Background
At present, two power rates, namely, a power rate and a basic power rate, are implemented for large industrial and commercial businesses in China, the basic power rate is based on the fact that the capacity or the maximum demand (namely the maximum value of the average load every 15 minutes in each month) of a transformer of an enterprise is used as the basis for calculating the power rate, the enterprise signs a contract with a power supply department, the limit is determined, and the power is collected fixedly every month without transferring the actual power consumption. Due to various reasons such as management, process, technology and the like, many large-scale enterprises have low power utilization efficiency, high power consumption cost occupying the operation cost of the enterprises, and great space saving.
For a large enterprise with centralized cooling, the load adjusting space is large, the maximum demand is used as a basic electric charge charging mode, the peak demand of the enterprise can be reduced by adjusting the load of the cooling machine, the basic electric charge expenditure of the enterprise is reduced, and therefore the electricity utilization cost of the enterprise is reduced.
According to the invention, the load of the refrigerator is dynamically and automatically adjusted according to the historical demand data and the air temperature prediction, and the temperature and humidity of the cold supply tail end are taken into consideration, so that the purposes of reducing the electricity consumption cost of customers and not influencing the comfortable experience of users are achieved.
Disclosure of Invention
The invention aims to automatically control the load of the refrigerating machine, improve the running efficiency of the refrigerating machine and effectively control the power consumption cost of an enterprise according to the condition that the power demand report value of the enterprise is an initial limit value under the premise of not influencing the comfortable experience of a user.
The invention provides a cold machine load automatic control method based on power demand prediction, which comprises the following steps:
firstly, setting a limit value D of the power demand of an enterpriselimitEnterprise cold supply end temperature limit TlimitThe rated power of n refrigerators is set as { P }chiller1,Pchiller2,...,PchillernThe percentage of the lowest current is { I } respectivelymin1,Imin2,...,Iminn};
Secondly, monitoring the real-time load P of the enterpriserealReal time demand Dreal;
Thirdly, judging the current real-time demand DrealWhether it is greater than the power demand limit DlimitIf so, the power demand limit is corrected, i.e. Dlimit=DrealAnd returning to the second step; if not, proceeding to the fourth step;
the fourth step, judge the present implementation load PrealWhether it is greater than the power demand limit DlimitIf yes, carrying out the fifth step; if not, returning to the second step;
fifthly, predicting future demand D according to historical demand data and current air temperaturepredictJudgment of DpredictWhether or not it is greater than DlimitIf yes, adjusting the load of the cold machine, and performing the sixth step; if not, returning to the second step.
Sixthly, adjusting the load of the refrigerator, wherein the method comprises the following steps:
step one, calculating a demand difference s-Dpredict-DlimitFor each cold machine I, the configured cold machine minimum current percentage IminiFor constraint, the demand difference s is distributed to each cold machine which can participate in control;
step two, the 1 st ginseng is addedIssuing a current percentage control value of the demand-controlled cooler, delaying for 1 minute, and reading a temperature value T at the cold supply tail endrealJudgment of TrealWhether or not greater than TlimitIf yes, stopping the control of the cold machine and sending an alarm signal without regulation measures; if not, continuing issuing the current percentage control values of other participating quantity control refrigerators.
Detailed Description
The invention provides a cold machine load automatic control method based on power demand prediction, which comprises the following steps:
(1) setting a contract demand declaration value signed with a power supply department as an initial limit value D of the enterprise power demandlimitEnterprise cold supply end temperature limit TlimitAnd the rated power { P of the refrigerator is configuredchiller1,Pchiller2,...,Pchillern}, percent of lowest current { Imin1,Imin2,...,Iminn};
(2) Monitoring enterprise real-time load PrealReal time demand Dreal,DrealIs a 15 minute average power statistic;
(3) judging the current DrealWhether it is greater than the power demand limit DlimitIf yes, correcting the power demand limit Dlimit=DrealAnd returning to the step (2); if not, performing the step (4);
(4) judging the current PrealWhether it is greater than the power demand limit DlimitIf yes, performing the step (5); if not, returning to the step (2);
(5) predicting future 15-minute demand D according to historical demand data and current air temperaturepredictJudgment of DpredictWhether or not it is greater than DlimitIf yes, adjusting the load of the refrigerator, and performing the step (6); if not, returning to the step (2);
(6) calculating demand difference s ═ Dpredict-DlimitFor each refrigerator i, the lowest power of the configured refrigeratorPercentage of flow IminiAnd (3) for constraint, distributing the s value of the demand difference to each cold machine which can participate in demand control, and assuming that m cold machines can participate in control, reducing the I electric current percentage of each cold machine by s/m/Pchilleri;
(7) Issuing the current percentage control value of the 1 st parameter control refrigerator and the demand control refrigerator, delaying for 1 minute, and reading the temperature value T of the cold supply tail endrealJudgment of TrealWhether or not greater than TlimitIf yes, stopping the control of the cold machine and sending an alarm signal without regulation measures; if not, the current percentage control values of other participating quantity control refrigerators are continuously issued.
In the above method for automatically controlling a cold machine load based on power demand control, the historical data refers to a historical demand value of a previous working day or a previous week, and is determined by the following method:
① if the monitoring day is Monday workday, the historical data is the demand D of the same time as the last Monday workdayhis;
② if the monitoring day is a non-Monday working day, the historical data is the demand D of the previous working day at the same timehis。
In the method for automatically controlling the load of the cold machine based on the power demand control, the predicted value D of the demand in the future 15 minutespredictThe method is determined by the following load prediction model, and the specific implementation method is as follows:
Dpredict=Dreal+W(T)+V(t)
wherein DrealW (T) is the temperature sensitive load component, and V (t) is the random load component at the moment t; w (T) ═ Ks(T-Tw),KsThe value is different for different enterprises, T is the actual temperature, TwThe critical temperature of electric heating, the Shenzhen region is 26 ℃; v (t) is calculated by using a regression calculation model (AR), and V (t) [ ]1[V(t-1)]+Φ2[V(t-2)]+...+Φp[V(t-p)]The order p and the coefficient Φ (i ═ 1,2, …, p) are determined from the history values by model identification and parameter estimation.
The following description will further describe the present invention with reference to fig. 1.
Fig. 1 reflects a specific flow of an automatic control method based on enterprise power demand prediction. Take an example where an enterprise user has 2 chillers of 360kW, a power demand declaration of 3950 kW.
(1) Setting the initial limit Dlimit of the power demand of an enterprise to 3950kW and the final temperature limit T of the cooling end of the enterpriselimitConfiguring rated power of the refrigerator {360kW, 360kW }, and lowest current percentage { 30%, 30% } at 29 ℃;
(2) monitoring enterprise real-time load Preal4002kW, real-time demand Dreal=3875kW;
(3) Current Dreal<DlimitThe power demand limit value does not need to be corrected;
(4) current Preal>DlimitAnd (5) performing the step;
(5) predicting future 15-minute demand D according to historical demand data and current temperaturepredict=4010kW>DlimitAdjusting the load of the cold machine, and performing the step (6);
(6) calculating demand difference s ═ Dpredict–DlimitWhen the temperature is 4010-;
(7) sending a current percentage control value of the 1 st cold machine: 85% -8.3% ═ 76.7%, delay time 1 minute, read cooling end temperature value Treal=26℃,Treal<TlimitAnd continuously issuing a current percentage control value of the 2 nd cooler: 80% -8.3% ═ 71.7%, delay 1 minute; reading a cooling end temperature value Treal=27℃,Treal<Tlimit. And (5) repeating the step (2) in this way, and the description is omitted.
The above examples are illustrative of the preferred embodiments of the present invention, but the present invention is not limited to the above examples, and any other modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they should be included in the scope of the present invention.