A power compensation method and system based on transformer power loss, computer program product

Abstract

This invention relates to a power compensation method and system based on transformer power loss, and a computer program product, belonging to the field of power compensation technology. It determines the target power loss increment compensation coefficient of the target transformer in the power station to be compensated from a pre-constructed correspondence between transformer type and power loss increment compensation coefficient. Based on the target loss increment compensation coefficient, the output power and voltage of the high-voltage side of the target transformer, a power compensation amount for compensating the power loss of the power station is obtained. The sum of the current generating power and the power compensation amount is used as the amount of generating power to be adjusted in the power station. This invention, from a principle perspective, analyzes that the real source of power loss in the power station is the transformer, using the transformer as a breakthrough point to construct a correspondence between transformer type and power loss increment compensation coefficient, thereby realizing a power compensation method that meets the needs of various operating conditions or power stations.

Description

Technical Field

[0001] This invention relates to a power compensation method and system based on transformer power loss, as well as a computer program product, belonging to the field of power compensation technology. Background Technology

[0002] In traditional AGC / AVC (Automatic Generation Control; Automatic Voltage Control) software systems, after receiving a dispatch command, the AGC / AVC substation needs to calculate the difference between the actual power of the grid-connected branch and the target value in order to adjust the output power of the grid-connected branch to the target value. This difference is then added to the power conversion system (PCS) of the generating equipment, making the PCS's control value the current actual generating power plus this difference. However, due to power losses in the power grid, and the variations in power losses under different operating conditions, the output power of the grid-connected branch may not reach the target value after control. This necessitates a second, or even multiple, control operation by the AGC / AVC system. If the AGC / AVC system requires two or more control operations to bring the grid-connected power close to the target value, the system's response time or adjustment rate may not meet the requirements.

[0003] When issuing supplementary power values ​​to the PCS, the commonly used method in the prior art for calculating the difference correction is based on empirical calculations. This involves first issuing multiple different control target values ​​to the PCS, simultaneously detecting the actual output power of the grid-connected branch, analyzing the relationship between the PCS's generating power and the grid-connected power, and fitting this relationship into a curve with one or more slopes. Based on this curve, a control model is designed and control commands are issued. While this achieves the goal of adjusting the grid-connected power to near the target value with only one control command, it requires a high level of expertise from engineers who understand how to conduct experimental measurements and calculate the slope of the curve. Furthermore, in real-world applications, different operating conditions can arise. Even with highly skilled engineers, the slope of the fitted curve may have significant deviations, meaning that the manually calculated slope value is only applicable to certain periods and scenarios.

[0004] Chinese invention patent application CN104701859B discloses a method for reactive power distribution of generator sets in a power plant AVC system. This method includes the following steps: detecting the active power of the generator sets and obtaining the reactive power control target issued by the superior AVC master station; determining the power factor based on the active power of the generator sets and the total reactive power demand; when the power factor exceeds the basic reactive power regulation service range, distributing the reactive power of each generator based on the active power losses added to the generators and transformers when participating in paid reactive power services. The power factor is determined by... It is found that although a power-related factor is also introduced, the calculation process of the power factor in this patent (CN104701859B) does not take into account the transformer type. Since the transformer type is the main equipment that causes power loss, it is still impossible to accurately compensate for the power loss in the power station. Summary of the Invention

[0005] The purpose of this invention is to provide a power compensation method and system based on transformer power loss, as well as a computer program product, to solve the problem that the fitted relationship curve between the generated power and the grid-connected power under various operating conditions cannot obtain an accurate power compensation value. It enables the switching power of the grid-connected branch to be adjusted to near the target value with only one adjustment, and the adjustment is precise and the response speed is fast.

[0006] To achieve the above objectives, on the one hand, the present invention proposes a power compensation method based on transformer power loss, comprising the following steps:

[0007] 1) Determine the target power loss increment compensation coefficient of the target transformer in the power station to be compensated from the pre-established correspondence between transformer type and power loss increment compensation coefficient;

[0008] 2) Based on the target loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the power compensation amount used to compensate for the power loss of the power station is obtained, so that the sum of the current power generation and the power compensation amount is used as the power generation to be adjusted in the power station.

[0009] Further, the power loss increment compensation coefficient includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein, step 2) includes:

[0010] Based on the target active power loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the active power compensation amount for compensating the active power loss of the power station is obtained, and the sum of the current generating active power and the active power compensation amount is taken as the generating active power to be adjusted of the power station.

[0011] Based on the target reactive power loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, the reactive power compensation amount for compensating the reactive power loss of the power station is obtained, and the sum of the current generated reactive power and the reactive power compensation amount is taken as the reactive power to be adjusted of the power station.

[0012] Furthermore, the amount of active power to be regulated is calculated using the following formula:

[0013] ;

[0014] in, The active power to be regulated during power generation; This represents the active power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the active power loss increment compensation coefficient; This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment.

[0015] The reactive power to be regulated is calculated using the following formula:

[0016] ;

[0017] in, The reactive power to be regulated during power generation; This represents the reactive power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the reactive power loss increment compensation coefficient; This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment.

[0018] Furthermore, in the aforementioned correspondence, the transformer type includes a two-winding transformer, and the power loss increment compensation coefficient for a two-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0019] The active power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0020] ;

[0021] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0022] The reactive power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0023] ;

[0024] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's impedance voltage.

[0025] Furthermore, in the aforementioned correspondence, the transformer type includes a double-split transformer, and the power loss increment compensation coefficient for a double-split transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0026] The active power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0027] ;

[0028] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0029] The reactive power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0030] ;

[0031] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's through-impedance voltage.

[0032] Furthermore, in the aforementioned correspondence, the transformer type includes a three-winding transformer, and the power loss increment compensation coefficient for a three-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0033] The active power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0034] ;

[0035] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the equivalent load loss of the transformer; This refers to the rated capacity of the transformer.

[0036] The reactive power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0037] ;

[0038] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's equivalent impedance voltage.

[0039] The The calculation formula is: ;in, This refers to the load loss between the high and low windings of a three-winding transformer. , , These are the load losses on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0040] The The calculation formula is: Among them, V k,3-1 % represents the percentage of impedance voltage between the high and low windings of a three-winding transformer; , , These are the percentage values ​​of impedance voltage on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0041] Furthermore, it also includes: if the target transformer is a multi-transformer power station containing two or more transformer stages, then:

[0042] The sum of the active power loss increments of all transformers in a multi-transformer power station is used as the active power compensation amount to compensate for the active power loss of the power station.

[0043] The sum of the reactive power loss increments of all transformers in a multi-transformer power station is used as the reactive power compensation amount to compensate for the reactive power loss of the power station.

[0044] Furthermore, when all transformers in a multi-transformer power station are at the same voltage level, the output active power on the high-voltage side is allocated to each transformer using the following formula:

[0045] ;

[0046] in, The active power to be output at the current moment on the high-voltage side of the i-th transformer; The current active power of the high-voltage side of the i-th transformer is denoted as n; the total number of transformers in the multi-transformer power station is denoted as n; and j is the cumulative index. This represents the total active power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AGC command. This represents the actual total active power on the high-voltage side of all transformers at the current moment.

[0047] The high-voltage side output reactive power is allocated to each transformer using the following formula:

[0048] ;

[0049] in, Let be the reactive power to be output from the high-voltage side of the i-th transformer at the current moment; The current reactive power of the high-voltage side of the i-th transformer is n; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This represents the total reactive power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AVC command. This represents the actual total reactive power on the high-voltage side of all transformers at the current moment.

[0050] On the other hand, the present invention also proposes a power compensation system based on transformer power loss, including a processor, the processor being used to perform the following method steps:

[0051] 1) Determine the target power loss increment compensation coefficient of the target transformer in the power station to be compensated from the pre-established correspondence between transformer type and power loss increment compensation coefficient;

[0052] 2) Based on the target loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the power compensation amount used to compensate for the power loss of the power station is obtained, so that the sum of the current power generation and the power compensation amount is used as the power generation to be adjusted in the power station.

[0053] Further, the power loss increment compensation coefficient includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein, step 2) includes:

[0054] Based on the target active power loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the active power compensation amount for compensating the active power loss of the power station is obtained, and the sum of the current generating active power and the active power compensation amount is taken as the generating active power to be adjusted of the power station.

[0055] Based on the target reactive power loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, the reactive power compensation amount for compensating the reactive power loss of the power station is obtained, and the sum of the current generated reactive power and the reactive power compensation amount is taken as the reactive power to be adjusted of the power station.

[0056] Furthermore, the amount of active power to be regulated is calculated using the following formula:

[0057] ;

[0058] in, The active power to be regulated during power generation; This represents the active power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the active power loss increment compensation coefficient; This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment.

[0059] The reactive power to be regulated is calculated using the following formula:

[0060] ;

[0061] in, The reactive power to be regulated during power generation; This represents the reactive power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the reactive power loss increment compensation coefficient; This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment.

[0062] Furthermore, in the aforementioned correspondence, the transformer type includes a two-winding transformer, and the power loss increment compensation coefficient for a two-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0063] The active power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0064] ;

[0065] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0066] The reactive power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0067] ;

[0068] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's impedance voltage.

[0069] Furthermore, in the aforementioned correspondence, the transformer type includes a double-split transformer, and the power loss increment compensation coefficient for a double-split transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0070] The active power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0071] ;

[0072] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0073] The reactive power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0074] ;

[0075] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's through-impedance voltage.

[0076] Furthermore, in the aforementioned correspondence, the transformer type includes a three-winding transformer, and the power loss increment compensation coefficient for a three-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0077] The active power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0078] ;

[0079] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the equivalent load loss of the transformer; This refers to the rated capacity of the transformer.

[0080] The reactive power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0081] ;

[0082] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's equivalent impedance voltage.

[0083] The The calculation formula is: ;in, This refers to the load loss between the high and low windings of a three-winding transformer. , , These are the load losses on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0084] The The calculation formula is: Among them, V k,3-1% represents the percentage of impedance voltage between the high and low windings of a three-winding transformer; , , These are the percentage values ​​of impedance voltage on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0085] Furthermore, it also includes: if the target transformer is a multi-transformer power station containing two or more transformer stages, then:

[0086] The sum of the active power loss increments of all transformers in a multi-transformer power station is used as the active power compensation amount to compensate for the active power loss of the power station.

[0087] The sum of the reactive power loss increments of all transformers in a multi-transformer power station is used as the reactive power compensation amount to compensate for the reactive power loss of the power station.

[0088] Furthermore, when all transformers in a multi-transformer power station are at the same voltage level, the output active power on the high-voltage side is allocated to each transformer using the following formula:

[0089] ;

[0090] in, The active power to be output at the current moment on the high-voltage side of the i-th transformer; The current active power output of the high-voltage side of the i-th transformer is denoted as ; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This represents the total active power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AGC command. This represents the actual total active power on the high-voltage side of all transformers at the current moment.

[0091] The high-voltage side output reactive power is allocated to each transformer using the following formula:

[0092] ;

[0093] in, Let be the reactive power to be output from the high-voltage side of the i-th transformer at the current moment; The current reactive power of the high-voltage side of the i-th transformer is n; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual total reactive power on the high-voltage side of all transformers at the current moment.

[0094] On the other hand, the present invention also proposes a computer program product, including a computer program / instructions, which, when executed by a processor, implements the steps of the following method:

[0095] 1) Determine the target power loss increment compensation coefficient of the target transformer in the power station to be compensated from the pre-established correspondence between transformer type and power loss increment compensation coefficient;

[0096] 2) Based on the target loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the power compensation amount used to compensate for the power loss of the power station is obtained, so that the sum of the current power generation and the power compensation amount is used as the power generation to be adjusted in the power station.

[0097] Further, the power loss increment compensation coefficient includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein, step 2) includes:

[0098] Based on the target active power loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the active power compensation amount for compensating the active power loss of the power station is obtained, and the sum of the current generating active power and the active power compensation amount is taken as the generating active power to be adjusted of the power station.

[0099] Based on the target reactive power loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, the reactive power compensation amount for compensating the reactive power loss of the power station is obtained, and the sum of the current generated reactive power and the reactive power compensation amount is taken as the reactive power to be adjusted of the power station.

[0100] Furthermore, the amount of active power to be regulated is calculated using the following formula:

[0101] ;

[0102] in, The active power to be regulated during power generation; This represents the active power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the active power loss increment compensation coefficient; This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment.

[0103] The reactive power to be regulated is calculated using the following formula:

[0104] ;

[0105] in, The reactive power to be regulated during power generation; This represents the reactive power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the reactive power loss increment compensation coefficient; This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment.

[0106] Furthermore, in the aforementioned correspondence, the transformer type includes a two-winding transformer, and the power loss increment compensation coefficient for a two-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0107] The active power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0108] ;

[0109] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0110] The reactive power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0111] ;

[0112] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's impedance voltage.

[0113] Furthermore, in the aforementioned correspondence, the transformer type includes a double-split transformer, and the power loss increment compensation coefficient for a double-split transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0114] The active power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0115] ;

[0116] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0117] The reactive power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0118] ;

[0119] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's through-impedance voltage.

[0120] Furthermore, in the aforementioned correspondence, the transformer type includes a three-winding transformer, and the power loss increment compensation coefficient for a three-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein,

[0121] The active power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0122] ;

[0123] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the equivalent load loss of the transformer; This refers to the rated capacity of the transformer.

[0124] The reactive power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0125] ;

[0126] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's equivalent impedance voltage.

[0127] The The calculation formula is: ;in, This refers to the load loss between the high and low windings of a three-winding transformer. , , These are the load losses on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0128] The The calculation formula is: Among them, V k,3-1 % represents the percentage of impedance voltage between the high and low windings of a three-winding transformer; , , These are the percentage values ​​of impedance voltage on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0129] Furthermore, it also includes: if the target transformer is a multi-transformer power station containing two or more transformer stages, then:

[0130] The sum of the active power loss increments of all transformers in a multi-transformer power station is used as the active power compensation amount to compensate for the active power loss of the power station.

[0131] The sum of the reactive power loss increments of all transformers in a multi-transformer power station is used as the reactive power compensation amount to compensate for the reactive power loss of the power station.

[0132] Furthermore, when all transformers in a multi-transformer power station are at the same voltage level, the output active power on the high-voltage side is allocated to each transformer using the following formula:

[0133] ;

[0134] in, The active power to be output at the current moment on the high-voltage side of the i-th transformer; The current active power of the high-voltage side of the i-th transformer is denoted as n; the total number of transformers in the multi-transformer power station is denoted as n; and j is the cumulative index. This represents the total active power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AGC command. This represents the actual total active power on the high-voltage side of all transformers at the current moment.

[0135] The high-voltage side output reactive power is allocated to each transformer using the following formula:

[0136] ;

[0137] in, Let be the reactive power to be output from the high-voltage side of the i-th transformer at the current moment; The current reactive power of the high-voltage side of the i-th transformer is n; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This represents the total reactive power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AVC command. This represents the actual total reactive power on the high-voltage side of all transformers at the current moment.

[0138] The beneficial effects of this invention are as follows: The target power loss increment compensation coefficient of the target transformer in the power station to be compensated is determined from a pre-constructed correspondence between transformer type and power loss increment compensation coefficient; based on the target loss increment compensation coefficient, the output power and voltage of the high-voltage side of the target transformer, a power compensation amount for compensating the power loss of the power station is obtained, and the sum of the current generating power and the power compensation amount is used as the amount of generating power to be adjusted in the power station. This achieves the goal of analyzing the actual source of power loss in the power station as the transformer from a principle perspective, using the transformer as a breakthrough point, and constructing a correspondence between transformer type and power loss increment compensation coefficient, thereby realizing a power compensation method that meets the needs of various operating conditions or power stations. Attached Figure Description

[0139] Figure 1 This is a schematic diagram of the equivalent circuit of a two-winding transformer in a power compensation method based on transformer power loss proposed in this invention.

[0140] Figure 2 This is a schematic diagram of the equivalent circuit of a double-split transformer in a power compensation method based on transformer power loss proposed in this invention.

[0141] Figure 3 This is a schematic diagram of the equivalent circuit of a three-winding transformer in a power compensation method based on transformer power loss proposed in this invention.

[0142] Figure 4 This is a flowchart of a power compensation method based on transformer power loss proposed in this invention in a practical application scenario. Detailed Implementation

[0143] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0144] The inventive concept of this invention is to address the problem that AGC / AVC systems require multiple controls in practical applications. This invention accurately calculates the precise power loss value between the power output from the power generation equipment PCS and the output power of the grid-connected branch within the power plant. This allows the PCS to receive the actual power value that needs adjustment, enabling the AGC / AVC system to adjust the output power of the grid-connected branch to near the target value of AGC / AVC with only one control command.

[0145] Detailed implementation method 1:

[0146] The present invention proposes a power compensation method based on transformer power loss, comprising the following steps:

[0147] Step S11: Determine the target power loss increment compensation coefficient of the target transformer in the power station to be compensated from the pre-established correspondence between transformer type and power loss increment compensation coefficient. In practical applications, the power station to be compensated typically has at least one target transformer; that is, the number and type of target transformers are determined based on the actual power station setup and are not limited here. When the power station to be compensated contains two or more transformers, the target power loss increment compensation coefficient for each transformer will be obtained. Correspondingly, subsequent steps will calculate the power compensation amount for each transformer separately.

[0148] The power loss increment compensation coefficient includes the active power loss increment compensation coefficient and the reactive power loss increment compensation coefficient. In the pre-built correspondence between transformer type and power loss increment compensation coefficient, each transformer type uniquely corresponds to a set of power loss increment compensation coefficients (active power loss increment compensation coefficient and reactive power loss increment compensation coefficient).

[0149] Step S12: Based on the target loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, a power compensation amount for compensating the power loss of the power station is obtained, and the sum of the current generating power and the power compensation amount is used as the generating power to be adjusted in the power station. Here, corresponding to the active power loss increment compensation coefficient and the reactive power loss increment compensation coefficient, the power compensation amount includes active power compensation amount and reactive power compensation amount. Specifically, based on the target active power loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, an active power compensation amount for compensating the active power loss of the power station is obtained, and the sum of the current generating active power and the active power compensation amount is used as the generating active power to be adjusted in the power station. Based on the target reactive power loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, a reactive power compensation amount for compensating the reactive power loss of the power station is obtained, and the sum of the current generating reactive power and the reactive power compensation amount is used as the generating reactive power to be adjusted in the power station.

[0150] The amount of active power to be regulated is calculated using the following formula:

[0151] ;

[0152] in, The active power to be regulated during power generation; This represents the active power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the active power loss increment compensation coefficient; This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. In this invention, the active power to be adjusted is the active power compensation amount. It should be noted that the calculation formula for the active power to be adjusted can be converted to: ,in," This indicates a discrepancy between the active power to be output calculated by the AGC command and the actual active power. Therefore, in the context of… Add “(” to the base of ” ")" is to compensate for the power increase caused by instruction changes; then in " Add “ to the base” "This is to compensate for the power loss caused by the transformer equipment."

[0153] The reactive power to be regulated is calculated using the following formula:

[0154] ;

[0155] in, The reactive power to be regulated during power generation; This represents the reactive power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the reactive power loss increment compensation coefficient; This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. In this invention, the reactive power to be adjusted is the reactive power compensation amount. Similarly, it should be noted that the calculation formula for the reactive power to be adjusted can be converted to: ,in," This indicates a discrepancy between the reactive power calculated by the AvC command and the actual reactive power. Therefore, in the context of… Add “ to the base” This is to compensate for the power increase caused by instruction changes; furthermore... Add “ to the base” "This is to compensate for the power loss caused by the transformer equipment."

[0156] Through the above steps S11-S12, the switching power of the grid-connected branch can be adjusted to near the target value with only one round of adjustment. It has the characteristics of precise adjustment and fast response speed, and is suitable for power compensation and control of various power stations such as new energy power plants and energy storage power plants.

[0157] Method Detailed Implementation 2:

[0158] Following the specific embodiments described above, the pre-constructed correspondence between transformer type and power loss increment compensation coefficient in step S11 includes:

[0159] When the transformer type is a two-winding transformer, the corresponding power loss increment compensation coefficient includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient. The active power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0160] ;

[0161] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0162] The reactive power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula:

[0163] ;

[0164] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's impedance voltage.

[0165] When the transformer type is a split transformer, the corresponding power loss increment compensation coefficient includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient. The active power loss increment compensation coefficient of the split transformer is expressed by the following formula:

[0166] ;

[0167] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer.

[0168] The reactive power loss increment compensation coefficient of the double-split transformer is expressed by the following formula:

[0169] ;

[0170] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's through-impedance voltage.

[0171] When the transformer type is a three-winding transformer, the corresponding power loss increment compensation coefficient includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient. The active power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0172] ;

[0173] in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the equivalent load loss of the transformer; This refers to the rated capacity of the transformer.

[0174] The reactive power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula:

[0175] ;

[0176] in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer. This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's equivalent impedance voltage.

[0177] The The calculation formula is: ;in, This refers to the load loss between the high and low windings of a three-winding transformer. , , These are the load losses on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0178] The The calculation formula is: Among them, V k,3-1 % represents the percentage of impedance voltage between the high and low windings of a three-winding transformer; , , These are the percentage values ​​of impedance voltage on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

[0179] In practical power plants, after the power source generates active and reactive power, the power may pass through two or more transformers before being transmitted to the grid-connected branch. Therefore, when the target transformer is a multi-transformer power plant containing two or more transformers, the sum of the active power loss increments of all transformers in the multi-transformer power plant is used as the active power compensation amount to compensate for the active power loss of the power plant; the sum of the reactive power loss increments of all transformers in the multi-transformer power plant is used as the reactive power compensation amount to compensate for the reactive power loss of the power plant.

[0180] When all transformers in a multi-transformer power station are at the same voltage level, the output active power on the high-voltage side is allocated to each transformer using the following formula:

[0181] ;

[0182] in, The active power to be output at the current moment on the high-voltage side of the i-th transformer; The current active power of the high-voltage side of the i-th transformer is denoted as n; the total number of transformers in the multi-transformer power station is denoted as n; and j is the cumulative index. This represents the total active power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AGC command. This represents the actual total active power on the high-voltage side of all transformers at the current moment.

[0183] The high-voltage side output reactive power is allocated to each transformer using the following formula:

[0184] ;

[0185] in, Let be the reactive power to be output from the high-voltage side of the i-th transformer at the current moment; The current reactive power of the high-voltage side of the i-th transformer is n; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This represents the total reactive power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AVC command. This represents the actual total reactive power on the high-voltage side of all transformers at the current moment.

[0186] Method Detailed Implementation 3:

[0187] Starting from theory, we derive the relationship between PCS power generation and grid-connected power, and obtain a calculation formula for calculating the actual power loss. This formula will then guide the AGC / AVC substation in issuing precise control commands.

[0188] From a theoretical perspective, power losses in the primary wiring network of a power system are mainly generated by transmission lines and transformer equipment. In new energy power plants and energy storage power plants, there are no long-distance transmission lines; therefore, power losses are primarily borne by the transformers. (Specifically, the primary electrical wiring network of a power plant mainly consists of transformers, busbars, generating equipment, and load equipment. When the generating equipment changes its power output, the load power of the load equipment remains largely unchanged, maintaining its original power value. Therefore, the increased power output of the generating equipment is transmitted to the main grid via the transformer and busbar through the grid-connected branch. This transmission process generates certain power losses, resulting in the output power increment of the grid-connected branch not equaling the power output increment of the generating equipment. Since the power loss generated by the busbar is very small, it can be ignored, indicating that the increase in power loss is mainly generated by the transformer.) Therefore, this paper focuses on the transformer as a starting point, conducting a theoretical analysis of its power losses to derive the actual power loss value in the power plant.

[0189] Next, the calculation formulas used to calculate the increments of active and reactive power losses within the substation are explained in detail:

[0190] 1. Power loss of a two-winding transformer: For a two-winding transformer, the following is generally used... Type equivalent circuit (see) Figure 1 , wherein The equivalent circuit is a simplified model commonly used in the engineering analysis of two-winding transformers. Its core is to significantly reduce the computational complexity while ensuring a certain level of accuracy by merging impedance parameters and retaining key loss branches. It consists of an ideal transformer, a series impedance branch, and a parallel ground admittance branch.

[0191] Figure 1 In this diagram, U1 is the high-voltage side voltage of the transformer, and U2 is the low-voltage side voltage. An ideal transformer does not experience power loss; power loss is generated by both the impedance branch and the admittance branch. The impedance of the series branch of the transformer is... The admittance of the parallel branch is The formulas for calculating resistance, reactance, conductance, and susceptance are as follows:

[0192] ; (1)

[0193] in, For resistance; For reactance; Electrical conductivity; For susceptance; P k V represents the transformer's load loss (i.e., iron loss, kW). N V is the rated voltage (kV) of the transformer, when the impedance is referred to the high-voltage side of the transformer. N =V 1N When V is referred to the low-voltage side of the transformer N =V 2N S N V is the rated capacity of the transformer (kVA); k % represents the transformer's impedance voltage percentage; P0 represents the transformer's no-load loss (i.e., copper loss, kW); I0% represents the transformer's no-load current percentage.

[0194] If the transformer load loss P k The units of the transformer's no-load loss P0 are all converted to MW. The transformer's rated capacity S is converted to MW. N If the units are converted to MVA units for calculation, then formula (1) is simplified accordingly to obtain:

[0195] ; (2)

[0196] in, For resistance; For reactance; Electrical conductivity; For susceptance; P k V represents the transformer's load loss (i.e., iron loss, MW). N V is the rated voltage (kV) of the transformer, when the impedance is referred to the high-voltage side of the transformer. N =V 1N When V is referred to the low-voltage side of the transformer N =V 2N S N V is the rated capacity of the transformer (MVA); k % represents the transformer's impedance voltage percentage; P0 represents the transformer's no-load loss (i.e., copper loss, MW); I0% represents the transformer's no-load current percentage.

[0197] Given the high-voltage side voltage and output power of the transformer, calculate the power loss of the transformer. Let the high-voltage side voltage be U1, and the output power be... The power loss of the transformer series branch (impedance branch) and parallel branch (ground admittance branch) is expressed by the following formula:

[0198] ; (3)

[0199] in, This refers to the power loss in the series branch (impedance branch) of the transformer; This refers to the power loss of the transformer parallel branch (to-ground admittance branch); This represents the active power of the transformer series branch. This refers to the reactive power of the transformer series branch. This refers to the active power of the transformer parallel branch; The reactive power of transformers connected in series and parallel; The power flowing through the series branch of the transformer; For the admittance of the parallel branch.

[0200] Power flowing through the series branch of the transformer It can be expressed by the following formula (4):

[0201] ; (4)

[0202] Substituting formula (4) into formula (3), we obtain the power loss of the transformer series branch as follows:

[0203] ; (5)

[0204] Therefore, the total power loss of the transformer is:

[0205] ; (6)

[0206] Then the active power loss and reactive power loss Calculate separately, and you will get:

[0207] ; (7)

[0208] Substituting formula (2) into formula (7), we obtain the following formula (8):

[0209] ; (8)

[0210] If the high-voltage side voltage is expressed in per-unit form as And define three parameters: actual no-load active power loss Actual no-load reactive power compensation Given the load factor β, we have:

[0211] ; (9)

[0212] The load factor β varies with the power flowing through the transformer. For substations serving industrial loads, the load factor β is typically taken as 0.56. For renewable energy power plants, the load factor β needs to be calculated and determined based on the actual load conditions. For example, when the high-voltage side power changes from... Become At that time, assuming the high-voltage side voltage U1 remains constant, then:

[0213] ; (10)

[0214] For AGC, only active power is adjusted, while If the active power on the high-voltage side of the transformer becomes Then the increase in active power loss of the transformer is:

[0215] (11)

[0216] For AVC, only reactive power is adjusted, while If the reactive power on the high-voltage side of the transformer becomes... Then the increase in reactive power loss of the transformer is:

[0217] ;(12)

[0218] In the equivalent circuit diagram of a transformer, the parallel branch of the transformer to ground can be connected to either the high-voltage side or the low-voltage side of the transformer, and the calculated increase in transformer power loss will be slightly different depending on the connection.

[0219] Reuse The equivalent method divides the transformer's ground branch into two branches, each with an admittance value half of the original admittance value. The two ground branches are connected to the high-voltage side and low-voltage side of the transformer, respectively. Then, formulas (11) and (12) become:

[0220] ; (13)

[0221] When the output active power on the high-voltage side of the transformer is from Become At that time, the active power loss of the transformer itself increases. Active power generation on the low-voltage side of the transformer Compensation is required accordingly. ,Right now:

[0222] ;(14)

[0223] When the reactive power output of the high-voltage side of the transformer is from Become At that time, the reactive power loss of the transformer itself increases. Reactive power generated on the low-voltage side of the transformer Compensation is required accordingly. ,have:

[0224] ; (15)

[0225] For transformers operating for extended periods, parameters such as load loss and impedance voltage percentage will change due to variations in the external environment and equipment aging. Therefore, a load fluctuation loss coefficient K is introduced. T ,have:

[0226] ; (16)

[0227] Load fluctuation loss coefficient K T This is an empirical value, usually K. T =1.05. For new energy power plants, the load fluctuation loss coefficient K is 1.05. T It can be obtained through actual measurement.

[0228] Based on the above derivation process, the active power loss increment compensation coefficient K is defined. P And reactive power loss increment compensation coefficient K Q for:

[0229] ; (17)

[0230] Then, the active power and reactive power to be adjusted for AGC and AVC automatic control strategies are respectively:

[0231] ; (18)

[0232] Here, the coefficients involved in formulas (1) to (18) are uniform, that is, the same parameter has the same meaning, so they are not explained repeatedly.

[0233] 2. Power loss of split transformers; for double-split transformers, using... Figure 2 The diagram shows the equivalent circuit of a double-split transformer. Side 1 is the high-voltage side of the transformer, and sides 2' and 2" are the two low-voltage sides of the double-split transformer. The resistance of the series branch of the transformer is R1, the reactance of the high-voltage winding is X1, and the reactances of the two split windings on the low-voltage side are respectively... , The admittance of the parallel branch is The calculation formulas for each parameter are as follows:

[0234] ; (19)

[0235] Among them, P k V represents the transformer's load loss (i.e., iron loss, MW). N Given the transformer's rated voltage (kV), the impedance in the diagram is attributed to the low-voltage side of the transformer, resulting in V. N =V 2N V k % represents the percentage of the transformer's impedance voltage; S 1N This refers to the rated capacity (MVA) of the high-voltage side of the transformer. This refers to the through-reactance between the high-voltage winding and the total low-voltage winding; P0 is the split reactance between the two low-voltage side split windings; P0 is the transformer's no-load loss (i.e., copper loss, MW); I0% is the transformer's no-load current percentage.

[0236] According to the above formula (19), the crossing reactance between the high-voltage winding and a single low-voltage winding is called the half-cross reactance. The ratio between the split reactance and the through reactance is defined as the split coefficient, denoted by K. F This means that we get:

[0237] ; (20)

[0238] Next, Figure 2 The three reactances in the circuit are equivalent to one series reactance. ,So:

[0239] ; (twenty one)

[0240] Referring to formula (2), it can be seen that, compared with ordinary two-winding transformers, the power loss calculation formula of double-split transformers only requires the impedance voltage percentage V to be included. k % is replaced with the percentage of through-impedance voltage (V). k,1-2 Therefore, based on the two compensation coefficients for the power loss of the dual-winding transformer (i.e., the active power loss increment compensation coefficient K), P And reactive power loss increment compensation coefficient K Q The derivation and definition process of the power loss increment compensation coefficient of the double-split transformer are explained by the following formula:

[0241] ; (twenty two)

[0242] Here, the coefficients involved in formulas (19) to (22) are uniform, that is, the same parameter has the same meaning, so they are not explained repeatedly.

[0243] 3. Power loss of transformers; for three-winding transformers, using... Figure 3 The diagram shows the equivalent circuit of a three-winding transformer. Side 1 is the high-voltage side, side 2 is the medium-voltage side, and side 3 is the low-voltage side. It has three series-connected branch impedances, which are respectively... , , The parallel branch is connected to the low-voltage side, and its admittance is The calculation formulas for each parameter are as follows:

[0244] ; (twenty three)

[0245] Among them, S N P is the largest rated capacity (MVA) among the three windings of the transformer. k1 P k2 P k3 These represent the load losses (i.e., iron losses, MW) on the high-voltage side, medium-voltage side, and low-voltage side of the transformer, respectively; P0 is the no-load loss (i.e., copper losses, MW) of the transformer; V N The transformer's rated voltage (kV) is given in the diagram. The transformer's impedance is referred to the low-voltage side, resulting in V. N =V 1N V k1 %, V k2 %, V k3 % represents the percentage of impedance voltage on the high-voltage side, medium-voltage side, and low-voltage side of the transformer, respectively; I0% represents the percentage of no-load current of the transformer.

[0246] In reality, the transformer's own parameters do not provide the load loss P of a single winding on the high-voltage side, medium-voltage side, and low-voltage side. ki and impedance voltage percentage Vki The percentage represents the load loss and impedance voltage between each pair of windings. The conversion formula between them is as follows:

[0247] ; (twenty four)

[0248] Among them, P k,1-2 P k,2-3 P k,3-1 These represent the load losses (i.e., iron losses, MW) between the high-to-medium, medium-to-low, and high-to-low windings of the transformer, respectively; V k,1-2 %, V k,2-3 %, V k,3-1 The percentages represent the impedance voltage between the high-medium, medium-low, and high-low windings of the transformer, respectively; these are electrical parameters provided by the transformer itself.

[0249] There are various types of rated capacity distribution ratios for the high, medium, and low voltage windings of a step-up transformer, with two common types: 100 / 100 / 100 and 100 / 50 / 100. Formula (24) only applies to transformers with a 100 / 100 / 100 capacity ratio. For transformers with a 100 / 50 / 100 capacity ratio, the values ​​in formula (24) need to be adjusted. , , Replace with , , ;and , , The calculation formula is as follows:

[0250] ; (25)

[0251] In the AGC / AVC system of a step-up transformer, the low-voltage side is the generation side, and the high-voltage and medium-voltage sides are the consumption sides. The power and voltage on the high-voltage side are the assessment power and voltage for AGC / AVC. The reactive power distribution coefficients on the high-voltage and medium-voltage sides are respectively:

[0252] ; (26)

[0253] Similarly, the active power distribution coefficients on the high-voltage side and the medium-voltage side are respectively:

[0254] ;(27)

[0255] Find the equivalent series impedance between the low-voltage side and the high-voltage side. ,get:

[0256] ; (28)

[0257] Among them, P k13 V represents the equivalent load loss between the high-voltage and low-voltage sides of a step-up transformer. k13 % represents the percentage of equivalent reactance voltage between the high-voltage and low-voltage sides of the step-up transformer. Substituting formulas (23) and (24) into formula (28) above and simplifying, we obtain P. k13 and V k13 The formula for calculating % is:

[0258] ; (29)

[0259] Similarly, referring to formula (2), it can be seen that, compared with a regular two-winding transformer, the power loss calculation formula for a three-winding transformer only requires the load loss P to be included. k Impedance voltage percentage V k % replaced with equivalent load loss P k13 Equivalent impedance voltage percentage V k13 Therefore, based on the two compensation coefficients for the power loss of the dual-winding transformer (i.e., the active power loss increment compensation coefficient K), P And reactive power loss increment compensation coefficient K Q The derivation and definition process of the power loss increment compensation coefficient of a three-winding transformer is given by the following formula:

[0260] ; (30)

[0261] Here, the coefficients involved in formulas (23) to (30) are uniform, that is, the same parameter has the same meaning, so they are not explained repeatedly.

[0262] 4. Power loss in multi-transformer power plants: In real-world renewable energy power plants, after the power source generates active and reactive power, it may pass through two or more transformers before being transmitted to the grid-connected branches. Therefore, power losses occur in multiple transformer branches. For AGC systems, the total increase in active power loss of the power plant is the sum of the increase in active power loss of each transformer.

[0263] First, calculate the new output active power that needs to be allocated to the high-voltage side of each transformer under the new AGC active power target value. For multiple transformers of the same voltage level, the output active power on the high-voltage side of each transformer is obtained using the following formula:

[0264] ; (31)

[0265] in, The active power to be output at the current moment on the high-voltage side of the i-th transformer; The current active power of the high-voltage side of the i-th transformer is denoted as n; the total number of transformers in the multi-transformer power station is denoted as n; and j is the cumulative index. This represents the total active power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AGC command. This represents the actual total active power on the high-voltage side of all transformers at the current moment.

[0266] Then, for any transformer i, according to its and Then its active power loss increment can be calculated. Finally, the sum of the active power loss increments of all transformers is the total active power increment that the generators of the entire power station need to compensate for.

[0267] Next, for the AVC system of a new energy power plant with multiple transformers, similarly, the new output reactive power that needs to be allocated to the high-voltage side of each transformer under the new AVC reactive power target value is calculated. For multiple transformers of the same voltage level, the output reactive power corresponding to the high-voltage side of each transformer is obtained by the following formula:

[0268] ; (32)

[0269] in, Let be the reactive power to be output from the high-voltage side of the i-th transformer at the current moment; The current reactive power of the high-voltage side of the i-th transformer is n; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This represents the total reactive power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AVC command. This represents the actual total reactive power on the high-voltage side of all transformers at the current moment.

[0270] Then, for any transformer i, according to its and Then its reactive power loss increment can be calculated. Finally, the sum of the reactive power loss increments of all transformers is the total reactive power increment that the generators of the entire power station need to compensate for.

[0271] Method Detailed Implementation 4:

[0272] Based on the formula derivation process in Specific Implementation Method 3, for the AGC / AVC substation control system utilizing power plants and energy storage power stations, the following method steps can achieve the goal of adjusting the switching power of the grid-connected branch to near the target value with only one round of adjustment, without the need for secondary or multiple supplementary adjustments:

[0273] 1) Based on the actual active power, actual reactive power, target active power, and target reactive power of the current grid-connected branch, apply formula (18) from the above specific implementation method, i.e., It is used to calculate the active and reactive power output values ​​that the power generation and energy storage devices on the low-voltage bus of the transformer should control. This output power value can achieve the goal of adjusting the switching power of the grid-connected branch to near the target value with only one adjustment.

[0274] In formula (18), active power loss increment compensation coefficient K is also set for different types of transformers. P And reactive power loss increment compensation coefficient K Q .

[0275] 2) When the transformer is a two-winding transformer, the active power loss increment compensation coefficient K is obtained through formula (17) in the above specific implementation method. P And reactive power loss increment compensation coefficient K Q .

[0276] 3) When the transformer is a double-split transformer, the active power loss increment compensation coefficient K is obtained through formula (22) in the above specific implementation method. P And reactive power loss increment compensation coefficient K Q .

[0277] 4) When the transformer is a three-winding transformer, first calculate the equivalent load loss and equivalent withstand voltage percentage between the high-voltage side and the low-voltage side of the transformer using formula (29) in the above specific implementation method; then obtain the active power loss increment compensation coefficient K using formula (29) in the above specific implementation method. P And reactive power loss increment compensation coefficient K Q .

[0278] 5) When the transformer is a power station and energy storage station containing multiple transformers, according to the number of transformers, the active power output and reactive power output of each transformer are allocated respectively by formulas (31) and (32) in the above specific implementation method; then the sum of the active power loss increments of all transformers in the multi-transformer power station is used as the active power compensation amount to compensate for the active power loss of the power station; the sum of the reactive power loss increments of all transformers in the multi-transformer power station is used as the reactive power compensation amount to compensate for the reactive power loss of the power station.

[0279] Applying the above steps to the AGC / AVC substation control system of power plants and energy storage power plants, and applying it to actual projects, the switching power of the grid-connected branch can be adjusted to the target value with only one round of adjustment. The AGC / AVC control software of the energy storage power plant can adjust to the target value within 1 second, and the new energy power plant can adjust to the target value within 2 seconds, thus achieving the goal of rapid response of the AGC / AVC control software.

[0280] Method Detailed Implementation 5:

[0281] like Figure 4 The diagram shows a flowchart of a power compensation method based on transformer power loss proposed in this invention in a practical application scenario. First, the primary equipment of the power station, such as the busbar, grid-connected branch, generator, and energy storage, and their wiring relationships are read. Based on the obtained equipment and their wiring relationships, the number, type, relevant parameters, and busbars connected to each winding side of the power station are obtained.

[0282] In response to receiving a new AGC / AVC dispatch instruction, the actual active / reactive power of the grid-connected branch is obtained, and the power deviation is calculated by comparing it with the dispatch target value in the dispatch instruction. ;judge If the deviation exceeds the maximum allowable deviation of the power station, then there is no need to respond to the dispatching instructions; the current active and reactive power of the generator should be maintained, and no adjustment command should be issued.

[0283] If so, the actual output power and actual voltage of each transformer on the high-voltage side of the power station are obtained in real time; and the planned output power of the high-voltage side of each transformer is calculated (by using formula (31) or formula (32) in the above specific implementation); for each transformer, the power loss increment compensation coefficient and power loss increment are calculated based on the transformer type and related parameters; and the power loss increment of the entire station is obtained based on all transformers and their power loss increment compensation coefficient and power loss increment.

[0284] Calculate the total control output power of all power generation equipment in the power station (obtained by formula (18) in the above specific implementation, that is, the total control output power of the power generation equipment is also the amount of power to be output), decompose the total control output power into the control output power of each power generation equipment using the equal distribution algorithm, and issue corresponding power adjustment commands to each power generation equipment PCS one by one, control the power generation equipment PCS to perform power compensation until the preset execution time threshold is reached, respond to the next new AGC / AVC scheduling instruction, and continue to perform power control.

[0285] On the other hand, the present invention also proposes a power compensation system based on transformer power loss, wherein the system includes a processor for executing the steps of a power compensation method based on transformer power loss as described above.

[0286] On the other hand, the present invention also proposes a computer program product, which includes a computer program / instructions that, when executed by a processor, implement the steps of a power compensation method based on transformer power loss as described above.

[0287] The specific implementation methods of the system and the computer program product are described in detail in the specific implementation methods 1-5, and will not be repeated here.

[0288] In summary, this invention presents a power compensation method and system based on transformer power loss, along with a computer program product. It provides a formula for accurately calculating the increase in active and reactive power losses within a substation. Using this formula, the switching power of the grid-connected branch can be adjusted to near the target value with only one round of regulation, thus exhibiting precise adjustment and fast response. It is applicable to AGC and AVC control system software for various power stations, including new energy power plants and energy storage power plants.

Claims

1. A power compensation method based on transformer power loss, characterized in that, Includes the following steps: 1) Determine the target power loss increment compensation coefficient of the target transformer in the power station to be compensated from the pre-established correspondence between transformer type and power loss increment compensation coefficient; 2) Based on the target loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the power compensation amount used to compensate for the power loss of the power station is obtained, so that the sum of the current power generation and the power compensation amount is used as the power generation to be adjusted in the power station.

2. The power compensation method based on transformer power loss according to claim 1, characterized in that, The power loss increment compensation coefficient includes the active power loss increment compensation coefficient and the reactive power loss increment compensation coefficient; wherein, step 2) includes: Based on the target active power loss increment compensation coefficient, the output power and voltage of the target transformer high voltage side, the active power compensation amount for compensating the active power loss of the power station is obtained, and the sum of the current generating active power and the active power compensation amount is taken as the generating active power to be adjusted of the power station. Based on the target reactive power loss increment compensation coefficient, the output power and voltage of the target transformer high-voltage side, the reactive power compensation amount for compensating the reactive power loss of the power station is obtained, and the sum of the current generated reactive power and the reactive power compensation amount is taken as the reactive power to be adjusted of the power station.

3. The power compensation method based on transformer power loss according to claim 2, characterized in that, The amount of active power to be regulated is calculated using the following formula: ； in, The active power to be regulated during power generation; This represents the active power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the active power loss increment compensation coefficient; This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The reactive power to be regulated is calculated using the following formula: ； in, The reactive power to be regulated during power generation; This represents the reactive power generated on the low-voltage side at the current moment. This is the load fluctuation loss coefficient of the transformer; This is the reactive power loss increment compensation coefficient; This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment.

4. The power compensation method based on transformer power loss according to claim 1, characterized in that, In the aforementioned correspondence, the transformer type includes a two-winding transformer, and the power loss increment compensation coefficient for a two-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein, The active power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula: ； in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer; The reactive power loss increment compensation coefficient of the two-winding transformer is expressed by the following formula: ； in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer; This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's impedance voltage.

5. The power compensation method based on transformer power loss according to claim 1, characterized in that, In the aforementioned correspondence, the transformer type includes a double-split transformer, and the power loss increment compensation coefficient for a double-split transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein, The active power loss increment compensation coefficient of the double-split transformer is expressed by the following formula: ； in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the load loss of the transformer; This refers to the rated capacity of the transformer; The reactive power loss increment compensation coefficient of the double-split transformer is expressed by the following formula: ； in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer; This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's through-impedance voltage.

6. The power compensation method based on transformer power loss according to claim 1, characterized in that, In the aforementioned correspondence, the transformer type includes a three-winding transformer, and the power loss increment compensation coefficient for a three-winding transformer includes an active power loss increment compensation coefficient and a reactive power loss increment compensation coefficient; wherein, The active power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula: ； in, This is the active power loss increment compensation coefficient for a two-winding transformer. This refers to the active power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AGC command. This represents the actual active power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the no-load loss of the transformer; This refers to the equivalent load loss of the transformer; This refers to the rated capacity of the transformer; The reactive power loss increment compensation coefficient of the three-winding transformer is expressed by the following formula: ； in, This is the reactive power loss increment compensation coefficient for a two-winding transformer. This refers to the reactive power to be output from the high-voltage side of the transformer at the current moment, calculated according to the AVC command. This represents the actual reactive power on the high-voltage side of the transformer at the current moment. The current high-voltage side voltage in per-unit format; This refers to the rated capacity of the transformer; This represents the percentage of the transformer's no-load current. This represents the percentage of the transformer's equivalent impedance voltage. The The calculation formula is: ;in, This refers to the load loss between the high and low windings of a three-winding transformer. , , These are the load losses on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively. The The calculation formula is: Among them, V k,3-1 % represents the percentage of impedance voltage between the high and low windings of a three-winding transformer; , , These are the percentage values ​​of impedance voltage on the high-voltage side, medium-voltage side, and low-voltage side of a three-winding transformer, respectively.

7. The power compensation method based on transformer power loss according to claim 1, characterized in that, Also includes: If the target transformer is a multi-transformer power station containing two or more transformer stages, then: The sum of the active power loss increments of all transformers in a multi-transformer power station is used as the active power compensation amount to compensate for the active power loss of the power station. The sum of the reactive power loss increments of all transformers in a multi-transformer power station is used as the reactive power compensation amount to compensate for the reactive power loss of the power station.

8. The power compensation method based on transformer power loss according to claim 7, characterized in that, When all transformers in a multi-transformer power station are at the same voltage level, the output active power on the high-voltage side is allocated to each transformer using the following formula: ； in, The active power to be output at the current moment on the high-voltage side of the i-th transformer; The current active power of the high-voltage side of the i-th transformer is denoted as n; the total number of transformers in the multi-transformer power station is denoted as n; and j is the cumulative index. This represents the total active power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AGC command. This represents the actual total active power on the high-voltage side of all transformers at the current moment. The high-voltage side output reactive power is allocated to each transformer using the following formula: ； in, Let be the reactive power to be output from the high-voltage side of the i-th transformer at the current moment; The current reactive power of the high-voltage side of the i-th transformer is n; n is the total number of transformers in the multi-transformer power station; j is the cumulative index. This represents the total reactive power to be output from the high-voltage side of all transformers at the current moment, calculated according to the AVC command. This represents the actual total reactive power on the high-voltage side of all transformers at the current moment.

9. A power compensation system based on transformer power loss, characterized in that, Includes a processor for performing the method steps as described in any one of claims 1-8.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method as described in any one of claims 1-8.

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