阅读说明：本技术 一种中低压直流输电系统的计量方法及系统 (Metering method and system for medium and low voltage direct current transmission system ) 是由 刘炜 陆春光 王朝亮 章江铭 李亦龙 蒋群 黄荣国 宋磊 孙钢 于淼 张哲玮 于 2021-01-20 设计创作，主要内容包括：本发明公开了一种中低压直流输电系统的计量方法及系统,属于中低压直流输电设备技术领域。本发明的一种中低压直流输电系统的计量方法,包括以下步骤：第一步,采集系统运行信息,并对电能进行计量；第二步,读取采集到的计量数据以及设备报警信息,并对数据进行存储；第三步,把采集得到的数据进行处理,分析系统的运行状态以及计算电费；第四步,对系统运行状态进行仿真。本发明经过不断探索以及试验,通过采集系统实际运行信息,对电能进行计量；同时能够根据采集信息,对电能进行有效管理和计量结果校对,方案科学、合理、准确；能够满足电网公司以及用户对中低压直流输电系统科学计量的要求。(The invention discloses a metering method and a metering system of a medium and low voltage direct current transmission system, and belongs to the technical field of medium and low voltage direct current transmission equipment. The invention discloses a metering method of a medium and low voltage direct current transmission system, which comprises the following steps: firstly, collecting system operation information and metering electric energy; secondly, reading the collected metering data and equipment alarm information, and storing the data; thirdly, processing the acquired data, analyzing the running state of the system and calculating the electric charge; and fourthly, simulating the running state of the system. Through continuous exploration and test, the electric energy is measured by acquiring the actual operation information of the system; meanwhile, the electric energy can be effectively managed and the metering result can be corrected according to the collected information, and the scheme is scientific, reasonable and accurate; the method can meet the requirements of scientific measurement of medium and low voltage direct current transmission systems of power grid companies and users.)

1. A metering method of a medium and low voltage direct current transmission system is characterized by comprising the following steps:

firstly, collecting system operation information and metering electric energy;

secondly, reading the collected metering data and equipment alarm information, and storing the data;

thirdly, processing the acquired data, analyzing the running state of the system and calculating the electric charge;

data processing includes, but is not limited to: flicker analysis, ripple analysis, tip, peak, valley and level analysis and system direct current power flow analysis; issuing a system operation instruction according to the data processing result, and transmitting the instruction to the control station through the server, thereby realizing electric energy management;

fourthly, simulating the running state of the system, and giving a reference range of the metering result of the key metering point as a calibration standard of the metering result; if the simulation result is larger than the reference range and no alarm information exists at the moment, sending information to a person in charge of the metering point where the simulation result is located, and informing the person to go to the position where the metering point is located to troubleshoot faults.

2. A method of metering a medium and low voltage DC transmission system according to claim 1,

in the first step, the measurement of the electric energy comprises the calculation of direct current power, which comprises an effective value method, an average value method or an instantaneous value method; wherein, the sampling time is T, and the sampling start time is T₀The voltage sampling instantaneous value is u (t), the current sampling instantaneous value is i (t), and the expressions of the three calculation schemes are respectively:

3. a method of metering a medium and low voltage DC transmission system according to claim 1,

in the second step, data reading adopts an open form, and supports expansion and new equipment addition;

the data storage is written by java language, and the https protocol and the JSON or XML form are used for data transmission.

4. A method of metering a medium and low voltage DC transmission system according to claim 1,

in the third step, a modeling fitting method is adopted to carry out flicker analysis and ripple analysis;

the voltage expression of the voltage signal in T time is as follows:

the target is fit to estimate the parameters during T timeAnd (3) if the absolute value of the difference between the estimation expression (4) and the sampling voltage is as small as possible, fitting the target expression as follows:

wherein u (t) is a voltage instantaneous value obtained by collection; Δ u is the voltage flicker amplitude during time T; u shape_mIs the ripple amplitude; omega is ripple frequency;is the ripple phase.

5. A method of metering a medium to low voltage DC transmission system according to claim 4,

the fitting target expression is searched by adopting a simulated annealing algorithm under the condition of a given estimation parameter searching range;

the searching steps are as follows:

step 1: number of initialization iterations k, temperature parameter C_pAccuracy epsilon, cooling coefficient alpha, randomly generating a set of estimation parameters p_i；

Step 2: initial feasible solution ═ whenFront solution p_iCalculating a fitting objective function value J (p)_i)；

And step 3: judgment of equilibrium Condition J (p)_i) If the epsilon is less than epsilon, turning to a step 6 if the epsilon is true, or turning to a step 4-5 if the epsilon is not true;

and 4, step 4: randomly generating a set of estimated parameters p in the neighborhood of the current solution_jCalculating its fitting objective function value J (p)_j)；

And 5: performing an acceptance criterion, if J (p)_j)≤J(p_i) Then receive p_jReturning to the step 2 for feasible solution; otherwise, judging the acceptance probabilityIf true, accept p_jIf the solution is feasible, returning to the step 2, otherwise, directly returning to the step 2;

step 6: if the iteration times are reached, stopping the iteration; reduction of temperature, C'_p＝αC_pGo back to step 2.

6. A method of metering a medium and low voltage DC transmission system according to claim 1,

in the fourth step, the simulation process specifically includes the following steps:

s1, logging in the system by a terminal manager;

s2, after logging in, the terminal manager inputs weather forecast conditions, load forecast conditions, direct current converter station control modes, system direct current bus voltage standard values and system direct current bus power standard values into the system;

s3, after data entry, running simulation to obtain a simulation result;

s4, comparing the simulation result with the reference range of the metering point;

if the simulation result is greatly different from the reference range of the metering point and no alarm information exists at the moment, the electric energy management layer sends information to a person in charge of the metering point through the server and informs the person to go to the position of the metering point to troubleshoot faults.

7. A metering system of a medium and low voltage dc transmission system, characterized in that a metering method of a medium and low voltage dc transmission system according to any one of claims 1 to 6 is applied, which comprises: the system comprises an acquisition layer, a data management layer and an electric energy management layer; the electric energy management, the calibration of the metering result and the safety alarm are realized;

the acquisition layer is used for acquiring system operation information and detecting the system operation condition and comprises an electric energy acquisition module and a communication module;

the electric energy acquisition module is used for acquiring electric energy information and establishing connection between a physical entity and a network through the communication module;

the electric energy acquisition module triggers an alarm when measuring out-of-limit voltage and current information;

the data management layer is used for completing the transmission, storage and type processing of data and is divided into two modules, namely a network service module and a storage module;

the network service module is used for reading the metering data transmitted by the acquisition layer and reading the alarm information of the electric energy acquisition module;

the storage module is used for storing the data read by the network service module;

the electric energy management layer is used for reading an instruction given by an operator, reading electric energy measured by the electric energy acquisition module, and further analyzing the running state and the charging condition of the direct current distribution network system;

the electric energy management layer is integrated with a simulation system and used for simulating a metering result by reading an instruction given by an operator.

8. A metering system for a medium and low voltage DC power transmission system according to claim 7,

the electric energy acquisition module comprises a voltage divider, a current divider, a merging module and an electric energy metering module;

the electric energy metering module conforms to national standard GB/T33708-2017 and industrial standards DL/T1484-2015 and DL/T448-2016;

the voltage divider converts the direct-current voltage to be measured into voltage of 100V and the precision is 0.2 level;

the current divider converts the direct current to be measured into 20A current with the precision of 0.2 level;

setting a voltage and current out-of-limit alarm;

the communication module comprises an ESP8266 module and uploads the alarm event to the cloud end through a Wi-Fi network.

9. A metering system for a medium and low voltage DC power transmission system according to claim 8,

the acquisition layer is connected with the data management layer through a communication module;

the communication module comprises but is not limited to infrared radio frequency, Bluetooth and ZigBee based communication;

the equipment in one data management layer corresponds to the equipment in one or more acquisition layers;

the network service module is provided with a network server and is used for reading the metering data and the alarm information transmitted by the acquisition layer equipment;

the storage module is provided with a database which adopts an open form and supports expansion and new equipment addition;

the network service module and the storage module are both written by java language, and data transmission is carried out by using https protocol and JSON or XML form.

10. The metering method and system for medium and low voltage DC transmission system according to claim 9,

the electric energy management layer comprises a server, a computer and a data processing module;

each device in each power management layer corresponds to a plurality of devices in the data management layer;

the server reads data from the data management layer or the acquisition layer through a TCP/IP protocol;

the acquired data is transmitted to a data processing module to perform charging calculation and running state analysis on the metering system;

data processing modules include, but are not limited to: flicker analysis, ripple analysis, tip, peak, valley and level analysis and system direct current power flow analysis;

and a terminal operator issues a system operation instruction through an analysis result, and the instruction is transmitted to the control station through the server, so that the electric energy management is realized.

Technical Field

The invention relates to a metering method and a metering system of a medium and low voltage direct current transmission system, and belongs to the technical field of medium and low voltage direct current transmission equipment.

Background

In recent years, dc transmission technology has been rapidly developed, but research on metering of electric energy in medium-voltage dc transmission systems has been temporarily less. At present, the related national standards and industry standards have more detailed specifications on direct current measurement below 1000V, but related researches are still in a starting stage for measuring medium-voltage direct current, such as a 10kV bus direct current distribution system.

The invention discloses a Chinese patent (publication number CN104655990A) which discloses a medium-low voltage distribution network simulation system based on energy feedback, comprising an input incoming cabinet, wherein the input incoming cabinet is connected with a boosting transformer lead, the boosting transformer is connected with a high-voltage meter lead, the high-voltage meter is connected with a first cable simulation device lead, the first cable simulation device is connected with a step-down transformer lead, the step-down transformer is connected with a second cable simulation device lead, the second cable simulation device is connected with a low-voltage outgoing cabinet lead, the low-voltage outgoing cabinet is connected with an electronic load lead, and the electronic load is connected with an isolation transformer lead; the problems that no special energy-saving loss-reducing energy efficiency real-time monitoring system exists in the prior art, in an electrical equipment test, the load is usually carried out in an RLC impedance load box energy consumption discharging mode, the test precision is low, the electric energy is seriously wasted, the load is difficult to meet the continuous adjusting capability of different working conditions, devices are easy to age and burn out due to small power, the thermal stability is poor, the load form is single and the like are solved.

According to the scheme, the line impedance of the medium-low voltage distribution network under different line lengths and the voltage fluctuation condition of the medium-low voltage distribution network can be simulated, and the influences of different load conditions, harmonic wave environments, three-phase unbalance degrees and the like on the energy efficiency of primary equipment of the distribution network are analyzed.

However, the scheme is a pure medium and low voltage distribution network simulation system, and cannot perform electric energy management and measurement result correction on an actual medium and low voltage direct current transmission system, and cannot meet the requirements of a power grid company and users on scientific measurement of the medium and low voltage direct current transmission system.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a device which can collect the actual operation information of a system and measure electric energy; meanwhile, the scheme of effectively managing electric energy and checking the metering result according to the acquired information is scientific, reasonable and accurate, and the metering method and the metering system of the medium and low voltage direct current power transmission system can meet the scientific metering requirements of a power grid company and a user on the medium and low voltage direct current power transmission system.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a metering method of a medium and low voltage direct current transmission system comprises the following steps:

firstly, collecting system operation information and metering electric energy;

secondly, reading the collected metering data and equipment alarm information, and storing the data;

thirdly, processing the acquired data, analyzing the running state of the system and calculating the electric charge;

data processing includes, but is not limited to: flicker analysis, ripple analysis, tip, peak, valley and level analysis and system direct current power flow analysis; issuing a system operation instruction according to the data processing result, and transmitting the instruction to the control station through the server, thereby realizing electric energy management;

fourthly, simulating the running state of the system, and giving a reference range of the metering result of the key metering point as a calibration standard of the metering result; if the simulation result is larger than the reference range and no alarm information exists at the moment, sending information to a person in charge of the metering point where the simulation result is located, and informing the person to go to the position where the metering point is located to troubleshoot faults.

Through continuous exploration and test, the electric energy is measured by acquiring the actual operation information of the system; meanwhile, the electric energy can be effectively managed and the metering result can be corrected according to the collected information, and the scheme is scientific, reasonable and accurate; the method can meet the requirements of scientific measurement of medium and low voltage direct current transmission systems of power grid companies and users.

As a preferable technical measure:

in the first step, the measurement of the electric energy comprises the calculation of direct current power, which comprises an effective value method, an average value method or an instantaneous value method; wherein, the sampling time is T, and the sampling start time is T₀The voltage sampling instantaneous value is u (t), the current sampling instantaneous value is i (t), and the expressions of the three calculation schemes are respectively:

as a preferable technical measure:

in the second step, data reading adopts an open form, and supports expansion and new equipment addition;

the data storage is written by java language, and the https protocol and the JSON or XML form are used for data transmission.

As a preferable technical measure:

in the third step, a modeling fitting method is adopted to carry out flicker analysis and ripple analysis;

the voltage expression of the voltage signal in T time is as follows:

the target is fit to estimate the parameters during T timeAnd (3) if the absolute value of the difference between the estimation expression (4) and the sampling voltage is as small as possible, fitting the target expression as follows:

wherein u (t) is a voltage instantaneous value obtained by collection; Δ u is the voltage flicker amplitude during time T; u shape_mIs the ripple amplitude; omega is ripple frequency;is the ripple phase.

As a preferable technical measure:

searching the fitting target expression by adopting a simulated annealing algorithm in a given estimation parameter searching range;

the searching steps are as follows:

step 1: number of initialization iterations k, temperature parameter C_pAccuracy epsilon, cooling coefficient alpha, randomly generating a set of estimation parameters p_i；

Step 2: initial feasible solution p_iCalculating a fitting objective function value J (p)_i)；

And step 3: judgment of equilibrium Condition J (p)_i) If the epsilon is less than epsilon, turning to a step 6 if the epsilon is true, or turning to a step 4-5 if the epsilon is not true;

and 4, step 4: randomly generating a set of estimated parameters p in the neighborhood of the current solution_jCalculating its fitting objective function value J (p)_j)；

And 5: performing an acceptance criterion, if J (p)_j)≤J(p_i) Then receive p_jReturning to the step 2 for feasible solution; otherwise, judging the acceptance probabilityIf true, accept p_jIf the solution is feasible, returning to the step 2, otherwise, directly returning to the step 2;

step 6: if the iteration times are reached, stopping the iteration; reduction of temperature, C'_p＝αC_pGo back to step 2.

As a preferable technical measure:

in the fourth step, the simulation process specifically includes the following steps:

s1, logging in the system by a terminal manager;

s2, after logging in, the terminal manager inputs weather forecast conditions, load forecast conditions, direct current converter station control modes, system direct current bus voltage standard values and system direct current bus power standard values into the system;

s3, after data entry, running simulation to obtain a simulation result;

in the specific simulation process, a simscape power system toolbox in matlab/simulink software can be used for modeling according to the topological structure of the power distribution network through an existing component library in the toolbox, and then data in S2 is input to obtain a simulation result;

s4, comparing the simulation result with the reference range of the metering point;

if the simulation result is greatly different from the reference range of the metering point and no alarm information exists at the moment, the electric energy management layer sends information to a person in charge of the metering point through the server and informs the person to go to the position of the metering point to troubleshoot faults.

As a preferable technical measure:

a metering system of a medium and low voltage direct current transmission system applies the metering method of the medium and low voltage direct current transmission system, and comprises the following steps: the system comprises an acquisition layer, a data management layer and an electric energy management layer; the electric energy management, the calibration of the metering result and the safety alarm are realized;

the acquisition layer is used for acquiring system operation information and detecting the system operation condition and comprises an electric energy acquisition module and a communication module;

the electric energy acquisition module is used for acquiring electric energy information and establishing connection between a physical entity and a network through the communication module;

the electric energy acquisition module triggers an alarm when measuring out-of-limit voltage and current information;

the data management layer is used for completing the transmission, storage and type processing of data and is divided into two modules, namely a network service module and a storage module;

the network service module is used for reading the metering data transmitted by the acquisition layer and reading the alarm information of the electric energy acquisition module;

the storage module is used for storing the data read by the network service module;

the electric energy management layer is used for reading an instruction given by an operator, reading electric energy measured by the electric energy acquisition module, and further analyzing the running state and the charging condition of the direct current distribution network system;

the electric energy management layer is integrated with a simulation system, and is used for simulating a metering result by reading an instruction (such as environmental weather, load state and the like) given by an operator, and then comparing the metering result with the electric energy received by the acquisition system received by the electric energy management layer, so that the metering accuracy of the system is ensured.

According to the invention, through direct current metering, a wireless communication technology and a real-time simulation technology, a metering scheme for a medium and low voltage direct current transmission system is designed, electric energy management and metering result correction can be realized, and out-of-limit alarm of voltage and current can be realized, and the scheme is simple, practical, scientific and reasonable; the method can meet the requirements of scientific measurement of medium and low voltage direct current transmission systems of power grid companies and users.

As a preferable technical measure:

the electric energy acquisition module comprises a voltage divider, a current divider, a merging module and an electric energy metering module;

the electric energy metering module conforms to national standard GB/T33708-2017 and industrial standards DL/T1484-2015 and DL/T448-2016;

the voltage divider converts the direct-current voltage to be measured into voltage of 100V and the precision is 0.2 level;

the current divider converts the direct current to be measured into 20A current with the precision of 0.2 level;

setting a voltage and current out-of-limit alarm;

the communication module comprises an ESP8266 module and uploads the alarm event to the cloud end through a Wi-Fi network.

As a preferable technical measure:

the acquisition layer is connected with the data management layer through a communication module;

the communication module comprises but is not limited to infrared radio frequency, Bluetooth and ZigBee based communication;

the equipment in one data management layer corresponds to the equipment in one or more acquisition layers;

the network service module is provided with a network server and is used for reading the metering data and the alarm information transmitted by the acquisition layer equipment;

the storage module is provided with a database which adopts an open form and supports expansion and new equipment addition;

the network service module and the storage module are both written by java language, and data transmission is carried out by using https protocol and JSON or XML form.

As a preferable technical measure:

the electric energy management layer comprises a server, a computer and a data processing module;

each device in each power management layer corresponds to a plurality of devices in the data management layer;

the server reads data from the data management layer or the acquisition layer through a TCP/IP protocol;

the acquired data is transmitted to a data processing module to perform charging calculation and running state analysis on the metering system;

data processing modules include, but are not limited to: flicker analysis, ripple analysis, tip, peak, valley and level analysis and system direct current power flow analysis;

a terminal operator issues a system operation instruction through an analysis result, and the instruction is transmitted to the control station through the server, so that electric energy management is realized;

the computer loads a simulation system, and the simulation system simulates the running state of the system, so that a reference range of a metering result of a key metering point is given as a calibration standard of the metering result.

The specific operation process is that a terminal manager logs in the system; after logging in, a terminal manager inputs a weather forecast condition, a load forecast condition, a direct current converter station control mode, a system direct current bus voltage standard value and a system direct current bus power standard value into the system; after data are input, simulation software runs simulation, and the simulation result is the given value of the key metering point; if the difference between the measurement result and the simulation result is large and no alarm information exists at the moment, the electric energy management layer sends information to a person in charge of the measurement point through the server and informs the person to go to the position of the measurement point to troubleshoot faults;

compared with the prior art, the invention has the following beneficial effects:

through continuous exploration and test, the electric energy is measured by acquiring the actual operation information of the system; meanwhile, the electric energy can be effectively managed and the metering result can be corrected according to the collected information, and the scheme is scientific, reasonable and accurate; the method can meet the requirements of scientific measurement of medium and low voltage direct current transmission systems of power grid companies and users.

Drawings

Fig. 1 is a schematic diagram of a low voltage dc metering system according to the present invention.

Fig. 2 is a block diagram of the acquisition design of the low-voltage direct-current metering system of the invention.

Fig. 3 is a diagram of the architecture of the data management layer of the low voltage dc metering system according to the present invention.

Fig. 4 is a diagram of the architecture of the power management layer of the low voltage dc metering system according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

On the contrary, the invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details.

As shown in fig. 1 to 4, a metering method for a medium and low voltage dc power transmission system includes the following steps:

firstly, collecting system operation information and metering electric energy;

secondly, reading the collected metering data and equipment alarm information, and storing the data;

thirdly, processing the acquired data, analyzing the running state of the system and calculating the electric charge;

data processing includes, but is not limited to: flicker analysis, ripple analysis, tip, peak, valley and level analysis and system direct current power flow analysis; issuing a system operation instruction according to the data processing result, and transmitting the instruction to the control station through the server, thereby realizing electric energy management;

fourthly, simulating the running state of the system, and giving a reference range of the metering result of the key metering point as a calibration standard of the metering result; if the simulation result is larger than the reference range and no alarm information exists at the moment, sending information to a person in charge of the metering point where the simulation result is located, and informing the person to go to the position where the metering point is located to troubleshoot faults.

Through continuous exploration and test, the electric energy is measured by acquiring the actual operation information of the system; meanwhile, the electric energy can be effectively managed and the metering result can be corrected according to the collected information, and the scheme is scientific, reasonable and accurate; the method can meet the requirements of scientific measurement of medium and low voltage direct current transmission systems of power grid companies and users.

The invention applies the embodiment of the metering method of the medium and low voltage direct current transmission system, which comprises the following steps:

a metering system for a medium and low voltage dc power transmission system, comprising: the system comprises an acquisition layer, a data management layer and an electric energy management layer; the electric energy management, the calibration of the metering result and the safety alarm are realized;

the acquisition layer is used for acquiring system operation information and detecting the system operation condition and comprises an electric energy acquisition module and a communication module;

the electric energy acquisition module is used for acquiring electric energy information and establishing connection between a physical entity and a network through the communication module;

the electric energy acquisition module triggers an alarm when measuring out-of-limit voltage and current information;

the data management layer is used for completing the transmission, storage and type processing of data and is divided into two modules, namely a network service module and a storage module;

the network service module is used for reading the metering data transmitted by the acquisition layer and reading the alarm information of the electric energy acquisition module;

the storage module is used for storing the data read by the network service module;

the electric energy management layer is used for reading an instruction given by an operator, reading electric energy measured by the electric energy acquisition module, and further analyzing the running state and the charging condition of the direct current distribution network system;

the electric energy management layer is integrated with a simulation system, and is used for simulating a metering result by reading an instruction (such as environmental weather, load state and the like) given by an operator, and then comparing the metering result with the electric energy received by the acquisition system received by the electric energy management layer, so that the metering accuracy of the system is ensured.

According to the invention, through direct current metering, a wireless communication technology and a real-time simulation technology, a metering scheme for a medium and low voltage direct current transmission system is designed, electric energy management and metering result correction can be realized, and out-of-limit alarm of voltage and current can be realized, and the scheme is simple, practical, scientific and reasonable; the method can meet the requirements of scientific measurement of medium and low voltage direct current transmission systems of power grid companies and users.

A specific embodiment of the acquisition layer of the invention:

the collecting device in the collecting layer comprises an electric energy collecting module, a partial pressure module, a shunt module, a merging module and an electric energy metering module. The electric energy metering module conforms to the national standard GB/T33708-2017 and the industry standards DL/T1484-2015 and DL/T448-2016. The voltage divider converts the medium-voltage direct-current voltage to be measured into 100V, and the precision is 0.2 level; the current divider converts the direct current to be measured into 20A, and the precision is 0.2 level. Wherein, a voltage and current out-of-limit alarm is arranged. Wherein the acquisition layer device is provided with a communication module. The communication module selects an ESP8266 module, and the alarm event is uploaded to the cloud terminal through a Wi-Fi network.

Optionally, there are three schemes for calculating dc power in the acquisition layer, including an effective value method, an average value method, and an instantaneous value method, where T is sampling time and T is sampling start time₀The voltage sampling instantaneous value is u (t), the current sampling instantaneous value is i (t), and the expressions of the three calculation schemes are respectively:

the acquisition layer and the data management layer are connected through the wireless communication module. The wireless communication module can be selected but not limited to communication modes such as infrared radio frequency based, Bluetooth based, ZigBee based and the like.

The invention discloses a specific embodiment of a data management layer, which comprises the following steps:

the device in one data management layer can correspond to one or more acquisition layer devices. The data management layer device is divided into two parts, namely a network service part and a data storage part. The network service part is a server, and optionally, the invention selects RESTFul server. The server reads the metering data transmitted by the acquisition layer equipment. And simultaneously reading the alarm information of the acquisition layer equipment. The data storage part is used for realizing the function of storing and acquiring the acquired data in a longer event. The database adopts an open form and can support expansion and new equipment addition. The network service part and the data storage part are both written by java language, and data transmission is carried out by using https protocol and JSON or XML form.

The invention discloses a specific embodiment of an electric energy management layer, which comprises the following steps:

the electric energy management layer device is a processing terminal and comprises a server and a computer. Each power management layer device may correspond to a plurality of data management layer devices. The server reads data from the data management layer or the collection layer through a TCP/IP protocol. The collected data are transmitted to a data processing program in a computer for carrying out charging calculation and running state analysis on the metering system. The data processing program may include, but is not limited to: flicker analysis, ripple analysis, tip, peak, valley and flat analysis and system direct current power flow analysis. And a terminal operator can issue a system operation instruction through an analysis result, and the instruction is transmitted to the control station through the server, so that the electric energy management is realized.

In addition, the computer comprises a simulation program which can simulate the running state of the system and further give a reference range of the metering result of the key metering point as a calibration standard of the metering result.

The specific operation process is that a terminal manager logs in the system. After logging in, a terminal manager inputs a weather forecast condition, a load forecast condition, a direct current converter station control mode, a system direct current bus voltage standard value and a system direct current bus power standard value into the system. And after data are input, the simulation software runs simulation, and the simulation result is the given value of the key metering point. And if the difference between the reference range of the metering result and the simulation result is larger and no alarm information exists at the moment, the electric energy management layer sends information to a person in charge of the metering point through the server and informs the person to go to the position of the metering point to troubleshoot faults.

For flicker analysis and ripple analysis, the present embodiment samples a modeling fitting method. Taking voltage signal analysis as an example, let the voltage instantaneous value obtained by collection be U (T), and within the time T, the voltage flicker amplitude is Δ U, and the ripple amplitude U_mRipple frequency ω and ripple phase ofThe voltage expression in time T is:

the target is fit to estimate the parameters during T timeIf the absolute value of the difference between the estimated expression (4) and the sampled voltage is made as small as possible, the fitting target can be expressed as:

under the condition of a given estimation parameter search range, optionally, heuristic algorithms such as simulated annealing algorithm, genetic algorithm, particle swarm algorithm and the like can be used for searching.

Taking the simulated annealing algorithm as an example, the searching steps are as follows:

step 1: number of initialization iterations k, temperature parameter C_pAccuracy epsilon, cooling coefficient alpha, randomly generating a set of estimation parameters p_i。

Step 2: initial feasible solution p_iCalculating a fitting objective function value J (p)_i)。

And step 3: judgment of equilibrium Condition J (p)_i) If yes, go to step 6, otherwise go to step 4-5.

And 4, step 4: randomly generating a set of estimated parameters p in the neighborhood of the current solution_jCalculating its fitting objective function value J (p)_j)。

And 5: performing an acceptance criterion, if J (p)_j)≤J(p_i) Then receive p_jReturning to the step 2 for feasible solution; otherwise, judging the acceptance probabilityIf true, accept p_jAnd (5) returning to the step 2 for feasible solution, otherwise directly returning to the step 2.

Step 6: and if the iteration times are reached, stopping the iteration. Reduction of temperature, C'_p＝αC_pGo back to step 2.

The following principles should be followed in the type selection and site selection of the electric energy metering equipment of the acquisition layer:

1) the medium-voltage direct-current metering points are IV-type metering points because the electric energy metering device is below 10 kV. The 20kV bus belongs to a 10 kV-110 (66) kV trade settlement metering point, so the bus is a III-class metering point. But considering the integrity of the system, the system is convenient for uniform design and uniform installation, and the accuracy grade of the metering device is set to be the lowest 0.5 grade.

2) According to the related standard of direct current metering, rated voltages of the metering device are 100V, 350V, 500V and 700V, wherein 350V, 500V and 700V can be converted into 100V through a voltage divider; the calibration current is 20A, 50A, 100A, 200A, 500A, 100A or above, and is preferably connected by a shunt.

3) According to the relevant standard of an electric energy metering device, the metering current below 60A can be directly accessed, and the current transformer above 60A needs to be connected. Wherein, the maximum current of the direct access type electric energy meter is not more than 100A.

4) For a 10kV direct-current bus, the voltage needs to be converted into 100V through a voltage divider, and the accuracy of the voltage divider is 0.2 level; the current is converted into 20A through a shunt, and the accuracy of the shunt is 0.2 level.

5) For the photovoltaic side, a 100kW, 500V photovoltaic device is accessed as an example. Because the working current exceeds 100A, the current divider is selected to convert the current into 20A, and the accuracy of the current divider is 0.2 grade. For the voltage, 500V is in the direct access allowable range, but considering that the current measurement already adopts a mutual inductor, the voltage divider is also selected as the voltage part, the voltage is converted into 100V, and the accuracy of the voltage divider is 0.2 grade.

6) For the energy storage side, a 250kW 500V energy storage device is accessed as an example. Similar to photovoltaic devices, a current divider is selected to convert the current into 20A, and the accuracy of the current divider is 0.2 level. For voltage, a voltage divider is selected, the voltage is converted into 100V, and the accuracy of the voltage divider is 0.2 level.

7) For low-voltage load, a 500kW +/-375V direct-current charging pile is accessed as an example. The current is converted into 20A by selecting a current divider, and the accuracy of the current divider is 0.2 grade. For voltage, a voltage divider is selected, the voltage is converted into 100V, and the accuracy of the voltage divider is 0.2 level.

8) For the metering point of the medium-voltage direct-current bus, the metering point should be selected behind a direct-current filter of the converter station, so as to reduce the influence of harmonic waves on direct-current metering.

9) And selecting a photovoltaic or energy storage grid connection point for a photovoltaic side or energy storage side low-voltage direct current bus metering point. If the photovoltaic or energy storage property right belongs to a third party, the photovoltaic or energy storage property right is arranged at the property right boundary. And selecting a low-voltage direct-current bus metering point on a low-voltage load side at a load grid-connected point.

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.

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.