RU2249287C2 - Method for controlling group of electric heating devices - Google Patents

Abstract

FIELD: controlling temperature and time of group of electric heating devices.

SUBSTANCE: in order to take decision on turning on heating devices that heat medium to temperature below desired value real power consumption at check time intervals is compared with that desired during next closest check time interval. All user's heating devices are turned off in case comparison result is negative or equals zero. If result is positive, desired power affording coincidence of real and desired values of power consumption is found. Difference between desired and real power is found; if difference is positive, heating devices out of those disconnected are turned on in turn in order of decrease in heating temperature deviation of media from desired values whereupon difference between desired and real power is checked; if difference becomes negative, then only heating devices affording temperature deviation of heated media below that of media heated by at least one of disconnected heating devices are turned off in order of increasing temperature deviations of heated media. They are turned off until difference in power checked upon disconnection of each heating device becomes positive, and so on, or until all heating devices are turned off.

EFFECT: enhanced reliability of temperature control.

1 cl, 6 dwg

Description

The present invention relates to the electric power industry and is intended for temperature-time control of a group of electric heating devices, for example, for electric heating (cooling) and hot water supply of individual houses and apartments.

A known method of controlling regulators (see ed. St. USSR No. 395826, M. Cl. N 02 p 13/16) with different load currents, in which each regulator is turned on when the total current of other consumers and part of the regulators decrease, each of which has a larger load current than this one and is turned off at the time of increasing the same total current.

The disadvantage of this method is the low energy performance with slow changes in the load current of the power supply network, since the mode of operation of the regulators in this case has nothing to do with the operating state of the power supply network.

The closest technical solution to the proposed one is a method of controlling the temperature-time regime of electric heating devices (see RF patent No. 2189684, IPC ⁷ H 02 J 13/00, G 05 D 23/19), which optimizes the operation of the heating device taking into account both the operating condition power supply network, and the desired user cyclogram, including the desired temperature change.

The disadvantage of this method is that there is no direct relationship between the operating modes of individual heating devices during their group application.

First of all, this does not allow minimizing temperature deviations from the desired values for all control objects in case of power shortage in the power system. Some heating devices located in a heated medium with insignificant temperature deviations from the desired value may turn on, while other heating devices located in a heated medium with more significant temperature deviations from the desired value will be turned off due to a power shortage. Secondly, there are low energy indicators, since the alignment of the energy consumption schedule is not ensured.

The technical result of the invention consists in improving the quality of temperature control of heated media: reducing deviations of the temperature of the heated media from the desired values at the limit of electric power due to the redistribution of power between the heating devices in accordance with the value of the deviation of the temperature of the heated media, as well as to increase energy performance due to smoothing power graphics.

The specified technical result is achieved by a method providing for the control of a group of electric heating devices installed at the final consumer, including connecting the consumer's electric heating devices to the power supply network using a local control unit configured to control the operation of electric heating devices, in which, according to the invention, temperature-time cyclograms are used consumer representing the desired change in temperature medium, at each control time to decide on the permissibility of turning on the heating devices, the temperature of the medium being heated is lower than the desired value, compare the actual energy consumption at the controlled time intervals with the consumption desired at the next control time, expressed by a linear function through the set electric limit for the consumer power or the desired power cycle for the power supply system, all heating devices turn off If the comparison result is negative, at which the value of real energy consumption is more than desirable, or equal to zero, if it is positive, then based on the result obtained, the value of the desired power is determined, which ensures the coincidence of the values of real and desired energy consumption at the next control moment, find the difference between the desired and real power, if the difference is positive, then from among the disconnected heating devices, the heating devices in turn in order of decreasing deviations of the temperature of the heated media from the desired values, after switching on each heating device, the difference between the desired and real power is controlled, if the difference becomes negative, then only those heating devices whose temperature deviation of the heated medium are turned off in order of increasing deviations of the temperature of the heated media from the desired value less than the temperature deviation of the heated medium of any disconnected heating device, turn off until x until the power difference, controlled after turning off each heating device, becomes positive and so on, before turning on all turned off heating devices or before turning off all turned on heating devices, the temperature deviation of the heated medium is less than the temperature deviation of the medium of any disconnected heating device, turn off heating devices, the temperature of the heated medium which is higher or equal to the desired value, with the coincidence of temperature deviations tours heated media from several heating devices enable or disable heating device with a smaller sequence number.

Regulation of the energy consumption of a group of electric heating devices based on comparison of the real energy consumption at controlled intervals of time with the desired, expressed linear function through the energy limit set for the consumer or the energy cycle desired for the energy supply system, allows you to bring the actual energy consumption closer to the desired one, i.e. smooth the real schedule of energy consumption, and therefore, reduce power losses in the power supply network and ensure high energy performance.

Alternately turning on the heating devices in decreasing order of the deviation of the temperature of the heated medium from the desired value, if the difference between the desired and actual power is positive, and turning off the heating devices in increasing order of the deviation of the temperature of the heated medium from the desired value, if the difference between the desired and real power is negative, ensures alignment temperature deviations of various heated media, not allowing a sharp increase in temperature deviation in individual heated environments.

Thus, electric heaters with the largest deviation of the temperature of the heated medium from the desired value always turn on.

If necessary, in order to maintain the total energy consumption within the allotted power limit, first of all, electric heating devices are turned off with the smallest deviation of the temperature of the heated medium from the desired value.

This significantly improves the quality of temperature regulation and provides energy consumption within the established power limit.

A detailed description of the invention in one embodiment of its implementation is given below in conjunction with the accompanying drawings.

Figure 1 presents a diagram of the control structure for implementing the method of the invention.

Figure 2 shows the electric power limit diagrams (desired) _m R consumer, the real and the desired W _p W _w = P _w · t, where 0≤ t≤ T, energy on the monitored time interval T the control moments of time t _i.

Figure 3 and figure 4 show examples of cyclograms of the consumer's desired power supply system and the desired temperature of the heated medium for the consumer.

Figure 5 and figure 6 shows the algorithm of the local control unit, which is part of the control structure.

A consumer 1 connected to a power supply network 2 is shown schematically in FIG. 1. Consumer 1 has a local control unit 3 installed, which is connected through a communication line 4 to heat measuring devices 5 and a power sensor 6. Heating (adjustable) devices 7 and other (unregulated) power receivers 8 of consumer 1 are connected to the power supply network 2. 5 thermo-measuring devices are located in those environments 9 (rooms, water heaters), the temperature of which is affected.

A method of controlling a group of electric heating devices is as follows.

On a controlled time interval T equal to 30 minutes, at control times t _i , where i = 1, 2, ..., N (Fig. 2), the local control unit 3 through the communication line 4 interrogates all the heat measuring devices 5. The interval between the control time points, depending on the required accuracy of determining the energy consumption and the temperature of the heated medium, is usually about one or several minutes, which is incomparably longer than the time required for all operations to be performed by the local (microprocessor) control unit 3 and the power computation power sensor 6. In the database of the local control unit 3 stores data desired for the system power cyclogram power P (t) (3) or an electric power limit value P _m, as well as desirable to the consumer temperature-time sequence diagrams θ _w (t) (FIG. 4) for each heated medium 9.

If the temperature of the heated medium 9 is higher or equal to the desired value, then a shutdown command is received from the local control unit 3 through the communication line 4 to the corresponding heating device 7.

If the temperature of the heated medium 9 is lower than the desired value, then in order to make a decision on whether the heating device 7 can be turned on at the sub-interval [t _i , t _{i + 1} ] in the local control unit 3, an energy analysis is carried out in accordance with the work program. The desired energy consumption Δ W is _calculated on the subinterval [t _i , t _{i + 1} ]

Δ W _Жi = (W _{Ж (i + 1)} -W _pi ),

where W W _{(i + 1)} = R _m · t _{i + 1} is the desired energy consumption in the subinterval [t ₀ , t _{i + 1} ], W _pi is the real energy consumption in the subinterval [t ₀ , t _i ], is calculated based on the data polling the power sensor 6.

If Δ W _Жi ≤ 0, i.e. on the controlled interval T, the real power consumption at the control time t _i exceeds or equal to the desired power consumption at the next control time t _{i + 1} , then the shutdown command is sent from the local control unit 3 to the heating devices 7.

If Δ W _Жi > 0, then the local control unit 3 determines the desired power at the subinterval [t _i , t _{i + 1} ] according to the expression

P _Жi = Δ W _Жi / (t _{i + 1} -t _i ).

The desired power is such a constant power in the subinterval [t _i , t _{i + 1} ], the power of which during this subinterval (shown in dashed lines in Fig. 2) ensures coincidence in the controlled interval T by the next control moment t _{i + 1} real power consumption with desirable. The local control unit 3 reads from the output of the power sensor 6 the value of the real power P _pi and compares it with the value of the desired power P _i .

If the result of the power comparison is greater than zero, i.e. _Zhi P> P _pi, at the output of the local control unit 3 generates a command to switch the heating device 7 with the greatest number of heating devices 7 disconnected temperature deviation of the heated medium 9 from the desired value. After the inclusion of the heating device 7 with the real power value of the power sensor 6 is read again and P _pi is compared with the desired R _zhi, etc., until local control unit 3 does not include all disconnected heating device 7 capacity or until the result of comparison audio becomes negative. If the local control unit 3 turns on all the heating devices 7, then it goes into standby mode for the mark of the next control point in time t _{i + 1} .

If the result of the power comparison becomes negative or equal to zero, i.e. the electric power consumed during the monitoring is equal to or greater than the desired value, then the local control unit 3 generates a command to turn off the heating device 7 with a minimum deviation of the temperature of the heated medium 9 from the desired value. After turning off this heating device 7, the local control unit 3 again reads the value of the real power _Рi and, if it is greater than the desired power _Рi , it generates a command to turn off the next heating device 7 with a minimum deviation of the temperature of the heated medium 9 from the desired value, etc. . If the real power _Pi becomes less than the desired _Pi , then the local control unit 3 includes a heating device 7 with the maximum deviation of the temperature of the heated medium from the desired value. When all turned-on heating devices 7 are turned off or all turned-off heating devices are turned on, the local control unit 3 goes into standby mode for the label of the next control time instant t _{i + 1} and the cycle repeats.

Thus, in the formation of the energy consumption schedule at the power limit, heating devices with the greatest deviation of the temperature of the heated medium from the desired value are primarily involved. This distribution of electricity between the heating devices provides a decrease in the amplitude of deviations of the temperature of the heated medium from the desired value, improves the quality of regulation.

When using this method during cooling, the devices are switched off at a temperature of the medium to be cooled below the desired value.

Claims (1)

A method of controlling a group of electric heating devices installed at an end consumer, comprising connecting a consumer's electric heating devices to a power supply network using a local control unit configured to control the operation of electric heating devices, which consists in using temperature-time consumer cyclograms representing the desired change in the temperature of the heated environment, characterized in that at each control time They interrogate all thermo-measuring devices and, in order to decide on the permissibility of turning on heating devices, the temperature of the medium being heated below the desired value, compare the actual energy consumption at the controlled time intervals with the consumption desired at the next nearest monitoring time, expressed by a linear function through the electric power limit set for the consumer or the desired power cycle for the power supply system, all heating devices are turned off consumer, if the comparison result is negative, in which the value of real energy consumption is more than desirable, or equal to zero, if - positive, then on the basis of the result obtained, the value of the desired power is determined, which ensures the coincidence of the values of real and desired energy consumption at the next closest control moment, find the difference between the desired and real power, if the difference is positive, then from the number of disconnected heating devices include alternately heating Real devices in the decreasing order of deviations of the temperature of the heated media from the desired values, after switching on each heating device, the difference between the desired and real powers is controlled, if the difference becomes negative or equal to zero, then only those heating devices are turned off in the order of increasing deviations of the temperature of the heated media from the desired value the deviation of the temperature of the heated medium which is less than the deviation of the temperature of the heated medium in at least one and disconnected heating devices, they are turned off until the power difference controlled after turning off each heating device becomes positive, and so on until all heating devices are turned off or all heating devices are turned off, the deviation of the temperature of the heated medium which is less than the deviation of the temperature of the medium at least one of the disconnected heating devices, turn off the heating device, the temperature of the heated medium which greater than or equal to a desired value, the coincidence of the temperature deviation the heating medium at several heating devices enable or disable heating device with a smaller sequence number.

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