CN105893742A - Loss reduction quantitative empirical method for energy-saving transformer based on electricity quantity loss amortized computation - Google Patents

Abstract

The invention discloses a loss reduction quantitative empirical method for an energy-saving transformer based on electricity quantity loss amortized computation and belongs to the field of power distribution network low-carbon power research. The loss reduction quantitative empirical method includes the following steps of 1, measuring of network electricity quantity losses; 2, collection of measuring point loads of the head segment of a circuit; 3, demonstration of the loss-reduction effect. The electricity quantity loss value is converted to the same benchmark, quantitative comparison of energy-saving electricity quantity is achieved, real energy-saving electricity quantity obtained after the energy-saving transformer is mounted can be obtained, the loss-reduction effect of the energy-saving transformer is quantified, it is beneficial to popularization of the energy-saving technology, and a theoretical basis is provided for energy conservation and emission reduction work of the nation.

Description

Energy-saving transformer loss reduction quantification demonstration method based on electric quantity loss conversion

Technical Field

The invention belongs to the field of low-carbon power research of a power distribution network, and particularly relates to a loss reduction quantification demonstration method of an energy-saving transformer based on electric quantity loss conversion.

Background

Global warming is one of the biggest challenges facing current human society. According to the latest global climate change scientific assessment report of the united nations, the total cost caused by climate change will cause the global GDP loss to be about 5%. China is a large carbon emission country, and a large part of carbon emission comes from energy departments, especially the power industry. In order to cope with global climate change, it is imperative to reduce network loss in the power grid.

China's distribution network has huge distribution capacity, and the distribution loss reaches 15% -20%, and some areas reach 30% more. The transformer loss in the power distribution network accounts for 30% -60% of the power distribution loss. The novel energy-saving transformer is used for replacing a high-loss transformer in the power distribution network, so that the transformer loss is greatly reduced, and the efficiency of the power distribution network is improved. However, at present, research on energy-saving transformers at home and abroad mainly focuses on the design of the energy-saving transformers or the estimation method of the energy-saving loss of the transformers. Although the research can promote the development of the energy-saving transformer, the research is mainly focused on the research and actual measurement of the energy-saving transformer, the research on the aspects of the energy-saving and loss-reducing influence of the power grid is mostly focused on the qualitative influence and the promotion scheme of various factors, the processing of related algorithms is rough, the research on key technologies for the large-scale application of the new technologies is lacked, and the popularization and application of the new energy-saving technologies and energy-saving products are greatly hindered.

Aiming at the problems of inconsistent power grid loss calculation methods and difficulty in quantizing energy-saving potential and effect, a quantitative evaluation and demonstration technology for real energy-saving electric quantity after an energy-saving transformer is adopted is urgently needed. For the problem that the power grid running states before and after the energy-saving transformer is installed are different, and therefore the obtained power loss values cannot be directly compared, the two different running states need to be subjected to the same reference processing. The real energy-saving electric quantity of the power grid after the energy-saving transformer is installed can be obtained only after normalization.

Therefore, the energy-saving transformer quantification demonstration method based on the electric quantity loss conversion is provided, and a certain technical support is provided for the construction of the energy-saving service system of the national power grid company.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a loss reduction quantization demonstration method of an energy-saving transformer based on electric quantity loss conversion, which converts an electric quantity loss value to the same reference and realizes the quantization comparison of energy-saving electric quantity.

A loss reduction quantification demonstration method of an energy-saving transformer based on electric quantity loss conversion comprises the following steps:

s1, measuring the network power consumption;

s2, collecting the load of the first measuring point of the line;

s3, the efficacy of reducing impairment is proved.

Preferably, the S1 is specifically: selecting any typical measurement day as the measurement day when the energy-saving transformer is not installed, and measuring to obtain the power grid loss delta Abefore; and selecting a measurement day after the transformer with the skill is installed, measuring to obtain power grid loss delta Aafter, and recording data of network active power Pi, reactive power Qi and network voltage Ui every 15 minutes at a first measurement point of a line of the power grid, wherein i is 0,1 and 2 … 95.

Preferably, the S2 is specifically: according to the standard selected in the typical measuring day in S1, data records of the typical measuring days of three uninstalled energy-saving transformers in the last three years are retrieved from the database, wherein the data records comprise three data records available at the first measuring point of the line of the power grid of the current level, and each record comprises the active electric quantity A of the whole day of the measuring day_aAll-day reactive power A_rAnd 96 groups of active power P, reactive power Q and network voltage U are collected to obtain interval values of three groups of shape coefficientsAndwherein,k ₁,k ₂,k ₃respectively representing the lower boundaries of the three sets of shape coefficient intervals,respectively representing the upper boundaries of the three sets of shape coefficient intervals.

Preferably, the interval value of the shape factor may be obtained on the basis of collecting the grid state every 15 minutes by:

s21, calculating the average value of the measured representative daily load current,

$I_{pj}=\stackrel{95}{\Σ}{I}_i/96---\left(1\right)$

in the formula: i is_i-load current value, I, representing the ith day period_pj-represents the average value of the daily load current;

s22, finding the maximum value of the shape coefficient interval:

if the current value I representing the daily load is actually measured in a certain period_iGreater than the average value of the load current I_pjThen take the maximum value of the load current in the periodSuch as I_iIs less than I_pjThen take the minimum value of the load current in the periodI _iTaking the average value I of the load current far from the actually measured representative day_pjThe maximum value of the shape coefficient interval can be obtained by obtaining the shape coefficient of the curve, and the mathematical expression is as follows:

$I_i^{\&prime;}=\left\{\begin{array}{cc}\stackrel{\&OverBar;}{I_i}& I_i\&GreaterEqual;I_{pj}\\ \underset{\&OverBar;}{I_i}& I_i<I_{pj}\end{array}\right.---\left(2\right)$

in the formula: i'_i-the load current value for the i-th time interval selected when the most strongly varying continuous load curve is formed;

the maximum value of the shape coefficient interval can be obtained by calculating the shape coefficient of the curve

$\stackrel{\&OverBar;}{k}=\sqrt{\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;2}/96}/\left(\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;}/96\right)---\left(3\right)$

S23, obtaining the minimum value of the shape coefficient interval:

if it is the minimum of the load in the periodI _iLess than the average load value I_pjThen get I_pjCalculating, otherwise, taking its minimum valueI _i(ii) a E.g. I for a certain period of time_iIs less than I_pjE.g. maximum load of the periodValue ofIs greater than I_pjThen get I_pjPerforming calculation, otherwise, taking the maximum valueThe average value I of the load current close to the actually measured representative day is obtained_pjThe most gradual continuous load curve is formed by the load values of (1):

in the formula: i ″)_i-the load current value for the i-th time interval selected when the most gently varying continuous load curve is formed;

the minimum value k of the shape coefficient interval can be obtained by calculating the shape coefficient of the curve:

$\underset{\&OverBar;}{k}=\sqrt{\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;\&prime;2}/96}/\left(\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;\&prime;}/96\right)---\left(5\right)$

the section K of the shape factor of the load curve can be obtained from the two equations:

$K=\&lsqb;\underset{\&OverBar;}{k},\stackrel{\&OverBar;}{k}\&rsqb;$

s24, obtaining a line equivalent resistor RLeq and a transformer equivalent resistor RTeq according to the level power grid network structure;

and S25, the grid active loss comprises the no-load loss and the line loss of the transformer, and for the historical data obtained in the S22, the grid active loss can be represented as follows:

$\begin{array}{c}{\mathrm{\&Delta;P}}_{total}=I_{eef}^2(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\\ =K^2\frac{A_a^2+A_r^2}{U_{av}^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\end{array}---\left(6\right)$

in the formula,. DELTA.P_totalIs the active loss of the grid, I_effThe Uav is the arithmetic mean value of 96 network voltages U in any recorded data, wherein the Uav is the total load current of the whole power distribution network; a. the_aActive power for measuring historical load at the head end of the line, A_rThe power consumption is the reactive power of the historical load of the first measuring point of the line, and P0 is the no-load loss of the transformer;

due to the fact thatIs an interval value, then Δ P_totalAlso applying interval representations, i.e.

$\begin{array}{c}{\mathrm{\&Delta;P}}_{total}=\&lsqb;{\left(\underset{\&OverBar;}{k}\right)}^2\frac{A_a^2+A_r^2}{U_{av}^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0,{\left(\stackrel{\&OverBar;}{k}\right)}^2\frac{A_a^2+A_r^2}{U_{av}^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\&rsqb;\\ =\&lsqb;\mathrm{\&Delta;}\underset{\&OverBar;}{P_{total}},\mathrm{\&Delta;}\stackrel{\&OverBar;}{P_{total}}\&rsqb;\end{array}---\left(7\right)$

S26, obtaining the grid active power loss interval values of the three groups of data obtained in S22 through the steps, namely obtaining the grid active power loss interval values of the three groups of data obtained in S22Is provided with The value of the interval of the active power loss of the power grid is determined asWhereinΔP _total1,ΔP _total2,ΔP_total3Respectively represents the lower limit values of the active loss intervals of the three groups of power grids,respectively represents the upper limit values of the active loss interval values of the three groups of power grids,ΔP _totaljthree groups of any one group of the power grid active lossA lower consumption interval value limit, wherein j is 1,2, 3;the active loss interval value of the power grid is an upper limit value of any three groups, wherein j is 1,2 and 3. Delta P_totalThe active loss value of the power grid is the value,Δ P _totalthe lower limit value of the active loss interval value of the power grid,the upper limit value of the interval value of the active loss of the power grid is set;

s27, obtaining 96 sets of grid active power loss values according to the data (i is 0,1,2 …) of 96 sets of grid active power Pi, reactive power Qi and network voltage Ui obtained by measuring after installing the energy-saving transformer in S1, and setting the values as the values

${\mathrm{\&Delta;P}}_{afteri}=\frac{P_i^2+Q_i^2}{U_i^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_{0i},(i=0,1,2...95)---\left(8\right)$

ΔP_afteriIs any group of power grid active power loss values, wherein i is 0,1,2 … 95, P_0iIs any oneA transformer loss value in the grid, wherein i is 0,1,2 … 95;

s28, obtaining 96 groups of power grid active power loss values delta P through the step S27_afteriInterval value of active power loss of power gridFurther, each Δ P is obtained_afteriUpper limit value ofAnd lower limit valueThe specific calculation formula is as follows:

$\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{afteri}}={\mathrm{\&Delta;P}}_{afteri}+\frac{1}{2}(\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}-\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}})---\left(9\right)$

$\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{afteri}}={\mathrm{\&Delta;P}}_{afteri}-\frac{1}{2}\left(\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}-\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}\right)---\left(10\right)$

s29, drawing 96Connecting the values by line segments to obtain the upper limit curve of the active power loss of the power grid, and similarly connecting 96 active power loss upper limit curvesΔP _afteriThe values are connected by line segments to obtain a power grid active power loss lower limit curve, and finally, a power grid electric quantity loss conversion interval value is obtained through calculation

Preferably, the S3 is specifically: converting the power grid loss and the power grid electric quantity loss into an interval value measured by installing the energy-saving transformerAnd comparing to obtain the real energy-saving electric quantity.

The technical scheme of the invention has the following beneficial effects:

according to the loss reduction quantification demonstration method for the energy-saving transformer based on electric quantity loss conversion, provided by the invention, the quantitative comparison of the energy-saving electric quantity is realized by converting the electric quantity loss value to the same reference, so that the real energy-saving electric quantity after the energy-saving transformer is installed can be obtained, the popularization of an energy-saving technology is facilitated by quantifying the loss reduction effect of the energy-saving transformer, and a theoretical basis is provided for the national energy-saving and emission-reduction work.

Drawings

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

FIG. 1 is a flow chart of a loss reduction quantization demonstration method of an energy-saving transformer based on electric quantity loss conversion according to the present invention;

Detailed Description

In order to clearly understand the technical solution of the present invention, a detailed structure thereof will be set forth in the following description. It is apparent that the specific implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, and other embodiments are possible in addition to the embodiments described in detail.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

With reference to fig. 1, the method for loss reduction quantization demonstration of an energy-saving transformer based on electric quantity loss conversion is disclosed, and comprises the following steps:

s1, measuring the network power consumption; selecting any typical measurement day as the measurement day when the energy-saving transformer is not installed, and measuring to obtain the power grid loss delta Abefore; and selecting a measurement day after the transformer with the skill is installed, measuring to obtain power grid loss delta Aafter, and recording data of network active power Pi, reactive power Qi and network voltage Ui every 15 minutes at a first measurement point of a line of the power grid, wherein i is 0,1 and 2 … 95.

S2, collecting the load of the first measuring point of the line; according to the standard selected in the typical measuring day in S1, data records of the typical measuring days of three uninstalled energy-saving transformers in the last three years are retrieved from the database, wherein the data records comprise three data records available for the first measuring point of the current-level power grid line, and each record comprises the measuring dayAll-day active electric quantity A_aAll-day reactive power A_rAnd 96 groups of active power P, reactive power Q and network voltage U are collected to obtain interval values of three groups of shape coefficientsAndwherein,k ₁,k ₂,k₃respectively representing the lower boundaries of the three sets of shape coefficient intervals,respectively representing the upper boundaries of the three sets of shape coefficient intervals.

The interval value of the shape factor can be obtained according to the following steps, wherein the following steps are carried out on the basis of acquiring the power grid state every 15 minutes:

s21, calculating the average value of the measured representative daily load current,

$I_{pj}=\stackrel{95}{\&Sigma;}{I}_i/96---\left(1\right)$

in the formula: i is_i-load current value, I, representing the ith day period_pj-represents the average value of the daily load current;

s22, finding the maximum value of the shape coefficient interval:

if the current value I representing the daily load is actually measured in a certain period_iGreater than the average value of the load current I_pjThen take the maximum value of the load current in the periodSuch as I_iIs less than I_pjThen take the minimum value of the load current in the periodI _iTaking the average value I of the load current far from the actually measured representative day_pjThe maximum value of the shape coefficient interval can be obtained by obtaining the shape coefficient of the curve, and the mathematical expression is as follows:

$I_i^{\&prime;}=\left\{\begin{array}{cc}\stackrel{\&OverBar;}{I_i}& I_i\&GreaterEqual;I_{pj}\\ \underset{\&OverBar;}{I_i}& I_i<I_{pj}\end{array}\right.---\left(2\right)$

in the formula: i'_i-the load current value for the i-th time interval selected when the most strongly varying continuous load curve is formed;

the maximum value of the shape coefficient interval can be obtained by calculating the shape coefficient of the curve

$\stackrel{\&OverBar;}{k}=\sqrt{\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;2}/96}/\left(\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;}/96\right)---\left(3\right)$

S23, obtaining the minimum value of the shape coefficient interval:

if it is the minimum of the load in the periodI _iLess than the average load value I_pjThen get I_pjCalculating, otherwise, taking its minimum valueI _i(ii) a E.g. I for a certain period of time_iIs less than I_pjE.g. maximum value of load in the periodIs greater than I_pjThen get I_pjPerforming calculation, otherwise, taking the maximum valueThe average value I of the load current close to the actually measured representative day is obtained_pjThe most gradual continuous load curve is formed by the load values of (1):

in the formula: i ″)_i-the load current value for the i-th time interval selected when the most gently varying continuous load curve is formed;

the minimum value of the shape coefficient interval can be obtained by calculating the shape coefficient of the curvek：

$\underset{\&OverBar;}{k}=\sqrt{\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;\&prime;2}/96}/\left(\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;\&prime;}/96\right)---\left(5\right)$

The section K of the shape factor of the load curve can be obtained from the two equations:

$K=\&lsqb;\underset{\&OverBar;}{k},\stackrel{\&OverBar;}{k}\&rsqb;$

s24, obtaining a line equivalent resistor RLeq and a transformer equivalent resistor RTeq according to the level power grid network structure;

and S25, the grid active loss comprises the no-load loss and the line loss of the transformer, and for the historical data obtained in the S22, the grid active loss can be represented as follows:

$\begin{array}{c}{\mathrm{\&Delta;P}}_{total}=I_{eef}^2(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\\ =K^2\frac{A_a^2+A_r^2}{U_{av}^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\end{array}---\left(6\right)$

in the formula,. DELTA.P_totalIs the active loss of the grid, I_effThe Uav is the arithmetic mean value of 96 network voltages U in any recorded data, wherein the Uav is the total load current of the whole power distribution network; a. the_aActive power for measuring historical load at the head end of the line, A_rThe power consumption is the reactive power of the historical load of the first measuring point of the line, and P0 is the no-load loss of the transformer;

due to the fact thatIs an interval value, then Δ P_totalAlso applying interval representations, i.e.

$\begin{array}{c}{\mathrm{\&Delta;P}}_{total}=\&lsqb;{\left(\underset{\&OverBar;}{k}\right)}^2\frac{A_a^2+A_r^2}{U_{av}^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0,{\left(\stackrel{\&OverBar;}{k}\right)}^2\frac{A_a^2+A_r^2}{U_{av}^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\&rsqb;\\ =\&lsqb;\mathrm{\&Delta;}\underset{\&OverBar;}{P_{total}},\mathrm{\&Delta;}\stackrel{\&OverBar;}{P_{total}}\&rsqb;\end{array}---\left(7\right)$

S26, obtaining the grid active power loss interval values of the three groups of data obtained in S22 through the steps, namely obtaining the grid active power loss interval values of the three groups of data obtained in S22Is provided with The value of the interval of the active power loss of the power grid is determined asWhereinΔP _total1,ΔP _total2,ΔP_total3Respectively represents the lower limit values of the active loss intervals of the three groups of power grids,respectively represents the upper limit values of the active loss interval values of the three groups of power grids,ΔP _totaljthe active loss interval value of the power grid is a lower limit value of any three groups, wherein j is 1,2 and 3;the active loss interval value of the power grid is an upper limit value of any three groups, wherein j is 1,2 and 3. Delta P_totalThe active loss value of the power grid is the value,Δ P _totalthe lower limit value of the active loss interval value of the power grid,the upper limit value of the interval value of the active loss of the power grid is set;

s27, obtaining 96 sets of grid active power loss values according to the data (i is 0,1,2 …) of 96 sets of grid active power Pi, reactive power Qi and network voltage Ui obtained by measuring after installing the energy-saving transformer in S1, and setting the values as the values

${\mathrm{\&Delta;P}}_{afteri}=\frac{P_i^2+Q_i^2}{U_i^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_{0i},(i=0,1,2...95)---\left(8\right)$

ΔP_afteriIs any group of power grid active power loss values, wherein i is 0,1,2 … 95, P_0iThe loss value of the transformer in any group of power grids, wherein i is 0,1,2 … 95;

s28, obtaining 96 groups of power grid active power loss values delta P through the step S27_afteriInterval value of active power loss of power gridFurther, each Δ P is obtained_afteriUpper limit value ofAnd lower limit valueThe specific calculation formula is as follows:

$\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{afteri}}={\mathrm{\&Delta;P}}_{afteri}+\frac{1}{2}(\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}-\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}})---\left(9\right)$

$\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{afteri}}={\mathrm{\&Delta;P}}_{afteri}-\frac{1}{2}\left(\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}-\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}\right)---\left(10\right)$

s29, drawing 96Connecting the values by line segments to obtain the upper limit curve of the active power loss of the power grid, and similarly connecting 96 active power loss upper limit curvesΔP _afteriThe values are connected by line segments to obtain a power grid active power loss lower limit curve, and finally, a power grid electric quantity loss conversion interval value is obtained through calculation

S3, loss reduction effect demonstration; the power grid loss and the power grid electric quantity loss measured by the energy-saving transformer are convertedCalculating interval valueAnd comparing to obtain the real energy-saving electric quantity.

The following 10kV line in northwest city is taken as a research object, and the equivalent resistance R of the distribution line_{Leq formula}Equal value resistance R of distribution transformer when equal to 8.9 (omega)_{Teq formula}The influence of No. 1 distribution transformer on the feeder loss after conversion to an energy-saving transformer was studied 6.17(Ω). Selecting typical measuring days without the energy-saving transformer as 9-month and 12-month days in 2013, and typical measuring days with the energy-saving transformer as 4-month and 12-month days in 2014. And taking the outlet side of the head end of the feeder line and all the distribution transformer low-voltage sides on the feeder line as measuring points.

(1) Measurement of network power loss

The electric quantity of the first section of the line is 19700kW & h and 20680kW & h respectively on the typical measurement days before and after the energy-saving transformer is installed, and the electric quantity of all distribution transformers on the line is 19089kW & h and 20158kW & h on the typical measurement days before and after the transformer is installed.

Therefore, the network loss △ A of typical measuring days before the energy-saving transformer is installed can be obtained_before611 kW.h, and the network loss of a typical measurement day after the energy-saving transformer is installed is △ A_after＝422kW·h。

(2) Line first segment measurement point load collection

1) Typical daily load of first-segment measuring point of line

The load states of the line head end measurement points on two typical measurement days before and after the installation of the energy-saving transformer are collected, as shown in table 1 below.

TABLE 1 head end measurement point load data

From the data collected on a typical measurement day after installation of the energy saving transformer, 96 sets of network loss values can be obtained as shown in table 2 below.

TABLE 2 instantaneous values of network loss after installation of energy-saving transformers

2) Historical load of first-segment measuring point of line

And (3) calling historical data records of the line head end measuring points of 3 month and 13 days, 3 month and 20 days and 3 month and 27 days in 2013 without the energy-saving transformer, as shown in the following table 3.

TABLE 3 historical load of first measurement point of line

(3) Syndrome of excess effect of reducing damage

Processing the data in the table 3 by using a shape coefficient solving method to obtain a shape coefficient interval value of three days in history; further obtain the power loss interval value of the network, as shown in table 4.

TABLE 4 historical three-day shape coefficient interval values and network power loss interval values

The active power loss interval value delta Ptotal of the power grid can be obtained as [97.847,105.668] kW.h.

Finally, the active power loss values of 96 groups of power grids after the energy-saving transformer is installed and the power loss interval values before the energy-saving technology is adopted in table 4, which are obtained according to table 2, can be obtained: the electric quantity loss conversion interval value of the power grid is [647, 668] kW.h.

Comparing the converted interval value of the electric quantity loss of the power grid with the typical measured daily network loss 422kW & h after the energy-saving transformer is installed: the lower limit 647kW & h of the power consumption conversion interval value of the power grid is larger than 422kW & h of the typical measurement day network loss after the energy-saving transformer is installed, and the correctness and the validity of the empirical algorithm can be verified, so that the actual energy-saving interval value of the 10kV network after the energy-saving transformer is installed in 4 months and 12 days is [225, 246] kW & h.

Finally, it should be noted that: although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can make modifications and equivalents to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is set forth in the claims appended hereto.

Claims (5)

1. A loss reduction quantification demonstration method of an energy-saving transformer based on electric quantity loss conversion is characterized by comprising the following steps:

s1, measuring the network power consumption;

s2, collecting the load of the first measuring point of the line;

s3, the efficacy of reducing impairment is proved.

2. The loss reduction quantization demonstration method for energy-saving transformer based on electric quantity loss conversion according to claim 1,the method is characterized in that S1 specifically includes the steps that any typical measurement day is selected as the measurement day when no energy-saving transformer is installed, and power grid loss △ A is measured_beforeMeasuring the power grid loss △ A by selecting the measuring day after the transformer is installed_afterMeanwhile, in the first measuring point of the line of the power grid of the current level, the active power P of the network is recorded every 15 minutes_iReactive power Q_iAnd network voltage U_iWherein i is 0,1,2 … 95.

3. The loss reduction quantization demonstration method based on electric quantity loss conversion energy-saving transformer according to claim 2, wherein the step S2 specifically comprises: according to the standard selected in the typical measuring day in S1, data records of the typical measuring days of three uninstalled energy-saving transformers in the last three years are retrieved from the database, wherein the data records comprise three data records available at the first measuring point of the line of the power grid of the current level, and each record comprises the active electric quantity A of the whole day of the measuring day_aAll-day reactive power A_rAnd 96 groups of active power P, reactive power Q and network voltage U are collected to obtain interval values of three groups of shape coefficientsAndwherein,k ₁,k ₂,k ₃respectively representing the lower boundaries of the three sets of shape coefficient intervals,respectively representing the upper boundaries of the three sets of shape coefficient intervals.

4. The method for performing loss reduction quantization on the basis of the electric quantity loss conversion energy-saving transformer according to claim 3, wherein the interval values of the shape coefficients are obtained according to the following steps, wherein the following steps are performed on the basis of collecting the power grid state every 15 minutes:

s21, calculating the average value of the measured representative daily load current,

$I_{\mathrm{pj}}=\stackrel{95}{\mathrm{\&Sigma;}}{I}_i/96---\left(1\right)$

in the formula: i is_i-load current value, I, representing the ith day period_pj-represents the average value of the daily load current;

s22, finding the maximum value of the shape coefficient interval:

if the current value I representing the daily load is actually measured in a certain period_iGreater than the average value of the load current I_pjThen take the maximum value of the load current in the periodSuch as I_iIs less than I_pjThen take the minimum value of the load current in the periodI _iTaking the average value I of the load current far from the actually measured representative day_pjThe maximum value of the shape coefficient interval can be obtained by obtaining the shape coefficient of the curve, and the mathematical expression is as follows:

$I_i^{\&prime;}=\left\{\begin{array}{cc}\stackrel{\&OverBar;}{I_i}& I_i\&GreaterEqual;I_{pj}\\ \underset{\&OverBar;}{I_i}& I_i<I_{pj}\end{array}\right.---\left(2\right)$

in the formula: i'_i-the load current value for the i-th time interval selected when the most strongly varying continuous load curve is formed;

the maximum value of the shape coefficient interval can be obtained by calculating the shape coefficient of the curve

$\stackrel{\&OverBar;}{k}=\sqrt{\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;2}/96}/(\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;}/96)---\left(3\right)$

S23, obtaining the minimum value of the shape coefficient interval:

if it is the minimum of the load in the periodI _iLess than the average load value I_pjThen get I_pjCalculating, otherwise, taking its minimum valueI _i(ii) a E.g. I for a certain period of time_iIs less than I_pjE.g. maximum value of load in the periodIs greater than I_pjThen get I_pjPerforming calculation, otherwise, taking the maximum valueThe average value I of the load current close to the actually measured representative day is obtained_pjThe most gradual continuous load curve is formed by the load values of (1):

in the formula: i ″)_i-the load current value for the i-th time interval selected when the most gently varying continuous load curve is formed;

the minimum value of the shape coefficient interval can be obtained by calculating the shape coefficient of the curvek：

$\underset{\&OverBar;}{k}=\sqrt{\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;\&prime;2}/96}/(\underset{i=0}{\overset{95}{\&Sigma;}}{I}_i^{\&prime;\&prime;}/96)---\left(5\right)$

The section K of the shape factor of the load curve can be obtained from the two equations:

$K=\&lsqb;\underset{\&OverBar;}{k},\stackrel{\&OverBar;}{k}\&rsqb;$

s24, obtaining a line equivalent resistor RLeq and a transformer equivalent resistor RTeq according to the level power grid network structure;

and S25, the grid active loss comprises the no-load loss and the line loss of the transformer, and for the historical data obtained in the S22, the grid active loss can be represented as follows:

$\begin{array}{c}{\mathrm{\&Delta;P}}_{total}=I_{eff}^2(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_0\\ =K^2\frac{A_a^2+A_r^2}{U_{av}^2}\left(R_{Leq}+R_{Teq}\right)+\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{P}_0\end{array}---\left(6\right)$

in the formula,. DELTA.P_totalIs the active loss of the grid, I_effThe Uav is the arithmetic mean value of 96 network voltages U in any recorded data, wherein the Uav is the total load current of the whole power distribution network; a. the_aActive power for measuring historical load at the head end of the line, A_rThe power consumption is the reactive power of the historical load of the first measuring point of the line, and P0 is the no-load loss of the transformer;

due to the fact thatIs a value of one interval, and the interval value,then Δ P_totalAlso applying interval representations, i.e.

$\begin{array}{c}{\mathrm{\&Delta;P}}_{total}=\&lsqb;{\left(\underset{\&OverBar;}{k}\right)}^2\frac{A_a^2+A_r^2}{U_{av}^2}\left(R_{Leq}+R_{Teq}\right)+\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{P}_0,{\left(\stackrel{\&OverBar;}{k}\right)}^2\frac{A_a^2+A_r^2}{U_{av}^2}\left(R_{Leq}+R_{Teq}\right)+\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{P}_0\&rsqb;\\ =\&lsqb;\mathrm{\&Delta;}\underset{\&OverBar;}{P_{total}},\mathrm{\&Delta;}\stackrel{\&OverBar;}{P_{total}}\&rsqb;\end{array}---\left(7\right)$

S26, obtaining the grid active power loss interval values of the three groups of data obtained in S22 through the steps, namely obtaining the grid active power loss interval values of the three groups of data obtained in S22Is provided with The value of the interval of the active power loss of the power grid is determined asWhereinΔP _total1,ΔP _total2,ΔP_total3Respectively represents the lower limit values of the active loss intervals of the three groups of power grids,respectively represents the upper limit values of the active loss interval values of the three groups of power grids,ΔP _totaljthe active loss interval value of the power grid is a lower limit value of any three groups, wherein j is 1,2 and 3;the active loss interval value of the power grid is an upper limit value of any three groups, wherein j is 1,2 and 3. Delta P_totalThe active loss value of the power grid is the value,Δ P _totalthe lower limit value of the active loss interval value of the power grid,active for the gridAn upper limit value of the loss interval value;

s27, obtaining 96 sets of grid active power loss values according to the data (i is 0,1,2 …) of 96 sets of grid active power Pi, reactive power Qi and network voltage Ui obtained by measuring after installing the energy-saving transformer in S1, and setting the values as the values

${\mathrm{\&Delta;P}}_{afteri}=\frac{P_i^2+Q_i^2}{U_i^2}(R_{Leq}+R_{Teq})+\underset{i=1}{\overset{m}{\&Sigma;}}{P}_{0i},(i=0,1,2...95)---\left(8\right)$

ΔP_afteriIs any group of power grid active power loss values, wherein i is 0,1,2 … 95, P_0iThe loss value of the transformer in any group of power grids, wherein i is 0,1,2 … 95;

s28, obtaining 96 groups of power grid active power loss values delta P through the step S27_afteriInterval value of active power loss of power gridFurther, each Δ P is obtained_afteriUpper limit value ofAnd lower limit valueThe specific calculation formula is as follows:

$\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{afteri}}={\mathrm{\&Delta;P}}_{afteri}+\frac{1}{2}(\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}-\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}})---\left(9\right)$

$\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{afteri}}={\mathrm{\&Delta;P}}_{afteri}-\frac{1}{2}(\stackrel{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}}-\underset{\&OverBar;}{{\mathrm{\&Delta;P}}_{total}})---\left(10\right)$

s29, drawing 96Connecting the values by line segments to obtain the upper limit curve of the active power loss of the power grid, and similarly connecting 96 active power loss upper limit curvesΔ P _afteriThe values are connected by line segments to obtain a power grid active power loss lower limit curve, and finally, a power grid electric quantity loss conversion interval value is obtained through calculation

5. The loss reduction quantization demonstration method for the energy-saving transformer based on electric quantity loss conversion according to claim 4, wherein the step S3 specifically comprises: converting the power grid loss and the power grid electric quantity loss into an interval value measured by installing the energy-saving transformerAnd comparing to obtain the real energy-saving electric quantity.