CN113541197A

CN113541197A - Energy control method and system for low-voltage transformer area flexible-direct interconnection energy-storage-free system

Info

Publication number: CN113541197A
Application number: CN202110661554.6A
Authority: CN
Inventors: 季宇; 熊雄; 徐旖旎; 邵瑶; 张海; 吴鸣; 刘海涛
Original assignee: China Online Shanghai Energy Internet Research Institute Co ltd
Current assignee: China Online Shanghai Energy Internet Research Institute Co ltd
Priority date: 2021-06-15
Filing date: 2021-06-15
Publication date: 2021-10-22

Abstract

The invention relates to an energy control method and system for a low-voltage transformer area flexible-straight interconnection energy-free system, which comprises the following steps: classifying the transformer areas; when no fault station area exists and the net power of the direct current side is positive, determining non-fault station areas, calculating the residual active margin of each non-fault station area, and determining an active margin array of the non-fault station areas; executing load power distribution at a direct current side, and determining a first power fixed value of a converter of a transformer area in a non-fault transformer area array; updating the active load of each station area, calculating the load rate of each station area, and re-determining a normal station area and a heavy load station area; calculating the active compensation allowance of each normal station area and the active compensation demand of the heavy-load station area, and determining an allowance array and a demand array; determining that an active power compensation demand array of a fault transformer area is added into the demand array; updating the current converter margin of each transformer area; and determining a second power fixed value of the converter of each transformer area according to the demand array, the margin array and the converter margin, and sending a control instruction to the corresponding converter.

Description

Energy control method and system for low-voltage transformer area flexible-direct interconnection energy-storage-free system

Technical Field

The invention relates to the technical field of voltage alternating current and direct current hybrid power distribution, in particular to an energy control method and system of a low-voltage transformer area flexible-direct interconnection energy-free system.

Background

The power distribution station area is one of the important components of the power system, and directly influences the local economic development and the daily life quality of users. Most of the existing low-voltage transformer areas adopt a single transformer and single line power supply mode, the reliability is low, power supply among the transformer areas is independent, and unified management and control are lacked. In rural areas, along with the construction of beautiful villages and the promotion of the electrification engineering of villages made by governments, the access public capacity is opened and increased, the requirements of subordinate users in the transformer areas on the power supply reliability are increased day by day, and the original single power supply is difficult to meet the requirements of increasing power utilization capacity and high reliability. In addition, seasonal load fluctuation often occurs in the same district due to different economic structures, so that the problem of large difference of the load rate of the district is caused, and if the problem is solved by increasing the distribution points blindly, the residual capacity of the district with light load in the district is still not fully utilized. And with the increasing direct current loads of electric vehicle charging stations, data centers, direct current household appliances, communication equipment and the like and the high-proportion and high-capacity decentralized access of direct current distributed power sources such as photovoltaic power sources and the like, the current distribution network source-load-storage direct current characteristics become more obvious. The access of the direct-current distributed power supply and the load increases the conversion link and grid-connection difficulty of a power grid, directly influences the power quality and operation control of the existing power distribution station area, and reduces the overall operation efficiency of the system. The access positions and the capacities of residential photovoltaic and large-scale photovoltaic in partial transformer areas are not controllable, the electric energy quality and power fluctuation can be influenced, and if the problem of consumption of high-permeability photovoltaic cannot be solved, the electric quantity is caused to be transmitted reversely. In addition, the problem of insufficient capacity of a power distribution area and a part of power lines is caused by the disordered access of the large-scale electric automobile, and a large amount of capital needs to be invested for capacity increase and expansion.

Therefore, a new energy control method is needed for the challenges that the power supply capacity of a low-voltage alternating-current distribution network needs to be improved urgently and the power supply quality needs to be improved urgently.

Disclosure of Invention

The invention provides an energy control method and system of a low-voltage transformer area flexible-direct interconnection energy-free system, and aims to solve the problem of how to realize transformer area load balancing.

In order to solve the above problem, according to an aspect of the present invention, there is provided an energy control method for a low-voltage transformer area soft and straight interconnected non-energy storage system, the method including:

step 1, classifying the distribution areas in the system;

step 2, when no fault station area exists in the system and the collected direct current side net power is positive, directly determining a non-fault station area, calculating the residual active margin of each non-fault station area, and sequencing according to the size of the residual active margin of each non-fault station area to determine an active margin array of the non-fault station area;

step 3, performing direct-current side load power distribution according to the sequence of the residual active margins of the transformer areas in the non-fault transformer area active margin array to determine a first power fixed value of a current converter of the transformer areas in the non-fault transformer area array;

step 4, updating the active load of each area in the system, calculating the load rate of each area according to the updated active load, and re-determining a normal area and a heavy load area according to the updated load rate of the areas;

step 5, calculating the active compensation allowance of each normal station area and the active compensation demand of each heavy load station area according to the updated normal station area and the updated heavy load station area, sequencing according to the active compensation allowance of each normal station area to determine an allowance array, and sequencing according to the active compensation demand of each heavy load station area to determine a demand array;

step 6, determining that the active compensation demand of the fault station area is equal to the active load, determining an active compensation demand array of the fault station area according to the active compensation demand of each station area with the type of the fault station area, adding the active compensation demand array of the fault station area into the demand array, and arranging the active compensation demand array of the fault station area in the front to update the demand array;

step 7, updating the current converter margin of each transformer area in the system;

and 8, determining a second power fixed value of the converter of each zone according to the demand array, the margin array and the current converter margin of each zone, and sending a control instruction to the corresponding converter according to the second power fixed value of the converter of each zone so that the converter of each zone outputs power according to the corresponding second power fixed value.

Preferably, wherein said classifying the zones within the system comprises:

if the converter in the transformer area operates in a V-f mode, determining the converter area as a fault transformer area;

if the converter in the transformer area does not operate in the V-f mode and the load rate of the transformer area is smaller than the load rate limit value, determining that the transformer area is a normal transformer area;

and if the converter in the transformer area does not operate in the V-f mode and the load rate of the transformer area is greater than or equal to the load rate limit value, determining the transformer area as a heavy-load transformer area.

Preferably, the performing, according to the sequence of the remaining active margins of the cells in the non-faulty cell array, load power distribution on the dc side to determine a first power fixed value of a converter of a cell in the non-faulty cell array includes:

s11, initializing the number N1 of the transformer areas in the non-fault transformer area array with S equal to 1 and S equal to or less than;

s12, selecting the minimum value of the residual active margin of the S-th station area and the allowable capacity of the corresponding converter as the residual active margin of the i-th station area;

s13, judging whether the residual active margin of the S-th station area meets the requirement that the residual active margin is less than or equal to the current net power at the direct current side; wherein,

if the current net power of the converter is not satisfied, providing power according to the load requirement of the direct current side, determining that the first power fixed value of the converter of the s-th non-fault area is the current net power of the direct current side, and updating the current net power of the direct current side to be 0;

if the difference is met, determining that the allowance is insufficient, providing according to the maximum allowance, determining that a first power fixed value of a current converter of an s-th non-fault station zone is the residual active allowance of the s-th station zone, updating the direct-current side net power to be the difference between the current direct-current side net power and the active load of the s-th station zone, and updating s to be s + 1;

s14, if the current net power at the direct current side is 0 or S is more than N1, directly entering the step 4; otherwise, the process proceeds to step S12.

Preferably, wherein the method further comprises:

when a fault area exists in the system, the load rate limit values of all areas are improved to be the load rate limit values under the fault condition, and sequencing is carried out according to the active load of the area before the fault so as to determine a fault area active load array;

when the collected net power of the direct current side is negative, determining a non-fault area according to the collected converter operation mode, sequencing according to the actual active load of the non-fault area to determine a non-fault area active load array, and constructing an area active load array according to the fault area active load array and the non-fault area active load array; the active load array of the fault area is in front, and the active load array of the non-fault area is behind.

Preferably, wherein the method further comprises:

according to the active load sequence of the transformer area in the active load array, performing direct current side load power distribution to determine a third power fixed value of a converter of the transformer area in the active load array, including:

s21, initializing the number N2 of the transformer areas in the active load array, wherein j is equal to 1 and j is equal to or less than the number N2;

s22, selecting the minimum value of the active load of the jth station area and the allowable capacity of the corresponding converter as the active load of the jth station area;

s23, judging whether the active load of the jth station area meets the absolute value of the current direct current side net power or not; wherein,

if the current net power of the direct current side is not satisfied, safely and completely absorbing the direct current side power when the load is redundant, determining that a third power fixed value of the current converter of the jth station area is the current net power of the direct current side, and updating the current net power of the direct current side to be 0;

if yes, determining that the load is insufficient, determining that a third power fixed value of a current converter of a jth station area is an active load of the jth station area according to the maximum load consumption direct-current side power, updating the absolute value of the direct-current side net power to be a difference value between the absolute value of the current direct-current side net power and the active load of the jth station area, and updating j to j + 1;

s24, if the current net power of the direct current side is 0 or j is more than N2, directly entering the step 4; otherwise, the process proceeds to step S22.

Preferably, the method updates the active load of each station zone in the system by using the following modes:

P_load(i)＝P′_load(i)+P_set(i)，

the method comprises the following steps of calculating the load rate of each distribution area according to the updated active load by the following modes:

wherein, lf (i) is the load factor of the ith station zone; p_load(i) The updated active load of the ith platform area; q_load(i) The reactive load of i transformer areas; (i) rated capacity of the ith station area;P′_load(i) the actual active load of the ith platform area; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained.

Preferably, the updating the converter margin of each station zone in the system includes:

for a non-fault area, considering the forward margin of the converter, the rectifying direction is as follows:

P_per(i)＝P′_per(i)-P_set(i)，

for the first fault area, considering the reverse margin of the converter, the inversion direction is as follows:

P_per(i)＝P′_per(i)+P_set(i)，

wherein, P_per(i) And P'_per(i) Margins of the current converter of the ith transformer area after updating and before updating are respectively reserved; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained.

Preferably, the calculating an active compensation allowance of each normal distribution area and an active compensation demand of each heavy loading distribution area according to the updated normal distribution area and heavy loading distribution area includes:

wherein, P_dr(i) The active compensation allowance is the active compensation allowance when the ith station zone is a normal station zone; (i) rated capacity of the ith station area; lf lim (i) is the load rate limit value of the normal operation of the ith platform area; q_load(i) The reactive load of i transformer areas; p_load(i) The updated active load of the ith platform area; ep (i) is the active buffering interval for the ith station zone; p_dn(i) And the required active power compensation quantity is the required active power compensation quantity when the ith station area is the heavy station area.

Preferably, the determining a second power fixed value of the converter of each block according to the demand array, the margin array and the current converter margin of each block comprises:

s31, initializing h to 1, t to 1, h is less than or equal to the number N3 of the transformer areas in the demand array, and t is less than or equal to the number N4 of the transformer areas in the margin array;

s32, selecting the minimum value of the active compensation demand of the h-th transformer area and the allowable capacity of the corresponding converter as the active compensation demand of the h-th transformer area;

s33, selecting the active compensation allowance of the t-th station zone and the minimum value of the allowed capacity of the corresponding converter as the active compensation allowance of the t-th station zone;

s34, judging whether the active compensation allowance of the tth station zone meets the active compensation demand less than or equal to the h station zone; wherein,

if not, converting the supplied power according to the requirement of the heavy load transformer area, determining a second power fixed value of the current converter of the h-th transformer area as a difference value between the current power fixed value and the active compensation demand of the h-th transformer area, determining a second power fixed value of the current converter of the t-th transformer area as the sum of the current power fixed value and the active compensation demand of the current converter of the h-th transformer area, updating the power fixed value as the current second power fixed value of the corresponding transformer area, updating h to h +1, and entering the step S35;

if the current value meets the requirement, determining that the margin is insufficient, determining that a second power fixed value of the current converter of the h-th station area is a difference value between the current power fixed value and an active compensation margin of the t-th station area according to the maximum margin exclusive supply, determining that the second power fixed value of the current converter of the t-th station area is the sum of the current power fixed value and the active compensation margin of the t-th station area, updating the active compensation demand of the h-th station area to be a difference value between the current active compensation demand of the h-th station area and the active compensation margin of the t-th station area, updating the power fixed value to be the current second power fixed value of the corresponding station area, and directly entering the step S36;

s35, if h is more than N3, directly ending the circulation; otherwise, the process proceeds to step S32.

S36, if t is N4, ending the loop; otherwise, t +1 is updated, and when t ≦ N4, the routine proceeds to step S33, and when t > N4, the loop ends directly.

Preferably, wherein the method further comprises:

acquiring the state of the current converter in real time, and if the current converter is in a shutdown state, adjusting the allowable capacity of the current converter to be 0; if the converter is in a constant direct-current voltage UdcQ operation mode, the allowable capacity of the converter is adjusted to be as follows: p'_per(i)＝P_per(i)-P_ep，i＝i_udcq(ii) a Wherein, P'_per(i) Is the adjusted allowable capacity; p_per(i) The capacity of the converter is the original allowable capacity; p_epThe current is a preset active buffering margin; i.e. i_udcqThe converters operating in UdcQ mode are numbered.

According to another aspect of the present invention, there is provided an energy control system for a low-voltage transformer area soft-straight interconnected non-energy storage system, the system comprising:

the transformer area classification unit is used for classifying transformer areas in the system;

the non-fault station area array determining unit is used for directly determining a non-fault station area when no fault station area exists in the system and the collected direct-current side net power is positive, calculating the residual active margin of each non-fault station area, and sequencing according to the residual active margin of each non-fault station area to determine a non-fault station area active margin array;

the first power fixed value determining unit is used for executing direct-current side load power distribution according to the sequence of the residual active margin values of the transformer areas in the non-fault transformer area active margin value array so as to determine a first power fixed value of a converter of the transformer areas in the non-fault transformer area array;

the load rate calculation unit is used for updating the active load of each station area in the system, calculating the load rate of each station area according to the updated active load, and re-determining a normal station area and a heavy load station area according to the updated load rate of the station area;

the margin and demand array determining unit is used for calculating the active compensation margin of each normal station area and the active compensation demand of each heavy load station area according to the updated normal station area and the updated heavy load station area, sequencing the margin and demand array according to the active compensation margin of each normal station area to determine a margin array, and sequencing the margin and demand array according to the active compensation demand of each heavy load station area to determine a demand array;

the demand array updating unit is used for determining that the active compensation demand of the fault station area is equal to the active load, determining the active compensation demand array of the fault station area according to the active compensation demand of each station area with the type of the fault station area, adding the active compensation demand array of the fault station area into the demand array, and arranging the active compensation demand array of the fault station area in front of the demand array to update the demand array;

the converter margin updating unit is used for updating the converter margin of each transformer area in the system;

and the second power fixed value determining unit is used for determining a second power fixed value of the converter of each block according to the demand array, the margin array and the current converter margin of each block, and sending a control instruction to the corresponding converter according to the second power fixed value of the converter of each block so that the converter of each block outputs power according to the corresponding second power fixed value.

Preferably, the classifying unit classifies the station areas in the system, and includes:

Preferably, the first power fixed value determining unit, configured to perform dc-side load power distribution according to an order of remaining active margins of the cells in the non-faulty cell array, to determine a first power fixed value of a converter of a cell in the non-faulty cell array, includes:

Preferably, wherein the system further comprises: the active load array construction unit is used for:

Preferably, wherein the system further comprises: a third power fixed value determination unit configured to:

if the current net power of the converter at the jth station area is not satisfied, completely absorbing the power at the direct current side when the load redundancy is satisfied, determining a third power fixed value of the converter at the jth station area as the current net power at the direct current side, and updating the current net power at the direct current side to be 0;

Preferably, the load rate calculating unit updates the active load of each station zone in the system by using the following method, including:

P_load(i)＝P′_load(i)+P_set(i)，

the system calculates the load rate of each distribution area according to the updated active load by using the following modes:

wherein, lf (i) is the load factor of the ith station zone; p_load(i) The updated active load of the ith platform area; q_load(i) The reactive load of i transformer areas; s (i) is the iRated capacity of individual block; p'_load(i) The actual active load of the ith platform area; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained.

Preferably, the converter margin updating unit updates the converter margin of each station zone in the system, and includes:

P_per(i)＝P′_per(i)-P_set(i)，

P_per(i)＝P′_per(i)+P_set(i)，

Preferably, the determining unit of the margin and demand array calculates an active compensation margin of each normal station area and an active compensation demand of each heavy load station area according to the updated normal station area and heavy load station area, and includes:

wherein, P_dr(i) The active compensation allowance is the active compensation allowance when the ith station zone is a normal station zone; (i) rated capacity of the ith station area; lf lim (i) is the load rate limit value of the normal operation of the ith platform area; q_load(i) The reactive load of i transformer areas; p_load(i) The updated active load of the ith platform area; ep (i) is the active buffering interval for the ith station zone; p_dn(i) When the ith station area is a heavy load station areaActive compensation demand.

Preferably, the determining unit of the second power fixed value determines the second power fixed value of the converter of each block according to the demand array, the margin array and the current converter margin of each block, and includes:

Preferably, wherein the system further comprises:

the allowable capacity adjusting unit is used for acquiring the state of the converter in real time, and if the converter is in a shutdown state, the allowable capacity of the converter is adjusted to be 0; if the converter is in a constant direct-current voltage UdcQ operation mode, the allowable capacity of the converter is adjusted to be as follows: p'_per(i)＝P_per(i)-P_ep，i＝i_udcq(ii) a Wherein, P'_per(i) Is the adjusted allowable capacity; p_per(i) The capacity of the converter is the original allowable capacity; p_epThe current is a preset active buffering margin; i.e. i_udcqThe converters operating in UdcQ mode are numbered.

The invention provides an energy control method and system of a low-voltage transformer area flexible-direct interconnection energy-free system, aims to solve the problem of inter-transformer area load balance with complementary load space-time characteristics in the same area, and aims at the interconnection and mutual supply scenes of large-scale charging piles, direct-current data center access, seasonal load fluctuation and high-proportion distributed power supply access transformer areas.

Drawings

A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:

fig. 1 is a flow chart of an energy control method 100 for a low-voltage transformer area soft-direct interconnection non-energy storage system according to an embodiment of the invention;

fig. 2 is a schematic diagram of a flexible interconnection system of a low-voltage transformer area of a centralized power supply structure according to an embodiment of the invention;

fig. 3 is a flow chart of energy control of a non-energy-storage low-voltage distribution bay flexible-direct interconnection system according to an embodiment of the invention;

fig. 4 is a flow chart of determining a first power setting of a converter of a bay according to an embodiment of the invention;

fig. 5 is a flow chart of determining a third power rating of a converter of a bay according to an embodiment of the invention;

fig. 6 is a flow chart of determining a second power setting of a converter of a block according to an embodiment of the invention;

fig. 7 is a schematic structural diagram of an energy control system 700 of a low-voltage transformer area soft-straight interconnection non-energy storage system according to an embodiment of the invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

Fig. 1 is a flow chart of an energy control method 100 for a low-voltage transformer area soft-direct interconnection non-energy storage system according to an embodiment of the invention. As shown in fig. 1, an energy control method of a low-voltage transformer area flexible-direct interconnection non-energy storage system according to an embodiment of the present invention is directed to solving the problem of inter-transformer area load balancing with complementary load space-time characteristics in the same area, and aiming at a large-scale charging pile, a direct current data center access, seasonal load fluctuation, and an interconnection and mutual supply scenario of a high-proportion distributed power supply access transformer area, a transformer area convergence terminal may implement control functions such as power mutual aid, reactive voltage support, and the like, and a transformer area direct current side source network load coordination optimization function by configuring the method of the present invention. The energy control method 100 for the low-voltage transformer area flexible-direct interconnection non-energy storage system provided by the embodiment of the invention starts from step 101, and classifies transformer areas in the system in step 101.

Preferably, wherein said classifying the zones within the system comprises:

Preferably, wherein the system further comprises: acquiring the state of the current converter in real time, and if the current converter is in a shutdown state, adjusting the allowable capacity of the current converter to be 0; if the converter is in a constant direct-current voltage UdcQ operation mode, the allowable capacity of the converter is adjusted to be as follows: p'_per(i)＝P_per(i)-P_ep，i＝i_udcq(ii) a Wherein, P'_per(i) Is the adjusted allowable capacity; p_per(i) The capacity of the converter is the original allowable capacity; p_epThe current is a preset active buffering margin; i.e. i_udcqThe converters operating in UdcQ mode are numbered.

In the present invention, a low-voltage platform flexible interconnection system of a centralized power supply structure shown in fig. 2 is taken as an example. Fig. 2 contains typical low-voltage distribution area, AC load, bidirectional AC/DC converter, DC bus, and analog load on DC side, photovoltaic, etc. source load power unit; the system is fixed with a converter in a constant DC bus voltage IJdcQ mode.

In the present invention, the parameters are defined as follows:

1) setting N total transformer areas to be interconnected, taking the rectification direction as the positive power setting direction of the AC/DC, considering that a constant voltage mode converter needs to reserve a power regulation margin, and setting an active buffering margin Pep by a system; the rated capacity of each transformer area i is S (i), the capacity of a converter corresponding to each transformer area i is Pper (i), the load rate limit value of normal operation of each transformer area i is Iflim (i), the load rate limit value of each transformer area i under the condition that a system has a fault is faultlim (i), and generally, the load rate limit value is faultlim (i) and is greater than Iflim (i); the load rate acquired by each area i in real time is RTLF (i), and the power factor of each area i is PF (i); the active buffer interval of each station i is ep (i) for avoiding compensation oscillation.

2) And (4) counting the net power of each feeder line at the direct current side, wherein the summed net power at the direct current side is used for representing DCload, if DCload is greater than 0, the direct current load is represented, and if DCload is less than 0, the direct current load is represented as a direct current power source.

3) Considering the coordination control between the bidirectional AC/DC, three operation modes are defined as Status, and the corresponding state value is O in the PQ mode; the state value is 1 in the UdcQ mode; the state value is-1 in the V-f mode; the inverter operating in the PQ mode reads the power command value Pset at the present time.

4) And defining a platform area with no pressure at the 400V outlet side of the platform transformer, namely, the platform area of the converter running in a V-f mode is a fault platform area, otherwise, the platform area with the load rate lower than the load rate limit value is a normal platform area, and the platform area with the load rate more than or equal to the load rate limit value is a heavy load platform area.

5) The system needs to acquire the current converter state in real time, and if the converter operates off-grid, namely stops operating, the available capacity Pper of the converter is 0; allowable capacity P for converters operating in UdcQ mode_per(i) Comprises the following steps:

P_per(i)＝P_per(i)-P_ep，i＝i_udcq，

wherein, P'_per(i) Is the adjusted allowable capacity; p_per(i) The capacity of the converter is the original allowable capacity; p_epThe current is a preset active buffering margin; i.e. i_udcqNumbering converters operating in the UdcQ mode; only one converter in each set of flexible direct interconnection system can operate in a UdcQ mode, judgment needs to be made when the current operation state is scanned, and the allowable capacity of the converter is the difference value between the total capacity of the converter and the active buffering margin of the system.

6) Current output power P of converter operating in UdcQ mode_set(i) Comprises the following steps:

7) AC active load P of transformer area i_load(i) The calculation method of (1) is as follows;

P_load(i)＝RTLF×S(i)×PF-P_set(i)，

8) AC reactive load Q of transformer area i_load(i) The calculation method comprises the following steps:

referring to fig. 3, in the present invention, system basic information is input, system parameters in a current operation period are scanned, an active power setting value array Pset of a platform area interconnection port is defined and preset to 0, and then whether a fault platform area exists in the system is determined according to an operation mode of a converter obtained by scanning. If the converter in the transformer area operates in a V-f mode, determining the converter area as a fault transformer area; if the converter in the transformer area does not operate in the V-f mode and the load rate of the transformer area is smaller than the load rate limit value, determining that the transformer area is a normal transformer area; and if the converter in the transformer area does not operate in the V-f mode and the load rate of the transformer area is greater than or equal to the load rate limit value, determining the transformer area as a heavy-load transformer area.

In step 102, when no fault station zone exists in the system and the collected direct current side net power is positive, directly determining a non-fault station zone, calculating the residual active margin of each non-fault station zone, and sequencing according to the size of the residual active margin of each non-fault station zone to determine an active margin array of the non-fault station zone.

In step 103, according to the sequence of the remaining active margins of the blocks in the non-fault block active margin array, performing direct current side load power distribution to determine a first power fixed value of a converter of the block in the non-fault block array.

s14, if the current net power at the direct current side is 0 or S is more than N1, directly entering step 104; otherwise, the process proceeds to step S12.

Preferably, wherein the method further comprises:

Referring to fig. 3, in the present invention, when a fault station area does not exist in the system, it is first determined whether the collected dc side net power DCload is greater than 0, when the collected dc side net power DCload is positive, it indicates that the collected dc side net power DCload is a dc load, the non-fault station areas are directly counted, the remaining active margin Prdc of each non-fault station area is calculated, and the remaining active margins Prdc of each non-fault station area are sorted in a descending order according to the size of the remaining active margin of each non-fault station area to determine the non-fault station area array.

Wherein, the remaining active margin P of each station zone i_rdc(i) The calculation formula of (2) is as follows:

P_load(i) is the ith stationThe current active load of the zone; q_load(i) The current reactive load of the i transformer areas; and S (i) is the rated capacity of the ith station area.

Then, the remaining active margin P of the station region in the array is compared_dcdrAnd allowable capacity P of corresponding converter_perThe Prdc takes a smaller value, and executes load power distribution of the direct current side from large to small according to the active margin, and updates the P_set。

Specifically, the method for performing dc-side load power distribution according to the sequence of the remaining active margins of the cells in the non-faulty cell array according to the process shown in fig. 4 to determine the first power fixed value of the converter of the cell in the non-faulty cell array includes:

s11, initializing the number N1 of the transformer areas in the non-fault transformer area array with S equal to 1 and S equal to or less than; s is the sequence number of the transformer areas in the array of the non-fault transformer areas; for the same station area in different arrays, the sequence numbers may be different;

s12, selecting the residual active margin P of the S-th station area_rdc(s) and the minimum value of the allowable capacity of the corresponding converter is used as the residual active margin P of the ith station zone_rdc(s)；

S13, judging the residual active margin P of the S-th station area_rdc(s) whether or not the current DC side net power DCload is satisfied.

If the power value P does not meet the requirement of the direct-current side load, power is provided according to the requirement of the direct-current side load, and a first power fixed value P of the converter of the s-th non-fault area is determined_set(s) is the current net power on the direct current side, and the current net power on the direct current side DCload is updated to be 0;

if yes, determining that the allowance is insufficient, providing according to the maximum allowance, and determining a first power fixed value P of the converter of the s-th non-fault station area_set(s) is the remaining active margin P of the s-th station zone_rdc(s), updating the net power of the direct current side to be the difference value between the current net power of the direct current side and the active load of the s-th station area, namely DCload-P_rdc(s), update s ═ s + 1;

s14, if the current net DC power DCload at the DC side is 0 or S > N1, directly entering step 104; otherwise, the process proceeds to step S12.

Referring to fig. 3, in the present invention, when a fault station exists in the system, the load rate limit of all the station areas is first increased from Iflim to the load rate limit faulltlim under the fault condition, and the fault station areas are arranged in ascending order according to the size of the active load of the station area before the fault, so as to determine the active load array of the fault station area.

And then, judging whether the collected net power DCload on the direct current side is greater than 0, when the collected net power DCload on the direct current side is negative, indicating that the collected net power DCload is a direct current power source, counting the non-fault transformer areas, and performing ascending arrangement on the actual active load Pload of each non-fault transformer area to determine a non-fault transformer area array.

Then, the active load arrays of the transformer areas are reconstructed, and the active loads of the non-fault transformer areas are sorted from small to small according to the load of the fault transformer area array from small to large.

Then, comparing the active load P of the region in the active load array of the region_loadAnd allowable capacity P of corresponding converter_perTaking a smaller value, executing DC side power source distribution according to the active load from large to small, and updating P_set。

Specifically, according to the process shown in fig. 5, the method for determining the third power fixed value of the converter of the station area in the active load array performs the dc-side load power distribution according to the order of the active loads of the station area in the active load array, including:

s21, initializing the number N2 of the transformer areas in the active load array, wherein j is equal to 1 and j is equal to or less than the number N2; j is the sequence number of the transformer area in the active load array of the transformer area; for the same station area in different arrays, the sequence numbers may be different;

s22, selecting the active load P of the jth platform area_load(j) And the minimum value of the allowable capacity of the corresponding converter is taken as the active load P of the jth station area_load(j)；

S23, judging the active load P of the jth station area_load(j) Whether the absolute value of the current direct current side net power, namely | DCload |, is satisfied or not.

If the current net power of the converter of the jth station area is not satisfied, completely absorbing the power of the direct current side when the load redundancy is satisfied, determining that a third power fixed value of the converter of the jth station area is the current net power of the direct current side, and updating the current net power of the direct current side to be 0;

if so, determining that the load is insufficient, and determining a third power fixed value P of the current converter of the jth station area according to the DC side power consumed by the maximum load_set(j) Is the active load P of the jth station area_load(j) Updating the absolute value | DCload | of the dc side net power to be the difference between the absolute value of the current dc side net power and the active load of the jth station zone, that is, | DCload | ═ DCload | -P_load(j) And updating j ═ j + 1;

s24, if the current net power of the direct current side is 0 or j is more than N2, directly entering step 104; otherwise, the process proceeds to step S22. In step 104, the active load of each block in the system is updated, the load rate of each block is calculated according to the updated active load, and the normal block and the heavy load block are determined again according to the updated load rate of the block.

P_load(i)＝P′_load(i)+P_set(i)，

wherein, lf (i) is the load factor of the ith station zone; px_oad(i) The updated active load of the ith platform area; q_load(i) The reactive load of i transformer areas; (i) rated capacity of the ith station area; p'_load(i) The actual active load of the ith platform area; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained.

Referring to fig. 3, in the present invention, after determining the power fixed value of the converter at the station side, the active load of each station in the system is updated in the following manner, including:

P_load(i)＝P′_load(i)+P_set(i)，

wherein, lf (i) is the load factor of the ith station zone; p_load(i) The updated active load of the ith platform area; q_load(i) The reactive load of i transformer areas; (i) rated capacity of the ith station area; p'_load(i) The actual active load of the ith platform area; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained.

And then, re-determining the normal distribution area and the heavy-load distribution area according to the updated load rate of the distribution area. The principle of determination is still: if the load rate of the distribution area is smaller than the load rate limit value, determining the distribution area as a normal distribution area; and if the load rate of the transformer area is greater than or equal to the load rate limit value, determining the transformer area as a heavy load transformer area.

In step 105, calculating an active compensation allowance of each normal station area and an active compensation demand of each heavy load station area according to the updated normal station area and the updated heavy load station area, sequencing according to the size of the active compensation allowance of each normal station area to determine an allowance array, and sequencing according to the size of the active compensation demand of each heavy load station area to determine a demand array.

wherein, P_dr(i) The active compensation allowance is the active compensation allowance when the ith station zone is a normal station zone; (i) rated capacity of the ith station area; lf lim (i) is the load rate limit value of the normal operation of the ith platform area; q_load(i) The reactive load of i transformer areas; p_load(i) The updated active load of the ith platform area; ep (i) is the active buffering interval of the ith station area to avoid causing oscillation; p_dn(i) And the required active power compensation quantity is the required active power compensation quantity when the ith station area is the heavy station area.

Referring to fig. 3, in the present invention, after the heavy load station area and the normal station area are re-determined according to the updated load rate, the active compensation allowance of each normal station area and the active compensation demand of each heavy load station area are calculated according to the updated normal station area and the updated heavy load station area, and the active compensation allowance of each normal station area and the active compensation demand of each heavy load station area are sorted to determine a margin array Pr, and the active compensation demand of each heavy load station area is sorted to determine a demand array Pn.

In step 106, determining that the active compensation demand of the fault station zone is equal to the active load, determining an active compensation demand array of the fault station zone according to the active compensation demand of each station zone with the type of the fault station zone, adding the active compensation demand array of the fault station zone into the demand array, and arranging the active compensation demand array of the fault station zone in the front to update the demand array.

In the invention, the active compensation demand of a fault area is equal to the active load, after the active power load is updated, a new fault area array, namely a fault area active compensation demand array Pf is determined according to the size of the active compensation demand of each area with the type of the fault area, and the fault area active compensation demand array Pf is added into the demand array Pn to update the demand array, namely the updated Pn is [ Pf, Pn ].

At step 107, the converter margin for each bay within the system is updated.

P_per(i)＝P′_per(i)-P_set(i)，

P_per(i)＝P′_per(i)+P_set(i)，

wherein, P_per(i) And P'_per(i) Margins of the current converter of the ith transformer area after updating and before updating are respectively reserved; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained. In step 108, a second power fixed value of the converter of each block is determined according to the demand array, the margin array and the current converter margin of each block, and a control command is sent to the corresponding converter according to the second power fixed value of the converter of each block, so that the converter of each block outputs power according to the corresponding second power fixed value. Preferably, the determining a second power fixed value of the converter of each block according to the demand array, the margin array and the current converter margin of each block comprises:

In the invention, the heavy load district array is updated, and the active compensation demand of the heavy load district is sequenced from large to small according to the active load of the fault district from large to small. Then, comparing the active margin of the transformer area with the margin of the current converter, taking the smaller value, comparing the heavy-load transformer area array with the margin of the current converter, and taking the smaller value; when the active margin of the transformer area is insufficient, performing active compensation according to the maximum margin; if the full power can meet the power requirement of the fault area or the heavy load area, compensating according to the requirement, and determining a second power fixed value; and after calculation, outputting a remote adjusting instruction to the fusion terminal or the corresponding current converter according to the second power fixed value.

Specifically, in the present invention, a flow of determining a second power fixed value of the converter of each block according to the demand array, the margin array, and the current converter margin of each block is shown in fig. 6, and includes:

s31, initializing h to 1, t to 1, h is less than or equal to the number N3 of the station areas in the demand array Pn, and t is less than or equal to the number N4 of the station areas in the margin array Pr;

s32, selecting the active compensation demand P of the h-th distribution room_dn(h) And taking the minimum value of the allowable capacity of the corresponding converter as the active compensation demand P of the h-th station area_dn(h)；

S33, selecting an active compensation allowance P of the tth station area_dr(t) and the minimum value of the allowable capacity of the corresponding converter is used as the active compensation allowance P of the t-th station zone_dr(t)；

S34, judging the active compensation allowance P of the t-th station area_dr(t) whether or not the active compensation demand P of the h-th station area is satisfied_dn(h) (ii) a Wherein,

if the current power requirement is not met, power is transferred according to the requirement of the heavy load transformer area, a second power fixed value Pset of the current converter of the h-th transformer area is determined to be the difference value between the current power fixed value Pset and the active compensation demand of the h-th transformer area, the second power fixed value Pset of the current converter of the t-th transformer area is determined to be the sum of the current power fixed value Pset and the active compensation demand of the current converter of the h-th transformer area, the power fixed value is updated to be the current second power fixed value of the corresponding transformer area, h +1 is updated, and the step S35 is carried out;

if the current power setting value is met, determining that the margin is insufficient, determining that a second power setting value Pset of the current converter of the h-th station zone is a difference value between the current power setting value Pset and an active compensation margin of the t-th station zone according to the maximum margin exclusive supply, determining that the second power setting value Pset of the current converter of the t-th station zone is a sum of the current power setting value Pset and the active compensation margin of the t-th station zone, updating the active compensation demand of the h-th station zone to be a difference value between the current active compensation demand of the h-th station zone and the active compensation margin of the t-th station zone, updating the power setting value to be the current second power setting value of the corresponding station zone, and directly entering step S36;

The initial parameter settings are shown in table 1 according to different initial states of the flexible interconnection system of the platform area.

TABLE 1 initial parameters Table

Number of cells N	3
		Rated capacity S of district_i	400kVA
Active buffer capacity P of system_ep	60kW
		Normal load rate limit lflim	0.5
Fault load rate limit faultlim	0.7
		Inverter operation mode Status	A first transformer area and a second transformer area: a PQ mode; a third station area: u shape_dcQ mode
Power factor PF	1
		DC side net power DCload	60kW (load)/-60 kW (power source)

The power mutual aid and fault transfer effects obtained by the energy control method of the present invention are shown in table 2. Wherein,

the working condition I is as follows: in the initial state of the system, all three transformer areas are in a light load state, the load rates are (0.3,0.2 and 0.4) respectively, the initial direct current load is 60kW, the converter in the UdcQ mode provides direct current power shortage, the voltage stability of a direct current bus is guaranteed, after the energy management and control strategy is executed, the load rate of the current transformer area II is scanned to be the lowest, and under the condition that the buffer interval of the transformer areas is 10kW, 110kW active margin can be provided, so that the direct current load at the moment is provided by the transformer area II, the active power instruction output to the three converters by the strategy is (0,60 and 0), the corresponding load rates are (0.3,0.35 and 0.25), and the three transformer areas are still in the light load state.

Working conditions are as follows: the load rate of a station zone II in the initial state of the system is 0.8, the system belongs to heavy load, the initial direct current load is 60kW, a converter in an UdcQ mode provides direct current power shortage, after an energy management and control strategy is executed, the load rate of a current station zone III is scanned to be the lowest to meet the requirement of the direct current load, the station zone II is heavily loaded, a station zone buffer interval of 10kW is considered, and the active compensation requirement of 130kW is provided, at the moment, the converter in the UdcQ mode needs to consider that the active buffer capacity of the system is 60kW, namely, the converter can only provide 140kW at most, and provides 80kW power margin while meeting 60kW direct current load, while the station zone I only has 30kW power margin under the condition that the station zone I is not heavily loaded, and the strategy output instruction is (30, -110,140), and the corresponding load rate is changed into (0.475,0.525, 0.4).

Working conditions are as follows: when the system is in an initial state, the station area is in a triple load state, a stable load of 60kW is provided by the station area I on the direct current side, the scanning is performed on the current station area II, the load is lightest, and the direct current load is borne, so that the actual load rate of the station area I is 0.15, an active margin of 130kW can be provided, the station area triple load has a power demand of 90kW, the station area I supplies power to the station area III, the strategy output instruction is (90,60, -90), and the corresponding load rate is changed into (0.375,0.25, 0.475).

Working conditions are as follows: in the initial state of the system, the load rate of the second zone is the lowest, but the corresponding converter is in a shutdown state, so that the direct current load and the active demand of the third 50kW zone are both provided by the first zone, the strategy output instruction is (110,0, -50), and the corresponding load rate is changed into (0.425,0.1, 0.475).

Working condition five: the rated capacity of a converter in the second transformer area is changed to 60kW, the active buffering interval of each transformer area is changed to 0, namely the upper limit of the active margin provided by the second transformer area is 60kW, the load rate of the second transformer area in the initial state of the system is lowest, and the direct current load can be borne but the upper limit of the capacity of the second transformer area is reached; the operating condition of the zone one heavy load is relieved by the zone three, the strategy output command is (-80,60,80), and the corresponding load rate becomes (0.5,0.25, 0.35).

Working condition six: in the initial state of the system, the first transformer area is in fault, the corresponding converter is in a V-f operation mode, the third transformer area is in an UdcQ mode, the first transformer area bears the load of the first transformer area and bears the direct current load, the system scans that the actual load rate of the current non-fault transformer area (second and third) is the lowest (0.15), the third transformer area bears the direct current side load, at the moment, the load rate of the third transformer area is improved to 0.3, the fault power of the first transformer area is provided by the second transformer area, the strategy output instruction is (-120, 0), and the corresponding load rate is changed to (0,0.5, 0.3).

A seventh working condition: changing the load at the direct current side into a power source, namely, transmitting power to the transformer area side, wherein the transformer area II is overloaded in the initial state of the system, the transformer area II bears the output power of the power source at the direct current side, the load rate of the transformer area II is reduced to 0.45 at the moment, namely, the transformer area II is in a normal state, the power supply does not need to be converted, and the strategy output instruction is (0, -60, 0); the corresponding load factor becomes (0.4,0.45, 0.25).

TABLE 2 Power mutual aid and failure transfer effect table

The method considers direct-current side source and charge bidirectional power coordination optimization aiming at the low-voltage platform area flexible interconnection energy-free system which is arranged in a centralized manner, can adapt to the access of direct-current source charges such as photovoltaic power, charging piles and the like, can improve the power supply level and the interaction capacity of a multi-element fusion platform area, and is one of important ways for realizing regional autonomy. When the system normally operates, the system can realize power flow regulation, load balancing and platform area dynamic capacity increase; when a single transformer area has a fault, the subordinate important loads can be supplied by other transformer areas or energy storage devices, so that the power supply reliability is improved.

Fig. 7 is a schematic structural diagram of an energy control system 700 of a low-voltage transformer area soft-straight interconnection non-energy storage system according to an embodiment of the invention. As shown in fig. 7, an embodiment of the invention provides an energy control system 700 for a low-voltage transformer area soft and straight interconnection non-energy storage system, including: the system comprises a station zone classification unit 701, a non-fault station zone array determination unit 702, a first power fixed value determination unit 703, a load rate calculation unit 704, a margin and demand array determination unit 705, a demand array update unit 706, a converter margin update unit 707 and a second power fixed value determination unit 708.

Preferably, the station area classifying unit 701 is configured to classify station areas in the system.

Preferably, the classifying unit 701 classifies the station areas in the system, including:

Preferably, wherein the system further comprises:

the allowable capacity adjusting unit is used for acquiring the state of the converter in real time, and if the converter is in a shutdown state, the allowable capacity of the converter is adjusted to be 0; if the converter is in a constant direct-current voltage UdcQ operation mode, the allowable capacity of the converter is adjusted to be as follows: p'_per(i)＝P_per(i)-P_ep，i＝i_udcq(ii) a Wherein, P'_per(i) Is the adjusted allowable capacity; p_per(i) For the original permission of the current converterThe allowable capacity; p_epThe current is a preset active buffering margin; i.e. i_udcqThe converters in the UdcQ mode of operation are numbered.

Preferably, the non-faulty station zone array determining unit 702 is configured to, when a faulty station zone does not exist in the system and the collected dc-side net power is positive, directly determine a non-faulty station zone, calculate a remaining active margin of each non-faulty station zone, and sort according to a size of the remaining active margin of each non-faulty station zone to determine a non-faulty station zone active margin array.

Preferably, the first power fixed value determining unit 703 is configured to perform, according to the sequence of the remaining active margins of the blocks in the non-faulty block active margin array, dc-side load power distribution to determine a first power fixed value of the converter of the block in the non-faulty block array.

Preferably, the first power fixed value determining unit 703, according to the order of the remaining active margins of the blocks in the non-faulty block array, performs the dc-side load power distribution to determine the first power fixed value of the converter of the block in the non-faulty block array, includes:

Preferably, the load rate calculating unit 704 is configured to update an active load of each station area in the system, calculate a load rate of each station area according to the updated active load, and re-determine a normal station area and a heavy load station area according to the updated load rate of the station area.

Preferably, the load rate calculating unit 704 updates the active load of each station zone in the system by using the following method, including:

P_load(i)＝P′_load(i)+P_set(i)，

Preferably, the margin and demand array determining unit 705 is configured to calculate an active compensation margin of each normal station area and an active compensation demand of each heavy load station area according to the updated normal station area and the updated heavy load station area, sort according to the size of the active compensation margin of each normal station area to determine a margin array, and sort according to the size of the active compensation demand of each heavy load station area to determine the demand array.

Preferably, the determining unit 705 of the margin and demand array calculates an active compensation margin of each normal station area and an active compensation demand of each heavy load station area according to the updated normal station area and heavy load station area, and includes:

Preferably, the demand array updating unit 706 is configured to determine that the active compensation demand of the fault station zone is equal to the active load, determine the active compensation demand array of the fault station zone according to the size of the active compensation demand of each station zone of which the type is the fault station zone, add the active compensation demand array of the fault station zone to the demand array, and arrange the active compensation demand array of the fault station zone before the active compensation demand array so as to update the demand array.

Preferably, the converter margin updating unit 707 is configured to update the converter margin of each station zone in the system.

Preferably, the converter margin updating unit 707 updates the converter margin of each station zone in the system, including:

P_per(i)＝P′_per(i)-P_set(i)，

P_per(i)＝P′_per(i)+P_set(i)，

Preferably, the second power fixed value determining unit 708 is configured to determine a second power fixed value of the converter of each block according to the demand array, the margin array and the current converter margin of each block, and send a control instruction to the corresponding converter according to the second power fixed value of the converter of each block, so that the converter of each block outputs power according to the corresponding second power fixed value.

The energy control system 700 of the low-voltage transformer area flexible-straight interconnected energy-free system according to the embodiment of the present invention corresponds to the energy control method 100 of the low-voltage transformer area flexible-straight interconnected energy-free system according to another embodiment of the present invention, and is not described herein again.

The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims

1. An energy control method of a low-voltage transformer area flexible-straight interconnection energy-free system is characterized by comprising the following steps:

step 1, classifying the distribution areas in the system;

step 3, performing direct-current side load power distribution according to the sequence of the residual active margin of the transformer areas in the non-fault transformer area array to determine a first power fixed value of a current converter of the transformer areas in the non-fault transformer area array;

2. The method of claim 1, wherein the classifying the zones within the system comprises:

3. The method of claim 1, wherein the performing DC-side load power distribution according to the order of the remaining active margin of the zones in the array of non-faulty zones to determine a first power rating of a converter of a zone in the array of non-faulty zones comprises:

4. The method of claim 1, further comprising:

5. The method of claim 4, further comprising:

6. The method according to claim 1 or 5, wherein the method updates the active load of each zone in the system by using the following method, comprising:

P_load(i)＝P'_load(i)+P_set(i),

7. The method of claim 1, wherein updating the converter margin for each bay within the system comprises:

P_per(i)＝P'_per(i)-P_set(i)，

P_per(i)＝P'_per(i)+P_set(i)，

8. The method of claim 1, wherein the calculating the active compensation margin of each normal distribution area and the active compensation demand of each heavy-load distribution area according to the updated normal distribution area and heavy-load distribution area comprises:

wherein, P_dr(i) The active compensation allowance is the active compensation allowance when the ith station zone is a normal station zone; (i) rated capacity of the ith station area; lflim (i) is the load rate limit value of the normal operation of the ith station area; q_load(i) The reactive load of i transformer areas; p_load(i) The updated active load of the ith platform area; ep (i) is the active buffering interval for the ith station zone; p_dn(i) And the required active power compensation quantity is the required active power compensation quantity when the ith station area is the heavy station area.

9. The method of claim 1, wherein determining a second power setting for the converter of each bay from the demand array, the margin array, and a current converter margin for each bay comprises:

10. The method of claim 1, further comprising:

11. An energy control system of a low-voltage transformer area flexible-straight interconnection energy-storage-free system, characterized in that the system comprises:

the margin and demand array determining unit is used for calculating the active compensation margin of each normal station area and the active compensation demand of each heavy load station area according to the updated normal station area and the updated heavy load station area, sequencing the margin and demand array according to the size of the active compensation margin of each normal station area to determine a margin array, and sequencing the margin and demand array according to the size of the updated active load of the fault station area and the active compensation demand of each heavy load station area to determine a demand array;

12. The system of claim 11, wherein the classification unit classifies the station areas within the system, comprising:

if the converter of the transformer area is operated in a non-V-f mode and the load rate of the transformer area is smaller than the load rate limit value, determining that the transformer area is a normal transformer area;

and if the converter of the transformer area operates in a non-V-f mode and the load rate of the transformer area is greater than or equal to the load rate limit value, determining the transformer area as a heavy load transformer area.

13. The system according to claim 11, wherein the first power fixed value determining unit performs dc-side load power distribution according to an order of remaining active margins of the zones in the non-faulty zone array to determine a first power fixed value of a converter of a zone in the non-faulty zone array, including:

14. The system of claim 11, further comprising: the active load array construction unit is used for:

15. The system of claim 14, further comprising: a third power fixed value determination unit configured to:

16. The system according to claim 11 or 15, wherein the load factor calculating unit updates the active load of each station zone in the system by using the following method, comprising:

P_load(i)＝P'_load(i)+P_set(i),

wherein, lf (i) is the load factor of the current converter of the ith station area; p_load(i) The updated active load of the ith platform area; q_load(i) The reactive load of i transformer areas; (i) rated capacity of the ith station area; p'_load(i) The actual active load of the ith platform area; p_set(i) The first power fixed value or the third power fixed value of the current converter of the ith station zone is obtained.

17. The system of claim 11, wherein the converter margin updating unit updates the converter margin of each bay in the system, and comprises:

P_per(i)＝P'_per(i)-P_set(i)，

P_per(i)＝P'_per(i)+P_set(i)，

18. The system of claim 11, wherein the margin and demand array determining unit calculates an active compensation margin of each normal distribution area and an active compensation demand of each heavy loading distribution area according to the updated normal distribution area and heavy loading distribution area, and comprises:

19. The system according to claim 10, wherein the second power fixed value determining unit determines a second power fixed value of the converter of each bay according to the demand array, the margin array and the current converter margin of each bay, and comprises:

20. The system of claim 11, further comprising:

the allowable capacity adjusting unit is used for acquiring the state of the converter in real time, and adjusting the allowable capacity of the converter to be 0 if the converter is in a shutdown state; if the converter is in a constant direct-current voltage UdcQ operation mode, the allowable capacity of the converter is adjusted to be as follows: p'_per(i)＝P_per(i)-P_ep，i＝i_udcq(ii) a Wherein, P'_per(i) Is the adjusted allowable capacity; p_per(i) The capacity of the converter is the original allowable capacity; p_epThe current is a preset active buffering margin; i.e. i_udcqThe converters operating in UdcQ mode are numbered.