A method for distributed response of temperature-controlled loads to grid frequency regulation

Abstract

The present invention discloses a method for distributed response of temperature-controlled loads to grid frequency regulation, comprising the following steps: 1) establishing an equivalent thermal parameter model of the temperature-controlled load; 2) obtaining parameters such as indoor temperature, ambient temperature, set temperature, operating power, switch state, real-time frequency, and frequency change rate, and performing frequency regulation selection judgment to proceed to step 3) or step 4); 3) introducing a temperature offset parameter of the temperature-controlled load and establishing a model with the trigger frequency, and determining whether to participate in regulation based on a comparison between the real-time frequency and the trigger frequency; 4) using an elliptic function curve model to represent the relationship between the frequency change rate threshold and the frequency offset, and comparing it with the real-time frequency change rate, and determining whether to participate in regulation based on the trigger frequency range; 5) adjusting the switch state of the temperature-controlled load according to the control instructions obtained in steps 3) and 4) to achieve frequency regulation. The present invention enables the temperature-controlled load to assist the grid in performing primary frequency regulation, thereby improving the grid frequency quality and the economic efficiency of grid frequency regulation.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid demand-side load participation in frequency response regulation, and in particular to a method for temperature-controlled load distributed response to power grid frequency regulation. Background Art

[0002] Currently, with the development of the economy and society, resource and environmental issues are becoming increasingly prominent. The advocacy of environmental protection and the vigorous development of renewable energy are gaining popularity. However, the continuous penetration of renewable energy has brought significant uncertainty and unpredictability to the power grid, posing a significant challenge to its stable operation. In the context of smart grids, demand response has become an important means of balancing power supply and demand. Furthermore, temperature-controlled loads, as an excellent demand response resource, have attracted considerable research attention. Numerous studies have demonstrated that properly regulating temperature-controlled loads can effectively alleviate supply-demand imbalances, improve the overall operational efficiency of power systems, and achieve optimal resource allocation.

[0003] Temperature-controlled loads, such as air conditioners, refrigerators, and water heaters, are excellent demand-side response resources. They offer the following advantages: 1) excellent thermal inertia, so brief on / off control has minimal impact on normal operation; 2) fast response times, potentially reaching within seconds; and 3) low-cost, high-volume, and substantial benefits for large-scale grid regulation. However, compared to traditional generators, temperature-controlled loads are more dispersed, with significant individual variability. Furthermore, as service appliances, they must meet user comfort requirements.

[0004] Therefore, how to reasonably complete the distributed control of temperature control loads while meeting the grid frequency regulation needs and user comfort requirements is an urgent problem to be solved. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing temperature-controlled load distribution control strategy, the present invention provides a method for temperature-controlled load distributed response to grid frequency regulation, which can fully consider indoor temperature, real-time frequency and frequency change rate, participate in grid frequency regulation without affecting user comfort, reduce drastic frequency fluctuations, and effectively suppress overregulation that may exist in the temperature-controlled load distributed response frequency regulation process.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for temperature-controlled load distributed response to grid frequency regulation, comprising the following steps:

[0008] 1) Establish an equivalent thermal parameter model of the temperature control load to obtain the relationship between the indoor temperature, power and heating (cooling) capacity of the temperature control load;

[0009] 2) Obtain indoor temperature, ambient temperature, set temperature, operating power, switch status, real-time frequency and frequency change rate parameters in real time to determine whether the indoor temperature is within the allowable temperature range. Temperature-controlled loads with temperatures that are too high or too low will not participate in frequency modulation; temperature-controlled loads within the allowable temperature range will be included in frequency modulation when the frequency offset is greater than the frequency dead zone Δf db , and the frequency change rate is greater than 0, or the frequency offset is less than -Δf db If the frequency change rate is less than 0, proceed to step 3), otherwise proceed to step 4);

[0010] 3) Introduce the temperature offset parameter of the temperature control load and establish a model with the trigger frequency, respectively obtain the closing trigger frequency value when the corresponding temperature control load is in the on state, and the opening trigger frequency value when the temperature control load is in the off state. Compare the real-time frequency with the trigger frequency value to determine whether to participate in the regulation. If yes, proceed to step 5), otherwise return to step 2);

[0011] 4) Using an elliptic function curve model to represent the relationship between the frequency change rate threshold and the frequency offset, the frequency change rate threshold obtained using the elliptic function curve model based on the frequency offset is compared with the real-time frequency change rate, and combined with the temperature control load trigger frequency range, it is determined whether to participate in the regulation. If yes, proceed to step 5), otherwise return to step 2);

[0012] 5) According to the control instructions obtained in step 3) and step 4), the on / off state of the temperature control load is adjusted and the delay period T is set. delay Then determine whether to participate in the adjustment again. If yes, return to step 2), otherwise end the adjustment.

[0013] The relationship formula of the equivalent thermal parameter model of the temperature control load in step 1) is:

[0014]

[0015] Where T(k) is the indoor temperature at time k; Δt is the time step; C is the equivalent heat capacity; R is the equivalent thermal resistance; T out (k) is the ambient temperature at time k; m(k) is the on / off state of the temperature control load at time k, 1 represents on, and 0 represents off; Q is the heating / cooling capacity of the temperature control load, and its relationship with the temperature control load power is shown in formula (2):

[0016]

[0017] Where COP is the energy efficiency ratio, which represents the ratio of heating (or cooling capacity) to temperature control load power; P rate is the temperature control load power.

[0018] In heating type temperature control load, m(k) is determined according to the rule in the following formula (3). For cooling equipment, the switch state rule is opposite;

[0019]

[0020] Where T set Set the temperature for the temperature control load, δ db is the allowable temperature deviation value.

[0021] In step 2), it is determined that the indoor temperature of the temperature-controlled load is within the allowable temperature range, and the relationship is:

[0022] T min ≤T(k)≤T max (4)

[0023] Where:

[0024] T min =T set -δ db

[0025] T max =T set +δ db

[0026] In the above formula, T min and T max They are the minimum and maximum temperatures allowed by the temperature control load.

[0027] The relationship between the frequency offset and the frequency change rate in step 2) is:

[0028] Δf(k)=f(k)-f ref (5)

[0029]

[0030] Where Δf(k) is the frequency deviation value at time k, Δf'(k) is the frequency change rate at time k, f(k) is the frequency at time k, and f ref is the rated frequency.

[0031] The step 3) defines the temperature control load temperature offset parameter, and the relationship is:

[0032]

[0033] When T(k)=T min When S(k) reaches its maximum value, S(k) max =1; when T(k)=T max When S(k) reaches its minimum value, S(k) min =0.

[0034] The relationship between the temperature offset parameter of the temperature control load and the trigger frequency in step 3) is:

[0035]

[0036]

[0037] Where, To turn off the trigger frequency, is the trigger frequency, f max and f min These are the maximum and minimum values ​​of the frequency for the system to perform frequency modulation once.

[0038] In step 4), the relationship between the frequency change rate threshold and the frequency offset is expressed using an elliptic function curve model as follows:

[0039]

[0040]

[0041] In the formula

[0042] a=|Δf max min (k)|

[0043] b=|Δf′ max min (k)|

[0044] In the above formula, Δf′ on (k) and Δf′ off (k) represents the opening frequency change rate threshold and closing frequency change rate threshold calculated by the elliptic function curve, Δf max min (k), Δf′ max min (k) are the maximum (minimum) frequency deviation and the maximum (minimum) frequency change rate from the moment when the frequency is closest to the dead zone to the moment k. When the frequency Δf(k)>Δf db Then it is the maximum frequency deviation and the maximum frequency change rate. When the frequency Δf(k)<-Δf db Then it is the minimum frequency deviation and the minimum frequency change rate.

[0045] The relationship between the temperature control load trigger frequency in step 4) is:

[0046]

[0047]

[0048] In the above formula, and They represent the closing trigger frequency and opening trigger frequency after the transformation at time k, respectively. The specific expression of f' is:

[0049]

[0050] The relationship between the temperature control load trigger frequency interval in step 4) is:

[0051]

[0052]

[0053] In the above formula, and Respectively represent the maximum and minimum values ​​of the trigger frequency at time k, and They represent the maximum and minimum values ​​of the trigger frequency at time k, respectively, and ξ is the set threshold range coefficient.

[0054] The step 5) is specifically performed as follows:

[0055] According to the control instructions obtained in step 3) and step 4), the on / off state of the temperature control load is adjusted to achieve frequency regulation. After the temperature control load is adjusted, the delay T delay , and then determine whether to participate in frequency regulation. If so, return to step 2), otherwise end the regulation.

[0056] Beneficial effects: The method for distributed response of temperature-controlled loads to grid frequency regulation provided by the present invention can fully consider the temperature comfort, real-time frequency and frequency change rate of the temperature-controlled loads, realize frequency regulation under the premise of ensuring temperature comfort, and prevent overregulation at the same time, so as to realize the distributed autonomous response of large-scale temperature-controlled loads on the demand side to participate in frequency regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is the overall flow chart of the present invention.

[0058] Figure 2 It is a detailed flow chart of the temperature-controlled load distributed response to grid frequency regulation in the present invention. DETAILED DESCRIPTION

[0059] The present invention will be further described in detail below with reference to the accompanying drawings.

[0060] Figure 1 and Figure 2 The figure shows a method for temperature-controlled load distributed response to grid frequency regulation. The specific implementation process is as follows: Figure 2 The detailed steps are as follows:

[0061] Step 1: Establish an equivalent thermal parameter model of the temperature control load to obtain the relationship between the indoor temperature, power and heating (cooling) capacity of the temperature control load. The relationship of the equivalent thermal parameter model of the temperature control load is:

[0062]

[0063] Where T(k) is the indoor temperature at time k; Δt is the time step; C is the equivalent heat capacity; R is the equivalent thermal resistance; T out (k) is the ambient temperature at time k; m(k) is the on / off state of the temperature-controlled load at time k, 1 represents on and 0 represents off; Q is the equivalent heat ratio.

[0064] The relationship between the heating (cooling) capacity of the temperature control load and the temperature control load power in formula (1) is:

[0065]

[0066] Where COP is the energy efficiency ratio, which represents the ratio of heating (or cooling capacity) to temperature control load power; P rate is the temperature control load power.

[0067] In addition, local hysteresis temperature control with dead zone is integrated into the model. The switch state of the control variable m(k) is determined according to the rule in the following formula (3) in the heating type temperature control load. For the cooling equipment, the switch state rule is opposite.

[0068]

[0069] Where T set Set the temperature for the temperature control load, δ db is the allowable temperature deviation value.

[0070] Step 2: Get the indoor temperature, ambient temperature, set temperature, operating power, switch status, real-time frequency and frequency change rate parameters in real time to determine whether the indoor temperature is within the allowable temperature range. Temperature-controlled loads with temperatures that are too high or too low will not participate in frequency modulation; temperature-controlled loads within the allowable temperature range will be included in frequency modulation when the frequency offset is greater than the frequency dead zone Δf. db , and the frequency change rate is greater than 0, or the frequency offset is less than -Δf db If the frequency change rate is less than 0, then go to step 3; otherwise, go to step 4.

[0071] Among them, the indoor temperature of the temperature control load is within the allowable temperature range, and the relationship is:

[0072] T min ≤T(k)≤T max (4)

[0073] Where:

[0074] T min =T set -δ db

[0075] T max =T set +δ db

[0076] In the above formula, T min and T max They are the minimum and maximum temperatures allowed by the temperature control load.

[0077] In addition, the relationship between frequency offset and frequency change rate is:

[0078] Δf(k)=f(k)-f ref (5)

[0079]

[0080] Where Δf(k) is the frequency deviation value at time k, Δf'(k) is the frequency change rate at time k, f(k) is the frequency at time k, and f ref is the rated frequency. If Δf(k)>Δf db And Δf'(k)>0, or Δf(k)<-Δf db And Δf'(k)<0, then go to step 3, otherwise if Δf(k)>Δf db And Δf'(k)<0, or Δf<-Δf db And Δf'(k)>0, go to step 4.

[0081] Step 3: Introduce the temperature offset parameter of the temperature control load and establish a model with the trigger frequency. Obtain the closing trigger frequency value when the corresponding temperature control load is in the on state, and the opening trigger frequency value when the temperature control load is in the off state. Compare the real-time frequency with the trigger frequency value to determine whether to participate in the regulation. If yes, proceed to step 5, otherwise return to step 2.

[0082] The temperature control load temperature offset parameter S is expressed as follows:

[0083]

[0084] When T(k)=T min When S(k) reaches its maximum value, S(k) max =1; when T(k)=T max When S(k) reaches its minimum value, S(k) min =0.

[0085] In addition, the relationship between the temperature control load temperature offset parameter S and the trigger frequency is:

[0086]

[0087]

[0088] Where, To turn off the trigger frequency, is the trigger frequency, f max and f min These are the maximum and minimum values ​​of the frequency for the system to perform frequency modulation once.

[0089] According to equations (8) and (9), when the temperature control load is in the on state, Or when the temperature control load is in the off state, Then go to step 5, otherwise return to step 2.

[0090] Step 4: Use the elliptical function curve model to represent the relationship between the frequency change rate threshold and the frequency offset. Compare the frequency change rate threshold obtained using the elliptical function curve model based on the frequency offset with the real-time frequency change rate. Combined with the temperature control load trigger frequency range, determine whether to participate in regulation. If yes, proceed to step 5; otherwise, proceed to step 2.

[0091] The relationship between the frequency change rate threshold and the frequency offset is expressed by the elliptic function curve model as follows:

[0092]

[0093]

[0094] In the formula

[0095] a=|Δf max min (k)|

[0096] b=|Δf′ max min (k)|

[0097] In the above formula, Δf′ on (k) and Δf′ off (k) represents the opening frequency change rate threshold and closing frequency change rate threshold calculated by the elliptic function curve, Δf max min (k), Δf′ max min (k) are the maximum (minimum) frequency deviation and the maximum (minimum) frequency change rate from the moment when the frequency is closest to the dead zone to the moment k (when the frequency Δf(k)>Δf db Then it is the maximum frequency deviation and the maximum frequency change rate. When the frequency Δf(k)<-Δf db is the minimum frequency deviation and minimum frequency change rate).

[0098] For formula (10), when the temperature control load is in the on state, if Δf'(k)<Δf' off(k), or for formula (11), when the temperature control load is in the off state, if Δf′(k)>Δf′ on (k), then enter the temperature control load trigger frequency judgment.

[0099] In addition, the relationship between the temperature control load trigger frequency is:

[0100]

[0101]

[0102] In the above formula, and They represent the closing trigger frequency and opening trigger frequency after the transformation at time k, respectively. The specific expression of f' is:

[0103]

[0104] The trigger frequency of the temperature control load calculated according to formula (13) and formula (14) is compared with the corresponding trigger frequency interval at this time, and then the control instruction of the temperature control load is obtained.

[0105] At the same time, the relationship between the temperature control load trigger frequency interval is:

[0106]

[0107]

[0108] Where, and Respectively represent the maximum and minimum values ​​of the trigger frequency at time k, and They represent the maximum and minimum values ​​of the trigger frequency at time k, respectively, and ξ is the set threshold range coefficient.

[0109] If the temperature control load is on, turn off the trigger frequency The trigger frequency range obtained in formula (15) is If the temperature control load is in the off state, the trigger frequency is turned on. The trigger frequency range obtained in formula (16) is The temperature control load is turned on within the range. If the above conditions are met, go to step 5 to perform adjustment, otherwise return to step 2.

[0110] Step 5: According to the control instructions obtained in step 3 and step 4, the on / off state of the temperature control load is adjusted to achieve frequency regulation. After the temperature control load is adjusted, the delay period T delay T delay , and then determine whether to participate in frequency regulation. If so, return to step 2, otherwise end the regulation.

[0111] In summary, the present invention first establishes an equivalent thermal parameter model of the temperature-controlled load, and uses the obtained parameters such as indoor temperature, ambient temperature, set temperature, operating power, switch state, real-time frequency, and frequency change rate to make frequency modulation selection judgments. Then, the temperature offset parameter of the temperature-controlled load is introduced and a model with the trigger frequency is established. Whether to participate in the regulation is determined by comparing the real-time frequency with the trigger frequency. The relationship between the frequency change rate threshold and the frequency offset is represented by an elliptical function curve model, and compared with the real-time frequency change rate. Combined with the trigger frequency range, it is determined whether to participate in the regulation. Finally, the switch state of the temperature-controlled load is adjusted by the obtained control instruction to achieve the purpose of frequency modulation. In the present invention, the three aspects of temperature comfort, real-time frequency, and frequency change rate are fully considered. Without paying the cost of communication, the user's temperature comfort is fully considered to realize the distributed autonomous response of the temperature-controlled load to the grid frequency regulation. At the same time, the overmodulation phenomenon that may exist in the frequency modulation process is effectively suppressed, which can greatly improve the grid frequency quality.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for distributed temperature-controlled load response to grid frequency regulation, characterized by: The steps include: 1) Establish an equivalent thermal parameter model for the temperature control load to obtain the relationship between the indoor temperature, power, and heating (cooling) capacity of the temperature control load; 2) Get the indoor temperature, ambient temperature, set temperature, operating power, switch status, real-time frequency and frequency change rate parameters in real time to determine whether the indoor temperature is within the allowable temperature range. Temperature-controlled loads with temperatures that are too high or too low will not participate in frequency modulation; temperature-controlled loads within the allowable temperature range will be included in frequency modulation when the frequency offset is greater than the frequency dead zone. , and the frequency change rate is greater than 0, or the frequency offset is less than If the frequency change rate is less than 0, then go to step 3), otherwise go to step 4); 3) Introduce the temperature offset parameter of the temperature control load and establish a model with the trigger frequency. Obtain the closing trigger frequency value when the temperature control load is in the on state and the opening trigger frequency value when the temperature control load is in the off state. Compare the real-time frequency with the trigger frequency value to determine whether to participate in the regulation. If yes, proceed to step 5). Otherwise, return to step 2); 4) Use an elliptic function curve model to represent the relationship between the frequency change rate threshold and the frequency offset. Compare the frequency change rate threshold obtained using the elliptic function curve model based on the frequency offset with the real-time frequency change rate. Combined with the temperature control load trigger frequency range, determine whether to participate in regulation. If yes, proceed to step 5). Otherwise, return to step 2); 5) According to the control instructions obtained in step 3) and step 4), adjust the on / off state of the temperature control load and delay the delay period. Then determine whether to participate in the adjustment again, if yes, return to step 2), otherwise end the adjustment; In step 3), the relationship between the temperature control load temperature offset parameter and the trigger frequency is: （8）， （9）， Where, To turn off the trigger frequency, To turn on the trigger frequency, and The maximum and minimum values ​​of the frequency for the system to perform frequency modulation respectively; In step 4), the relationship between the frequency change rate threshold and the frequency offset is expressed using an elliptic function curve model as follows: （10）， （11）， Where, ， ， In the above formula, and They represent the opening frequency change rate threshold and closing frequency change rate threshold calculated by the elliptic function curve, respectively. 、 The frequency The time when the time most recently crossed the dead zone The maximum (minimum) frequency deviation and maximum (minimum) frequency change rate during this time. The maximum frequency deviation and the maximum frequency change rate are Then it is the minimum frequency deviation and the minimum frequency change rate.

2. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 1, characterized in that: The relationship formula of the equivalent thermal parameter model of the temperature control load in step 1) is: （1）， In the formula for Indoor temperature at all times; is the time step; is the equivalent heat capacity; is the equivalent thermal resistance; for Ambient temperature at all times; for The on / off status of the temperature control load at any moment, 1 represents on, 0 represents off; is the heating / cooling capacity of the temperature control load, and its relationship with the temperature control load power is shown in formula (2): Where COP is the energy efficiency ratio, which represents the ratio of heating (or cooling capacity) to temperature control load power; is the temperature control load power; In the case of heating type temperature control load, the state is determined according to the rule in the following formula (3). For cooling equipment, the switch state rule is opposite; （3）， In the formula Set the temperature for the temperature-controlled load, is the allowable temperature deviation value.

3. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 1, characterized in that: In step 2), it is determined that the indoor temperature of the temperature-controlled load is within the allowable temperature range, and the relationship is: （4）， Where: ， ， In the above formula, and They are the minimum and maximum temperatures allowed by the temperature control load.

4. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 1, characterized in that: The relationship between the frequency offset and the frequency change rate in step 2) is: （5）， （6）， In the formula is the frequency deviation value at time k, for The rate of change of frequency at a moment, for Time frequency, is the rated frequency.

5. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 1, characterized in that: The step 3) defines the temperature control load temperature offset parameter, and the relationship is: （7）， Among them hour Get the maximum value, ;when hour Get the minimum value, .

6. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 1, characterized in that: The relationship between the temperature control load trigger frequency in step 4) is: （12）， （13）， In the above formula, and Respectively represent The closing trigger frequency and opening trigger frequency after the moment change, The specific expression is: （14）。 7. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 6, characterized in that: The relationship between the temperature control load trigger frequency interval in step 4) is: （15）， （16）， In the above formula, and Respectively represent Always close the maximum and minimum values ​​of the trigger frequency, and Respectively represent Always open the maximum and minimum values ​​of the trigger frequency, To set the threshold range coefficient.

8. The method for temperature-controlled load distributed response to grid frequency regulation according to claim 1, characterized in that: The step 5) is specifically performed as follows: According to the control instructions obtained in step 3) and step 4), the on / off state of the temperature control load is adjusted to achieve frequency regulation. After the temperature control load is adjusted, the delay , and then determine whether to participate in frequency regulation. If so, return to step 2), otherwise end the regulation.

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