CN217642735U

CN217642735U - System for realizing three-phase balance of transformer area based on distributed active unbalance compensation device

Info

Publication number: CN217642735U
Application number: CN202221478318.7U
Authority: CN
Inventors: 康凯; 梁琰哲; 胡辰旭; 李东明
Original assignee: State Grid Shuozhou Power Supply Co
Current assignee: State Grid Shuozhou Power Supply Co
Priority date: 2022-06-14
Filing date: 2022-06-14
Publication date: 2022-10-21
Anticipated expiration: 2032-06-14

Abstract

The utility model provides a system for realizing three-phase balance in a platform area based on a distributed active unbalance compensation device, which belongs to the technical field of three-phase unbalance compensation; the technical problem to be solved is as follows: the improvement of a system hardware structure for realizing three-phase balance of a transformer area based on a distributed active unbalance compensation device is provided; the technical scheme is as follows: the system comprises an AUC host arranged on a trunk line of an outgoing line of a transformer substation in a transformer area and a plurality of AUC extensions arranged at a user end of the transformer area, wherein the AUC host and the AUC extensions are connected in parallel to a power grid, and the AUC host and the AUC extensions form a network through LORA (Long-range architecture) for communication; the AUC host and the AUC slave comprise a shell, a display screen is arranged on the front face of the shell, an AUC controller is arranged in the shell, and the AUC controller is connected with the LORA module through a lead; each AUC host and AUC slave installation position is provided with a current transformer which is connected with a correspondingly installed AUC controller through a lead; the utility model discloses be applied to the unbalanced three-phase of platform district and administer.

Description

System for realizing three-phase balance of transformer area based on distributed active unbalance compensation device

Technical Field

The utility model provides a system based on distributed active unbalance compensation device realizes platform district three-phase balance belongs to platform district three-phase balance technical field.

Background

At present, the problem of three-phase imbalance of a low-voltage distribution network is common, and the problems of high loss, multiple defects, poor reliability and the like seriously threaten the safe operation of the power grid. The three-phase unbalanced load has influence on the power system and the power supply of users, and is mainly represented in the following aspects:

(1) Zero-sequence current generated by unbalanced three-phase current can cause loss to a neutral line, the neutral line generates voltage drop to cause neutral drift, when the three-phase voltage changes, one-phase voltage of a load is reduced, and the voltage is increased if the three-phase voltage is light, and the overvoltage can generate adverse effect on the safe operation of electric equipment;

(2) When the unbalanced three-phase current is in each stage that the actual output of the distribution transformer is reduced and the rated capacity is limited with the changeable maximum allowable output, the excessive capacity exists under the condition of the unbalanced three-phase load of the distribution transformer, and the load is light, so that the actual output of the distribution transformer is reduced;

(3) The three-phase current is unbalanced, and zero-sequence magnetic flux can be generated in the iron core of the distribution transformer. Because the high-voltage side angle connection mode of the transformer does not have a zero sequence current channel, the steel member and the oil tank wall are used as channels, but the effect of the steel member is not ideal, hysteresis and eddy current loss can be generated when the zero sequence current passes through the steel member, the temperature of the steel member is increased, the generated high temperature can accelerate the aging of the winding insulation of the transformer, and the service life of the transformer is greatly shortened.

The method mainly adopted for treating and managing the three-phase imbalance at present comprises manual phase modulation and phase change switch installation, and the main problems of the method are as follows: the manual phase modulation has poor real-time performance, because of random change of the load, the manual phase modulation cannot realize real-time treatment, only can solve the unbalance in a short time, and the manual phase modulation has large adjustment randomness on the load of a user and only can realize rough adjustment. The phase change switch has the defects of low real-time performance, incapability of frequent adjustment and the like, and mainly realizes the balance of the front end of the main line.

Therefore, the utility model provides a handle low pressure through distributing type active unbalance compensation arrangement (distributing type AUC) and join in marriage net unbalanced three phase, solve power supply enterprise low pressure fortune dimension personnel not enough, the untimely difficult problem is handled to low pressure fortune dimension means, improves fortune dimension personnel's work efficiency and quality, improves the low pressure and joins in marriage net electric energy quality.

SUMMERY OF THE UTILITY MODEL

The utility model discloses an overcome not enough that exists among the prior art, the technical problem that will solve is: the improvement of a system hardware structure for realizing three-phase balance of a platform area based on a distributed active unbalance compensation device is provided.

In order to solve the technical problem, the utility model discloses a technical scheme be: the system comprises an AUC host arranged on an outgoing trunk line of a transformer substation in the transformer substation of the transformer substation and a plurality of AUC extensions arranged at user terminals of the transformer substation, wherein the AUC host and the AUC extensions are connected in parallel to a power grid, and the AUC host and the AUC extensions form a network through LORA (Long term evolution architecture) for communication;

the AUC host and the AUC slave comprise a shell, a display screen is arranged on the front face of the shell, an AUC controller is arranged in the shell, and the AUC controller is connected with the LORA module through a lead;

and each AUC host and AUC slave are provided with a current transformer, and the current transformers are connected with the corresponding AUC controllers through wires.

The AUC controller is also connected with the Bluetooth module through a lead.

And the AUC controller is also connected with the RS485 module through a lead.

And the AUC host is arranged on a low-voltage side outlet of the transformer.

The AUC controller is a single chip microcomputer or a PLC controller.

The utility model discloses beneficial effect for prior art possesses does: the utility model provides a system based on balanced distributed active unbalance compensation arrangement realizes platform district three-phase is through the balanced system current of distributed active unbalance compensation arrangement (distributed AUC) through external current transformer real-time supervision, and carry out the processing analysis to system current information through inside AUC controller, whether in the unbalanced three-phase state with the judgement system, negative sequence and the zero sequence current of required compensation when calculating simultaneously and reaching balanced state, then give inside IGBT and drive its action with the signal, the unbalanced current that compensation load needs, reach the compensation purpose, thereby effectively solve the unbalanced three-phase of platform district.

Drawings

The present invention will be further explained with reference to the accompanying drawings:

fig. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic diagram of the distributed AUC implementation of imbalance compensation according to the present invention;

fig. 3 is a diagram of the distributed AUC arrangement in embodiment 1 of the present invention;

fig. 4 is a diagram of the distributed AUC arrangement in embodiment 2 of the present invention;

FIG. 5 is a schematic diagram of the calculation of line loss for three phase imbalance;

fig. 6 is a schematic diagram of the calculation of the line loss when the present invention is used for balancing.

Detailed Description

As shown in fig. 1 to fig. 6, the utility model discloses a distributed AUC adopts the form of a owner from many, and owner, from the machine hardware all the same, can artificially set up that of the trunk line as the host computer through cell-phone bluetooth APP after the installation can. All the distributed AUCs are installed in parallel to the power grid, only 1 slave machine is needed to be installed on a main trunk line, and other slave machines select branches with more users and three-phase power to be installed on a telegraph pole, so that the installation position is not greatly required and is shown in figure 1.

The utility model discloses a distributed AUC administers including 2 aspects to platform district unbalanced three phase, is local compensation on the one hand, is the networking function on the one hand. And realizing the optimal compensation of the station area unbalance by the function combination of the aspect 2. The following is a description on the 2-way.

1. Local compensation

The principle of local compensation is the same as the principle of centralized AUC, load current is monitored in real time through an external Current Transformer (CT), load current information is processed and analyzed through an internal controller, reactive and unbalanced currents required to be compensated are calculated, and then control signals are sent to an internal IGBT to act, so that compensation current required by a load is sent out. The distributed AUC can compensate for reactive current and also for unbalanced current. The principle of unbalance compensation is shown in fig. 2, wherein load current A, B, C is 50, 60 and 70a respectively, three-phase average current is calculated as 60A by AUC, and 10A current of C phase is transferred to a phase by AUC during compensation, namely three-phase balance is realized. The compensation process is real-time calculation and real-time compensation, and the compensation response time is 10ms; the maximum compensation current of the single phase in the distributed AUC is 15A, namely, the current of one phase 15A can be maximally transferred to the other two phases.

2. Networking functionality

In an ideal situation, if 1 or several distributed AUCs are installed in each branch of the platform area, after all the branches of the platform area are balanced, the transformer and the main line of the platform area are naturally also balanced in three phases. However, in the actual use process, the station area has many branches, and it is impossible to install a distributed AUC for each branch, and in this case, a networking function using the distributed AUC is required.

The networking function is an AUC host, and a plurality of AUC slave machines are controlled through LORA communication; the compensation mode of the slave computer can be controlled by adjusting one parameter at the master computer, and the balance between the transformer and the main line or the balance between the branches can be preferentially ensured.

For example, a block, has 3 branches:

the currents of the first branch A, B, C are 0, 15, 30A, 15 and 15 respectively;

the current of the B branch A, B, C is 30, 15 and 0A respectively. 22.5, 15, 7.5;

the current of the third branch A, B, C is 0, 45 and 90A respectively. 15. 45, 75;

if 1 distributed AUC is installed in each of the 3 branches, then 1 distributed AUC is installed in the main trunk, and 4 branches are provided in total, if there is no networking function, the first branch and the second branch can be compensated for balance, while the third branch has a larger unbalanced current, which cannot compensate balance, and the transformer is still unbalanced. If the networking function is started, the host computer finds that the second branch is not compensated, but the balance of the transformer and the main line is facilitated, and at the moment, the host computer can control the AUC of the second branch to be not compensated or to reduce the compensation current so as to preferentially ensure the balance of the transformer. Therefore, the balance of the main line is preferentially ensured, the equipment output is reduced, and the loss is reduced.

The utility model discloses after confirming the distributed AUC quantity that the platform district needs, when selecting the mounted position, follow following step:

1. the method comprises the steps of obtaining a platform area topology, obtaining the platform area topology through a GIS system, a PMS system and the like, and manually drawing the platform area topology during field installation.

2. The main machine is suggested to be arranged on the main line, namely, a mutual inductor of the main machine is ensured to be sleeved on the main line of the distribution room, the current of the whole distribution room is measured, and the main machine can obtain the effect of each slave machine after treatment.

3. The method comprises the steps of obtaining a single user with large power consumption (the power consumption ratio exceeds 1/10 of the power consumption ratio of the single user) in a power distribution area, wherein three-phase imbalance of the power distribution area can be caused by the single user, so that the user is mainly treated, and a distributed AUC slave machine is recommended to be additionally arranged at the three-phase power position closest to the front end of the user.

4. And selecting the positions of the slave machines of the rest distributed AUC, preferentially selecting branches with more users (analyzing the number of users of each branch according to the platform area topology, and comparing the number of the selected users), and recommending that 1 slave machine of the distributed AUC is installed every 30-50 users.

In the installation position selection process, the determination of all distributed AUC installation positions is simulated through the acquired distribution area topology, and then actual field installation is carried out. During actual field installation, the selected distributed AUC installation position cannot be normally installed due to the installation environment position, and the station area topological graph is recommended to be carried, and the installation position is reselected nearby for installation. This can be understood with reference to the example of a distributed installation.

Example 1

The station area has no large users, the host is installed in the trunk line, the slave selects the branch installation with a large number of users, and the point selection is schematically shown in fig. 3:

taking fig. 3 as an example, 1 slave is installed in each of 3 branches (31, 27, and 50) with a large number of users, and 1 # slave is installed in the branch collection point, considering that only 1 branch of 50 branches may have insufficient AUC capacity, and 6 branches of nearby branches may not have equipment compensation. The host is installed on the main trunk line, and can be globally scheduled, and can complete compensation for (19 +3+ 6) users at the upper end of the branch of 31 users.

Example 2

When a large user exists in the platform area, besides the branches with more users, 1 or more distributed AUCs are also needed to be installed in the branches with the large user. The point selection is schematically shown in FIG. 4:

in fig. 4, 1 distributed AUC (slave 5 #) is installed in a branch having a large number of users in addition to branches having many users, and only 1 AUC is installed in branches having 9 and 15 users, so that 1 slave 4# may be installed in a summary location.

The utility model discloses a distributing type AUC also has certain promotion effect to terminal low-voltage of platform district, line loss qualification rate with the unbalanced treatment back of branch, trunk.

1. Line loss reduction

As shown in fig. 5 and 6, the line loss is much lower in the three-phase balance than in the three-phase unbalance, but since the distributed AUC itself has a partial loss (about 2% of the compensation capacity (non-rated capacity)), the loss reduction effect may not be significant in the actual operation.

2. Boosting low voltage

Under the condition that the line impedance is fixed, the larger the line current is, the larger the line voltage drop (U = I R) is, the lower the voltage to the tail end of the line is, if the unbalance is treated, the current of one phase with large current is reduced, the line voltage drop is reduced, and the low voltage at the tail end of the line is also improved.

The utility model discloses a distributed AUC's parameter is as shown in following table 1:

table 1 distributed AUC parameters.

About the utility model discloses what the concrete structure need explain, the utility model discloses a each part module connection relation each other is definite, realizable, except that the special explanation in the embodiment, its specific connection relation can bring corresponding technological effect to based on do not rely on under the prerequisite of corresponding software program execution, solve the utility model provides a technical problem, the utility model provides a model, the connection mode of parts, module, specific components and parts that appear all belong to the prior art such as the published patent that technical staff can acquire before the application day, published journal paper, or common general knowledge, need not to describe in detail for the technical scheme that the present case provided is clear, complete, realizable, and can be according to this technical means or obtain corresponding entity product.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. System based on distributed active unbalance compensation device realizes platform district three-phase balance, its characterized in that: the system comprises an AUC host arranged on an outgoing trunk line of a transformer substation in a transformer area and a plurality of AUC extensions arranged at user terminals of the transformer area, wherein the AUC host and the AUC extensions are connected in parallel to a power grid, and the AUC host and the AUC extensions form a networking for communication through LORA;

each AUC host and AUC slave installation position is provided with a current transformer, and the current transformers are connected with the AUC controllers correspondingly installed through wires.

2. The system for realizing three-phase balance of the platform area based on the distributed active unbalance compensation device according to claim 1, wherein: the AUC controller is also connected with the Bluetooth module through a lead.

3. The system for realizing three-phase balance of the platform area based on the distributed active unbalance compensation device according to claim 2, wherein: and the AUC controller is also connected with the RS485 module through a lead.

4. The system for realizing three-phase balance of the platform area based on the distributed active unbalance compensation device according to claim 1, wherein: and the AUC host is arranged on a low-voltage side outlet of the transformer.

5. The system for realizing three-phase balance of the platform area based on the distributed active unbalance compensation device according to claim 1, wherein: the AUC controller is a single chip microcomputer or a PLC controller.