in a normally open state between the I section of bus and the interconnection cable 3 in the open loop point ring network unit are correct, closing the load switch; and then, pulling open the I section of bus incoming switch in the A1 looped network unit (or pulling open the I section of bus outlet switch of the A transformer substation), and at the moment, the load on the cable line AI is transferred to be borne by the cable line BI.

In order to avoid the function incapability caused by insulation damage, condensation, dirt accumulation and the like which possibly occur when the interconnection cable is in a non-power-on state for a long time, the interconnection cable cannot be normally put into operation immediately when power supply needs to be transferred to cause power supply failure, the load switch of the interconnection cable on the bus on one side of the ring network unit can be changed into a normally-on state, as shown in fig. 6, the interconnection cable is in a charging ring network waiting state for a long time, and when sudden failure needs to be transferred to power supply urgently, the interconnection cable can be timely and rapidly put into operation to transfer the load to power supply.

The ring combining, ring releasing, ring opening and closing operations all adopt a hot-fall mode, namely, the user does not have power failure in the whole process. When the bypass flexible CABLE is used as an interconnection CABLE, a French NESANS BY PASS CABLE flexible CABLE can be adopted, the rated voltage of the flexible CABLE is 10kV, and the maximum current-carrying capacity can reach 898A.

On the basis of a limited interconnection double-ring type cable distribution network structure, a temporary interconnection cable is added in a ring network unit needing to be expanded and interconnected according to actual conditions, and a load switch and the interconnection cable are used for connecting I sections of buses and II sections of buses. The load switches are all in the off-position or at least the off-position of the load switch of the bus at one side is reserved according to the requirement.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that the invention is not limited thereto, and may be embodied in other forms without departing from the spirit or essential characteristics thereof. Any modification which does not depart from the functional and structural principles of the present invention is intended to be included within the scope of the claims.

Claims

1. A dual-ring cable distribution network structure with limited interconnection comprises a first cable, a second cable and at least four ring network units, wherein the first cable and the second cable form the dual-ring cable distribution network, and the at least four ring network units are arranged on the first cable and the second cable;

the interconnection cable is used in the looped network unit where the open loop point of the double-loop cable distribution network is located, the first cable and the second cable in the looped network unit of the open loop point are interconnected to reduce the line load of access, so that when the farthest end is subjected to load transfer to the side power supply, the farthest end is guaranteed to be connected with other line loads in series as little as possible in the transfer path, and the shortest transfer path of the farthest end to the side power supply is realized.

2. The limited interconnection double-ring type cable distribution network structure according to claim 1, wherein temporary interconnection cables are added in the ring network units needing to be expanded and interconnected according to actual conditions, and the interconnection cables are connected with the first cables and the second cables by using load switches.

3. A limited interconnection dual ring type cable distribution network structure according to claim 1 or 2, wherein the connection point switches of the interconnection cables on the first cable and the second cable in each ring network unit are load switches, and the normal operation mode of the load switches is a normally open state.