CN106249044A - A kind of replacing based on root mean square transformator saves the monolateral measuring method of quantity of electricity - Google Patents

Abstract

The invention discloses a root-mean-square-based method for unilaterally measuring electricity saved by transformer replacement, which comprises the following steps: 1. Determining the energy-saving replacement project boundary, project base period, statistical reporting period, and typical work cycle; 2. On one side of the transformer Install voltage transformers, current transformers, and special meters that can set parameters and calculate power savings; 3. Before the implementation of the transformer replacement project, measure the transformer current and voltage, no-load loss, load loss, rated capacity, Parameters such as maximum load power; 4. Measurement of transformer current and voltage, no-load loss, load loss, rated capacity, and maximum load power parameters during the typical working cycle of the statistical reporting period; 5. Continuous calculation of root mean square voltage influence coefficient and root mean square current Influence coefficient; 6. Calculation of power saving. The invention has the advantages of simplifying the measurement process, saving the measurement cost, accurate measurement results and the like.

Description

A root-mean-square-based method for unilateral measurement of power saved by transformer replacement

technical field

The invention relates to a transformer power measurement method, in particular to a root-mean-square-based method for unilaterally measuring electric power saved by transformer replacement, and the measurement method belongs to the technical field of transformer measurement.

Background technique

In the power system, distribution transformers, as the main equipment for voltage, current and power conversion, are very large in number and are increasing year by year. Although the loss of each transformer is small, due to its huge base and long-term operation, the total loss caused by distribution transformers every year is very alarming. At the same time, older transformers are still used in some areas, and their loss is significantly higher than that of new transformers. Therefore, it is an inevitable choice to improve the overall energy efficiency level of the power grid and reduce energy loss by replacing new distribution transformers. In order to carry out transformer replacement in an orderly and reasonable manner, analyze the economic benefits of the replacement project, and guide the planning and design of power transformer replacement, it is necessary to measure and calculate the power saving before and after transformer replacement.

There is no unified reference standard for the measurement of electricity saved by transformer replacement. The Chinese invention patent application with the application publication number CN103018584A discloses a measurement and verification method for power boost transformation to save power and electricity. The invention patent measures the operating parameters of the transformer before and after transformation by installing measuring devices on both sides of the transformer , to calculate the power saving. The Chinese invention patent application with the application publication number CN104698269A discloses a device and method for measuring and calculating power saving before and after transformation of a transformer. electric power.

Since the single-ended measurement method is commonly used in the power grid, the method of measuring at both ends requires the installation of a measuring device on the other side. Since the measurement errors of the measuring devices at both ends will be superimposed, the measurement accuracy is extremely high and the practicability is poor. Using the method of single-ended measurement is beneficial to simplify the measurement process and save measurement cost. However, when using the single-ended measurement method, the accuracy of the results needs to be considered. From the perspective of energy equivalence, using parameters based on average values to calculate power quantities may cause large errors when the peak-to-valley difference of the transformer is large, which is not applicable. For energy-saving renovation projects that require accurate energy-saving evaluation values as the basis for settlement.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and propose a root-mean-square-based unilateral measurement method for power saving in transformer replacement, which can be realized only by installing a measuring device on one side of the transformer.

The purpose of the present invention is achieved through the following technical solutions: a root-mean-square-based transformer replacement method for unilateral measurement of power saving, comprising the following steps:

S1. Determine the energy-saving replacement project boundary, project base period, statistical reporting period and typical work cycle T;

S2. Install voltage transformers, current transformers, and special meters that can set parameters and calculate power savings on the side of the transformer;

S3. Before the implementation of the transformer replacement project, measure the transformer current and voltage, no-load loss P ₀ , load loss P _k , rated capacity S _N , maximum load power S _IM and other parameters in the typical working cycle of the base period;

S4. After the implementation of the transformer replacement project, measure the transformer current and voltage, no-load loss P′ ₀ , load loss P′ _k , rated capacity S′ _N , maximum load power S′ _IM and other parameters during the typical working cycle of the statistical reporting period;

S5. The special meter starts the continuous calculation module, and calculates the root mean square voltage influence coefficient K _u and the root mean square current influence coefficient K _i according to the measured data;

S6. The special meter calculates the power saving according to the measured data and the calculated parameters.

The boundary conditions mentioned in step S1 refer only to the transformer body, that is, the power saved by reducing the loss of the transformer body after replacement, including no-load loss and load loss, ignoring the loss reduction corresponding to the power grid connected to it. The base period mentioned refers to the time period used to determine the energy consumption benchmark of the replacement project before the transformer replacement project is implemented. The statistical reporting period refers to the time period used to determine the electricity saved by the transformer replacement project. The typical working cycle refers to the time period that can reflect the real working condition of the transformer and calculate the operating parameters of the transformer.

The voltage transformer, current transformer and other instruments described in step S2 should meet the relevant provisions of JJG 313-2010 Verification Regulations for Current Transformers for Measurement and JJG 314-2010 Verification Regulations for Voltage Transformers for Measurement. Under the premise of reasonable cost control, the measurement accuracy should be improved as much as possible. The use conditions should meet the relevant provisions of the national standard "Current Transformer" and "Voltage Transformer". The daily maximum temperature should not exceed 40°C, the daily minimum temperature should not be lower than -25°C, and the daily average temperature should not exceed 30°C; the location of use is low altitude. At 1000m; there should be no serious pollution in the atmosphere.

The special meter mentioned in step S2 should have the calculation ability of root mean square value. At the same time, it includes the function of receiving voltage transformer and current transformer measurement data, the setting function of base period, statistical reporting period, and typical working cycle, the calculation function of saving power, and the data storage function.

In steps S3 and S4, before and after the transformer is replaced, the special electric meter calculates parameters such as no-load loss, load loss, rated capacity and maximum load power by receiving the transformer voltage and current data measured by the voltage transformer and current transformer, and store it.

The root-mean-square voltage influence coefficient K _u described in step S5 refers to the ratio of the root-mean-square value of the voltage to the rated voltage value in a typical working cycle T, which represents the degree of voltage deviation from the rated voltage in actual operation, and can be calculated according to the formula Calculated; the root mean square current influence coefficient K _i refers to the ratio of the current root mean square value to the current rated value in a typical working cycle T, which represents the degree of current deviation from the rated current in actual operation, which can be calculated according to the formula Calculated; the special meter has the function of calculating the root mean square, can calculate the above parameters according to the data measured by the transformer, and can continuously calculate the parameters according to the passage of measurement time.

The power saved by transformer replacement described in step S6 refers to the power saved by reducing the body loss before and after the transformer replacement, only considering the no-load loss P _Fe and load loss P _Cu , and other stray losses, such as lead wires, casings, fans, etc. The resulting losses are relatively small in proportion and are therefore not considered. The power saving refers to the power saving after the transformer is replaced, which refers to the difference in power loss of the transformer when the transformer load is the largest before and after the replacement. The power saving refers to the reduction in power consumption after the power saving measures are implemented compared with before the implementation under comparable circumstances.

The special meter can calculate the maximum load power S _IM , rated capacity S _N , rated no-load loss power P ₀ , and rated load loss power P _k according to the current and voltage data measured by the transformer. ₀ , P _k , S _N parameters can also be obtained on the transformer nameplate. The transformer can be replaced to save electricity according to the formula calculated.

The power saved by replacing the transformer includes two parts: the no-load power loss ΔE _Fe and the load power loss ΔE _Cu . The no-load power loss can be calculated according to the formula Calculated, the load power loss can be calculated according to the formula Calculated, the transformer replacement can save electricity according to the formula calculated.

Considering that the operating voltage of the transformer basically fluctuates around the rated voltage, it can be approximately considered that the root mean square voltage influence coefficient K _u =1, and the no-load power consumption can be simplified as ΔE _Fe =P ₀ T. In this case, the power saving of transformer replacement can be expressed as

The root-mean-square-based unilateral measurement method for transformer replacement and power saving of the present invention mainly includes: determining the project boundary, base period, statistical reporting period, and typical work cycle; installing voltage transformers, current transformers, and special meters on one side of the transformer Professional meters have advanced calculation functions for calculating root mean square value, operating parameters, and electric power; through transformer measurement, special meters can be used to calculate the no-load loss, load loss, rated capacity, and maximum compliance power of transformers before and after replacement and other operating parameters, and store them; through the collected data, the special meter continuously calculates the operating parameters such as root mean square voltage influence coefficient and root mean square current influence coefficient; according to various operating parameters, the special meter calculates the savings of transformer replacement of electric power. The method of the present invention only needs to install a measuring device on one side of the transformer, which simplifies the measurement process and saves the measurement cost; the power quantity is calculated through the influence coefficient of the root mean square voltage and current, and the measurement result is accurate, which is suitable for the need for accurate energy-saving evaluation value as the settlement basis energy-saving retrofit projects.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The present invention proposes a root-mean-square-based unilateral measurement method for transformer replacement to save power and electricity. It only needs to install a measuring device on one side of the transformer, which is applicable to the common single-ended measurement method in the power grid, which is conducive to saving costs. It simplifies the measurement process and has good economic benefits and practical value.

(2) A root-mean-square-based transformer replacement unilateral measurement method for saving power and electricity proposed by the present invention calculates the power saving through the root-mean-square voltage influence coefficient K _u and the root-mean-square current influence coefficient K _i , from energy etc. Compared with the method based on the average value, the method based on root mean square has rigorous theoretical derivation and higher measurement accuracy, and is suitable for occasions that require accurate calculation of transformer energy consumption.

Description of drawings

Fig. 1 is a flow chart of a unilateral measurement method for power saving by transformer replacement based on root mean square.

Fig. 2 is a schematic diagram of the boundary of the power transformer replacement project of the present invention.

Fig. 3 is a wiring diagram of the present invention.

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention is described in detail:

Embodiment one

(1) Overview of the embodiment;

Transformer replacement items in this embodiment are divided into high-efficiency transformer equal-capacity replacement and high-efficiency transformer capacity-increasing replacement, so as to solve the problems of high transformer loss and insufficient transformer capacity. Taking S15 and S13 transformers of the same capacity to replace S7 transformers as an example, calculate the power saved after the replacement of transformers with equal capacity. The original S7 transformer operates at a load rate of 0.5, and the load remains unchanged after the transformer is replaced. For the main technical parameters of the transformer, see Table 1.

Table 1

(2) Calculation of power saving;

The steps are shown in Figure 1. First, determine the project boundary (as shown in Figure 2). The base period, project statistical period, and typical work cycle are all taken as 720 hours. Install transformers, special meters and other equipment (as shown in Figure 3). Considering that the operating voltage is generally around the rated voltage, the root mean square voltage influence coefficient K _u is approximately taken as 1, and the calculation formula of the transformer loss is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; ,</span>$

In the formula, the rated no-load loss power P ₀ and load loss P _k can be obtained from the data on the transformer nameplate or on-site measurement. According to the load condition of the transformer, the root mean square current influence coefficient is calculated to be 0.6. Since it is equal-capacity replacement, assuming that the apparent power S _IM under the maximum load before and after replacement is 189kW, it is calculated according to the power-saving formula of unilateral measurement:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; \&prime;</span>}\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}^{<span\; class="notranslate">\; \&prime;</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span>$

After calculation, it is obtained that the S7-type transformer with a capacity of 315kVA is replaced by an S13-type transformer with the same capacity, and the power saved is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 862</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 4970</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; 189</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 315</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 340</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3650</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; 189</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 315</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.997</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; W</span>}<span\; class="notranslate">\; ,</span>$

Similarly, if the S7 transformer with a capacity of 315kVA is replaced with an S15 transformer with the same capacity, the power saved is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 862</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 4970</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; 189</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 315</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 170</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3650</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; 189</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 315</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.167</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; W</span>}<span\; class="notranslate">\; ,</span>$

(3) Calculation of power saving;

According to the power saving calculation formula:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;E</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; \&prime;</span>}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

After calculation, it is obtained that the S7-type transformer with a capacity of 315kVA is replaced by an S13-type transformer with the same capacity, and the power saved is:

$\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 862</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 4970</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 0.6</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 340</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3650</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 0.6</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 718</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; W</span>}\mathrm{<span\; class="notranslate">\; h</span>}\end{array}<span\; class="notranslate">\; ,</span>$

Similarly, if the S7 transformer with a capacity of 315kVA is replaced with an S15 transformer with the same capacity, the electricity saved is:

$\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 862</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 4970</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 0.6</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 170</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3650</span>}}{\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 0.6</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 720</span>}<span\; class="notranslate">\; )</span>\\ \mathrm{<span\; class="notranslate">\; 841</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; W</span>}\mathrm{<span\; class="notranslate">\; h</span>}\end{array}<span\; class="notranslate">\; ,</span>$

(4) Summary of power saving;

The summary of power saved in this embodiment is shown in Table 2, which is a table of power saved by replacing a 315KVA S7 transformer with an equal-capacity S13 or S15 transformer.

Table 2

Embodiment two

(1) Overview of the embodiment;

In this embodiment, the transformer replacement item is equal-capacity replacement of high-efficiency transformers, and S7-type transformers are replaced with S13-type transformers of equal capacity to solve the problem of high transformer loss. The main technical parameters of the transformer are shown in Table 1. The method based on the average current and the method based on the root mean square in the present invention are respectively used to calculate the electricity saving after replacement. The operating voltage of the transformer is near the rated voltage, and the current per unit value in a day is shown in Table 3. Table 3 is a table of the transformer current per unit value for 24 hours a day.

time/h 0 1 2 3 4 5 6 7 Current/p.u. 0.35 0.2 0.15 0.14 0.15 0.18 0.25 0.5 time/h 8 9 10 11 12 13 14 15 Current/p.u. 0.59 0.68 0.71 0.61 0.6 0.65 0.68 0.68 time/h 16 17 18 19 20 twenty one twenty two twenty three Current/p.u. 0.63 0.53 0.52 0.5 0.49 0.49 0.45 0.4

table 3

(2) Calculation of power saving;

Taking the statistical reporting period as 720 hours, according to the method based on the average current, the value of the average current is obtained as

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.46</span>}<span\; class="notranslate">\; ,</span>$

According to the calculation formula of power saving based on average current

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;E</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; ,</span>$

The calculated power saving is:

Δ(ΔE)=(0.862-0.34)×720+(4.97-3.65)×0.46 ² ×720=576.94kWh,

According to the root mean square method in the present invention, the root mean square current influence coefficient K is _obtained as

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{\sqrt{\frac{{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.50</span>}<span\; class="notranslate">\; ,</span>$

The calculated power saving is:

Δ(ΔE)=(0.862-0.34)×720+(4.97-3.65)×0.50 ² ×720=613.71kWh,

Because the root-mean-square-based transformer replacement method for saving electric power in the present invention is based on energy equivalence, it is directly deduced according to the formulas of transformer no-load power loss and load power loss, and when the measurement error of the measuring device is ignored, it can be It is considered that the calculation result is an accurate value, but the calculation result based on the average current is less than 36.77kWh. It can be seen from the above analysis that the calculation method based on the average current will have certain errors, and when the peak-to-valley difference of the transformer increases further, the error will also increase accordingly.

The above is only a preferred embodiment of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. Equivalent replacements or changes to the technical solutions and their inventive concepts all fall within the scope of protection of the invention patent.

Claims (5)

1. change the saving monolateral measuring method of quantity of electricity based on root mean square transformator for one kind, it is characterised in that include following Step:

1) energy-conservation replacing item boundaries, project base period, statistical report phase and representative calculating time are determined；

2) voltage transformer, current transformer are installed in transformator side and parameter and calculated savings quantity of electricity can be set Special table meter；

3), before the project implementation changed by transformator, transformer current voltage, open circuit loss, load in representative calculating time in base period is measured Loss, rated capacity, maximum load power parameter；

4), after the project implementation changed by transformator, transformer current voltage, unloaded damage in representative calculating time statistical report phase is measured Consumption, load loss, rated capacity, maximum load power parameter；

5) special table meter is according to measuring the data obtained, and persistently rms voltage affects coefficient, rms current affects coefficient in calculating；

6) special table meter is according to measuring the data obtained and calculating parameters obtained calculated savings quantity of electricity.

The most according to claim 1 replacing based on root mean square transformator saves the monolateral measuring method of quantity of electricity, and it is special Levy and be, in step 2, it is only necessary to install transformer and special table meter in transformator side, Measured Boundary only comprises transformator Open circuit loss and load loss.

The most according to claim 2 replacing based on root mean square transformator saves the monolateral measuring method of quantity of electricity, and it is special Levy and be, described special table meter be used for asking for root-mean-square, for receive voltage transformer, current transformer measurement data, for Base period, the statistical report phase, the setting of representative calculating time, for saving the calculating of quantity of electricity and for every result of calculation Storage.

The most according to claim 3 replacing based on root mean square transformator saves the monolateral measuring method of quantity of electricity, and it is special Levying and be, described special table meter is according to formulaIn formula, K_uFor rms voltage coefficient, u is to measure in real time Transformer voltage, T is transformator representative calculating time, U_NFor transformator rated voltage, t is the time, is calculated root-mean-square electricity Pressure affects COEFFICIENT K_u；According to formulaIn formula, K_iFor rms voltage coefficient, i is the transformator measured in real time Electric current, T is transformator representative calculating time, I_NFor transformator rated current, t is the time, is calculated rms voltage coefficient K_i；Do according to the passage of the time of measurement simultaneously and persistently calculate.

The most according to claim 4 replacing based on root mean square transformator saves the monolateral measuring method of quantity of electricity, and it is special Levying and be, described special table meter can be according to formula:

$\mathrm{\&Delta;}\left(\mathrm{\&Delta;}P\right)=(P_0+P_k\frac{S_{IM}^2}{S_N^2})-(P_0^{\&prime;}+P_k^{\&prime;}\frac{S_{IM}^{\&prime;2}}{S_N^{\&prime;2}}),$

In formula, Δ (Δ P) represents saves electric power, P₀、P_k、S_IM、S_NRefer to respectively change front transformator rated no-load loss power, volume Fixed load loss power, maximum load power, rated capacity, P '₀、P′_k、S′_IM、S′_NTransformator rated no-load after referring to respectively change Loss power, nominal load loss power, maximum load power, rated capacity, be calculated transformator and change saving electric power；Root According to formula:

$\mathrm{\&Delta;}\left(\mathrm{\&Delta;}E\right)=(P_0-P_0^{\&prime;}){K_u}^{2}T+(P_k-P_k^{\&prime;})K_i^{2}T,$

In formula, Δ (Δ E) represents saves electricity, P₀、P_kRefer to respectively change front transformator rated no-load loss power, specified complexity Loss power, K_u、K_iRefer to that rms voltage affects coefficient, rms current affects coefficient, P ' respectively₀、P′_kAfter referring to respectively change Transformator rated no-load loss power, specified complicated loss power, T refers to transformator representative calculating time, be calculated transformator Change and save electricity；Furthermore, it is contemplated that transformator working voltage fluctuates substantially near rated voltage, it is believed that rms voltage shadow Ring COEFFICIENT K_u=1, according to formula:

$\mathrm{\&Delta;}\left(\mathrm{\&Delta;}E\right)=(P_0-P_0^{\&prime;})T+(P_k-P_k^{\&prime;})K_i^{2}T,$

In formula, Δ (Δ E) represents saves electricity, P₀、P_kRefer to respectively change front transformator rated no-load loss power, specified complexity Loss power, K_iRefer to that rms current affects coefficient, P '₀、P′_kTransformator rated no-load loss power, specified after referring to respectively change Complicated loss power, T refers to transformator representative calculating time, calculate saving electricity.