CN102914694B - There is the intelligent electric meter of load measurement function - Google Patents

Abstract

There is the intelligent electric meter of load measurement function, the input of the voltage and current signal utilizing intelligent electric meter to be provided with, signal condition, sampling, A/D conversion, store, communication interface and microprocessor, obtain load model to survey and distinguish required voltage, electric current, the data such as meritorious, idle, according to ammeter place electric pressure, administrative Overload Class, set up appropriate load model and carry out continual load model structure and parameter identification work in 24 hours, by Automatic meter reading system intelligent electric meter to be measured and the load-related information layering that picks out is collected and concentrates Shang Song main website; Thus provide basic data endlessly for load modeling, load prediction.Load model is surveyed and is distinguished that algorithm is transplanted in intelligent electric energy meter by the present invention, the voltage of electric energy meter, the electric current input quantity load model structure and parameter to access is utilized to carry out on-line identification, survey distinguishes that result delivers to main website by Automatic meter reading system, realizes the wide area load modeling of power system load.

Description

There is the intelligent electric meter of load measurement function

Technical field

The invention belongs to Power System and its Automation technical field, relate to a kind of intelligent electric meter.

Background technology

Modeling for Electric Loads be one very important while also very difficult work, the accuracy of load model has very important impact to electric power system design, analysis and calculation, particularly has direct impact to the result of power system safety and stability analysis.

The difficult point of load model research is that load also exists the features such as randomness, time variation, dispersiveness, diversity and uncontinuity, for a long time, domestic and international experts and scholars have carried out research extensively and profoundly, totally define four kinds of methods, Component Based, Measurement-based approach, fault simulation method and mixing method, these methods all achieve good effect at different aspect.But electric system is the system of development, along with the change of system scale, the use of new technical equipment, the introducing of distributed energy all bring lot of challenges to load modeling work.

In fact, any one load modeling method all needs to have the composition of load and proportion to understand accurately, and have enough samples to ensure the effect of modeling, and a major issue is for a long time exactly that load statistical data is incomplete, reason to be the acquisition of statistical data be a huge engineering.The acquisition of load composition inventory generally derives from the sales check of electrical equipment, user declares document etc.; Load uses data source in the periodic measurement of consumer; According to user's power consumption form, in order to determine the proportion of each type load in overall.Because load is of a great variety, enormous amount and constantly increase change, geographically have simultaneously and have dispersiveness, a statistical work has also been difficult to once in a while, says nothing of regular statistics, even if complete statistical work, but the randomness of load also has no way of holding.

Electric energy meter is electric system electric energy measuring equipment, be a kind of distribution the most extensively, the most basic electric power data acquisition, measurement and processing unit, and the at all levels all useful various uses electric energy meter meter of system, from the electric supply meter of least significant end, power distributing meter to the feeder line table, Source of Gateway Meter etc. of plant stand.

Intelligent electric meter is the emphasis that global intelligent grid is built, along with carrying out of intelligent grid construction, the development of intelligent electric meter and application also reach higher level, modern electric energy meter be integrate meritorious, reactive energy-meter, maximum demand meter, the several functions such as meritorious, reactive volt-ampere meter, power factor meter, frequency meter, voltage table, rate of qualified voltage table, electric energy quality monitor, noisy data registering instrument, load governor parameters of electric power comprehensive monitoring equipment.Not only can monitor and record electric parameter, a day typical load curve can also be formed, even can carry out some and control on the spot.A lot of ammeter all have employed high-performance MCU and dsp chip at present, and signal handling capacity unprecedentedly improves, and along with its computing power of development of technology will improve further, and price constantly declines, and this just makes ordinary electric meter have very high computing and processing power.The application of the technology such as power line communication, radio communication greatly facilitates again the development of Automatic meter reading system, and power department can realize remote auto by technological means such as power-line carrier communication (PLC) or GPRSs (GPRS) and copy power taking meter reading and relevant information.

Summary of the invention

The object of the invention is: the method to set up that a kind of intelligent electric meter is provided, intelligent electric meter is made to have load measurement function, transplant load model structure and parameter identification algorithm wherein, make ammeter have load model survey and distinguish function, by Automatic meter reading system by load-related information Shang Song main website, the wide area modeling of power system load can be realized.

The technical scheme that the present invention takes is: the intelligent electric meter with load measurement function, the input of the voltage and current signal utilizing intelligent electric meter to be provided with, signal condition, sampling, A/D changes, store, communication interface and microprocessor (being ready-made hardware resource substantially), obtain load model survey and distinguish required voltage, electric current, meritorious, the data such as idle, according to ammeter place electric pressure, administrative Overload Class, set up appropriate load model and carry out continual load model structure and parameter identification work in 24 hours, by Automatic meter reading system by the relevant information Shang Song load modeling main website added up and pick out, thus be load modeling, load prediction provides basic data endlessly.

By Automatic meter reading system intelligent electric meter to be measured and the load-related information layering that picks out is collected and concentrates Shang Song main website.

Load model is surveyed and distinguishes that algorithm is transplanted in intelligent electric energy meter, utilize the voltage of electric energy meter, the electric current input quantity load model structure and parameter to access to carry out on-line measurement and identification.Realize the identification of load statistics and model parameter; Finally, by electric meter data collecting system, statistics and identification information are carried out collecting and arranging, comprehensive statistics is carried out to the load-related information of all each levels, analyzes and check, final acquisition load composition, proportion and time response etc., thus set up the load model tallied with the actual situation.

The key content of power system load modeling comprises model structure and parameter identification two aspects, and in general, load composition simply then easily determines rational model structure, and its parameter of model rational in infrastructure is just easy identification also, and accuracy is also high.Follow this thinking, first such as, for certain block intelligent electric meter, one family user typical load, add up the composition of its typical consumer, from physical essence and the mechanism of load, set up the load model tallied with the actual situation; Secondly, in intelligent electric meter handling procedure, implant suitable Online statistics modeling algorithm, realize the identification of load statistics and model parameter; Finally, by electric meter data collecting system, statistics and identification information are carried out collecting and arranging, comprehensive statistics is carried out to the load-related information of all each levels, analyzes and check, final acquisition load composition, proportion and time response etc., thus set up the load model tallied with the actual situation.Step is as follows:

1) algorithm picks:

Because intelligent electric meter is widely distributed, from probability, the intelligent electric meter of different regions and different electric pressure always experiences various disturbance, therefore, can formulate different identification schemes for different situations.The survey such as can carrying out static model in the larger area of some voltage fluctuation or electric pressure (voltage slowly fluctuates more than 10%) is distinguished, the survey can carrying out dynamic model for the area (voltage rapid fluctuations is more than 5%) that disturbance is multiple is distinguished.Threshold is differentiated by arranging certain disturbance, system disturbance mode can be identified, the model survey carrying out different modes is distinguished, and for more susceptible condition, voltage fluctuation actual being difficult to reaches above-mentioned scope, but voltage likely often runs into, therefore for this more generally situation at the Rapid Variable Design of (generally about 2%) among a small circle, the discrimination method of " first dynamic rear quiet " can be adopted, obtain dynamic and static state parameter simultaneously.

Be provided with load model and parameter to survey and know algoritic module, load model and parameter are surveyed and are known algoritic module and perform following flow process: the static nature coefficient obtaining load from dynamic model.First, dynamic model is adopted to go to describe load; Secondly when voltage and frequency and initial value depart from very little, can by static model linearization, adopt the method for this " first dynamic rear quiet; to be association of activity and inertia ", static nature coefficient can be obtained very easily by the dynamic model of identification gained, increase calculated amount hardly can obtain dynamic model and static model simultaneously, this algorithm is very suitable for the on-line identification of voltage intelligent electric meter in (about 2%) Rapid Variable Design situation among a small circle.

2) communication interface: the Automatic meter reading system Content of Communication expanding intelligent electric meter, increases the content that load model is relevant, is convenient to reception and the statistics of load modeling main website.

The invention has the beneficial effects as follows:

1) the present invention utilizes the resources such as the existing hardware of intelligent electric meter, communication, network, and coverage rate is the widest, does not have blind spot, does not increase additional hardware equipment investment.

2) the present invention can build wide area load modeling system, can be user and provides basic load data endlessly, thus promote carrying out of every research work.

3) the invention solves load statistical work that is in the past extremely important to load modeling but that be simultaneously difficult to again, and the load realizing 24 hours continual wide areas adds up and work is distinguished in survey, establishes permanent mechanism.

4) the various achievements in research that load modeling is in the past formed can be inherited and use.

The invention discloses and a kind ofly there is load model survey and distinguish the intelligent electric meter technical scheme of function, load model is surveyed and is distinguished that algorithm is transplanted in intelligent electric energy meter by the program, the voltage of electric energy meter, the electric current input quantity load model structure and parameter to access is utilized to carry out on-line identification, survey distinguishes that result delivers to main website by Automatic meter reading system, realizes the wide area load modeling of power system load.

Accompanying drawing explanation

Fig. 1 has the intelligent electric meter schematic diagram of load model structure and parameter discriminating function.

Embodiment

1) algorithm picks: according to the load modeling method of aforesaid " first dynamic rear quiet, to be association of activity and inertia ", its expression formula is:

The formula of dynamic model is as follows:

$\mathrm{\ΔP}=(\mathrm{dP}/\mathrm{dU}){|}_{\stackrel{U=U_0}{f=f_0}}\mathrm{\ΔU}+(\mathrm{dP}/\mathrm{df}){|}_{\underset{f=f_0}{U=U_0}}\mathrm{\Δf}$

$\mathrm{\ΔQ}=(\mathrm{dQ}/\mathrm{dU}){|}_{\stackrel{U=U_0}{f=f_0}}\mathrm{\ΔU}+(\mathrm{dQ}/\mathrm{df}){|}_{\underset{f=f_0}{U=U_0}}\mathrm{\Δf}---\left(1\right)$

That is:

$\left[\begin{array}{c}\mathrm{\ΔP}\\ \mathrm{\ΔQ}\end{array}\right]=\left[\begin{array}{c}\mathrm{dP}/\mathrm{dU}\mathrm{dP}/\mathrm{df}\\ \mathrm{dQ}/\mathrm{dUdQ}/\mathrm{df}\end{array}\right]\left[\begin{array}{c}\mathrm{\ΔU}\\ \mathrm{\Δf}\end{array}\right]---\left(2\right)$

Wherein Δ U, Δ f are voltage and frequency is input variable, and Δ P, Δ Q are meritorious and idle is output variable.

Secondly, (voltage and frequency are changing among a small circle) dynamic model deteriorates to static model under steady state conditions, a reactor, and its state equation is:

$\frac{\mathrm{dX}}{\mathrm{dt}}=\mathrm{AX}+\mathrm{BV}$

Y＝CX+DV （3）

Wherein:

X: state vector

Y: output state vector

V: control vector

A: coefficient of regime matrix

B: control coefrficient matrix

C: output state matrix of coefficients

D: export control coefrficient matrix

According to the physical essence of load, in dynamic model, each variable derivative is zero namely obtain static model, order: $\frac{\mathrm{dX}}{\mathrm{dt}}=0,$ Can obtain:

Y＝[-CA ^-1B+D]V （4）

Wherein: Y=[Δ P, Δ Q] ^t, V=[Δ U, Δ f] ^t

Comparison expression (2) and (4) can obtain:

$\left[\begin{array}{cc}\mathrm{dP}/\mathrm{dU}& \mathrm{dP}/\mathrm{df}\\ \mathrm{dQ}/\mathrm{dU}& \mathrm{dQ}/\mathrm{df}\end{array}\right]=-{\mathrm{CA}}^{-1}B+D---\left(5\right)$

And static nature coefficient is:

$p_u=(\mathrm{dP}/\mathrm{dU})\frac{U_0}{P_0},p_f=(\mathrm{dP}/\mathrm{df})\frac{f_0}{P_0}$

$q_u=(\mathrm{dQ}/\mathrm{dU})\frac{U_0}{Q_0},q_f=(\mathrm{dQ}/\mathrm{df})\frac{f_0}{Q_0}---\left(6\right)$

Wherein p _u, p _f, q _u, q _ffor Static Load characteristic coefficient, and dP/dU, dP/df, dQ/dU, dQ/df can be tried to achieve by dynamic model, from dynamic model, so just obtain the static nature coefficient of load.

2) program portable: program according to above-mentioned model, be transplanted in the central microprocessing unit (MCU) of ammeter, obtain the parameter such as the voltage of electric energy computation chip, electric current, meritorious, idle, frequency, power factor, complete the exploitation of the intelligent electric meter with load model structure and parameter discriminating function.

3) ammeter is installed.

Claims (2)

1. there is the intelligent electric meter of load measurement function, it is characterized in that: the input of the voltage and current signal utilizing intelligent electric meter to be provided with, signal condition, sampling, A/D changes, store, communication interface and microprocessor, obtain load model survey and distinguish required voltage, electric current, meritorious, idle data, according to ammeter place electric pressure, administrative Overload Class, set up appropriate load model and carry out continual load model structure and parameter identification work in 24 hours, by Automatic meter reading system intelligent electric meter to be measured and the load-related information layering that picks out is collected and concentrates Shang Song main website, thus provide basic data endlessly for load modeling, load prediction, load model is surveyed and distinguishes that algorithm is transplanted in intelligent electric energy meter, utilize the voltage of electric energy meter, the electric current input quantity load model structure and parameter to access to carry out on-line measurement and identification, realize the identification of load statistics and model parameter, finally, by electric meter data collecting system, statistics and identification information are carried out collecting and arranging, comprehensive statistics is carried out to the load-related information of all each levels, analyzes and check, final acquisition load composition, proportion and time response, thus set up the load model tallied with the actual situation.

2. the intelligent electric meter with load measurement function according to claim 1, it is characterized in that: the content of power system load modeling comprises model structure and parameter identification two aspects, first intelligent electric meter, add up the composition of its typical consumer, from physical essence and the mechanism of load, set up the load model tallied with the actual situation; Secondly, in intelligent electric meter handling procedure, implant suitable Online statistics modeling algorithm, realize the identification of load statistics and model parameter; Finally, by electric meter data collecting system, statistics and identification information are carried out collecting and arranging, comprehensive statistics is carried out to the load-related information of all each levels, analyzes and check, final acquisition load composition, proportion and time response, thus set up the load model tallied with the actual situation; Step is as follows:

1) algorithm picks:

Different identification schemes is formulated for different situations; The survey carrying out static model when voltage slowly fluctuates more than 10% is distinguished; Voltage rapid fluctuations is more than 5%, and the survey carrying out dynamic model is distinguished; Differentiating threshold by arranging disturbance, identifying system disturbance mode, the model survey carrying out different modes is distinguished; Above-mentioned scope is reached to voltage fluctuation actual being difficult to, but voltage adopts the discrimination method of " first dynamic after quiet " when 2% Rapid Variable Design among a small circle, obtain dynamic and static state parameter simultaneously;

Be provided with load model and parameter to survey and know algoritic module, load model and parameter are surveyed and are known algoritic module and perform following flow process: the static nature parameter obtaining load from dynamic model; First, dynamic model is adopted to go to describe load; Secondly when voltage and frequency and initial value depart from very little, by static model linearization, adopt the method for this " first dynamic rear quiet; to be association of activity and inertia ", static nature coefficient is obtained very easily by the dynamic model of identification gained, increase calculated amount hardly can obtain dynamic model and static model simultaneously, this algorithm is very suitable for the on-line identification of voltage intelligent electric meter in Rapid Variable Design situation among a small circle;

2) communication interface: the Automatic meter reading system Content of Communication expanding intelligent electric meter, increases the content that load model is relevant, is convenient to reception and the statistics of load modeling main website;

3) formula of dynamic model is as follows:

$\mathrm{\ΔP}=(\mathrm{dP}/\mathrm{dU}){|}_{\underset{f=f_0}{U=U_0}}\mathrm{\ΔU}+(\mathrm{dP}/\mathrm{df}){|}_{\underset{f=f_0}{U=U_0}}\mathrm{\Δf}$

$\mathrm{\ΔQ}=(\mathrm{dQ}/\mathrm{dU}){|}_{\underset{f=f_0}{U=U_0}}\mathrm{\ΔU}+(\mathrm{dQ}/\mathrm{df}){|}_{\underset{f=f_0}{U=U_0}}\mathrm{\Δf}---\left(1\right)$

That is:

$\left[\begin{array}{c}\mathrm{\ΔP}\\ \mathrm{\ΔQ}\end{array}\right]=\left[\begin{array}{cc}\mathrm{dP}/\mathrm{dU}& \mathrm{dP}/\mathrm{df}\\ \mathrm{dQ}/\mathrm{dU}& \mathrm{dQ}/\mathrm{df}\end{array}\right]\left[\begin{array}{c}\mathrm{\ΔU}\\ \mathrm{\Δf}\end{array}\right]---\left(2\right)$

Wherein Δ U, Δ f are voltage and frequency is input variable, and Δ P, Δ Q are meritorious and idle is output variable;

Secondly, namely voltage and frequency dynamic model when changing among a small circle deteriorate to static model under steady state conditions, a reactor, and its state equation is:

$\frac{\mathrm{dX}}{\mathrm{dt}}=\mathrm{AX}+\mathrm{BV}$

Y＝CX+DV (3)

Wherein:

X: state vector

Y: output state vector

V: control vector

A: coefficient of regime matrix

B: control coefrficient matrix

C: output state matrix of coefficients

D: export control coefrficient matrix

According to the physical essence of load, in dynamic model, each variable derivative is zero namely obtain static model, order:

$\frac{\mathrm{dX}}{\mathrm{dt}}=0,$ Can obtain:

Y＝[-CA ^-1B+D]V (4)

Wherein: Y=[Δ P, Δ Q] ^t, V=[Δ U, Δ f] ^t

Comparison expression (2) and (4) can obtain:

$\left[\begin{array}{cc}\mathrm{dP}/\mathrm{dU}& \mathrm{dP}/\mathrm{df}\\ \mathrm{dQ}/\mathrm{dU}& \mathrm{dQ}/\mathrm{df}\end{array}\right]=-{\mathrm{CA}}^{-1}B+D---\left(5\right)$

And static nature coefficient is:

$p_u=(\mathrm{dP}/\mathrm{dU})\frac{U_0}{P_0},p_f=(\mathrm{dP}/\mathrm{df})\frac{f_0}{P_0}$

$q_u=(\mathrm{dQ}/\mathrm{dU})\frac{U_0}{Q_0},q_f=(\mathrm{dQ}/\mathrm{df})\frac{f_0}{Q_0}---\left(6\right)$

Wherein p _u, p _f, q _u, q _ffor Static Load characteristic coefficient, and dP/dU, dP/df, dQ/dU, dQ/df can be tried to achieve by dynamic model, from dynamic model, so just obtain the static nature coefficient of load.