Capacity design method and device for low-voltage alternating-current system of power plant

Abstract

The invention provides a capacity design method and device for a power plant low-voltage alternating current system, and belongs to the technical field of power systems. The method comprises the following steps: respectively determining respective demand loads of LC and MCC based on demand coefficients, full load currents and rated voltages of first equipment under a load center LC in a power plant and second equipment under a motor control center MCC; and determining the design capacity of the LC according to the respective demand load of the LC and the MCC and the corresponding design allowance. According to the invention, through a full load current calculation method, the demand coefficient is introduced to respectively calculate the demand loads of the first device and the motor control center MCC under the LC, and the design margins of the MCC and the LC are fully considered, so that the design capacity of the load center LC is determined, and the selection of a transformer in a low-voltage AC system of a power plant is facilitated. The constant volume method based on the full-load current is not limited by equipment types and is closer to actual requirements in a power plant working scene, the accuracy of transformer type selection is improved, and the safety and economical efficiency of a power plant are guaranteed.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power systems, and in particular to a capacity design method and device for a low-voltage AC system in a power plant. Background Art

[0002] In the relevant technology, the load calculation for plant electricity mainly includes the conversion coefficient method and the shaft power method. Among them, the conversion coefficient method usually takes different conversion coefficients for each load according to different unit capacities. The total calculated load of the power plant is determined by the sum of the conversion coefficients of each load in the power plant and the calculated power of the equipment, and the equipment model of the power plant transformer is selected. This method is relatively simple and widely used. It is often used for load calculation in power plants and substations. The shaft power method is a method of dividing the maximum operating shaft power of the motor by the corresponding motor efficiency and power factor, and then multiplying it by the simultaneity rate to obtain the calculated load.

[0003] However, in practical applications, the conversion factor method has certain limitations because it is based on the empirical value of the unit capacity, and the conversion factor method does not necessarily reflect the actual demand. The shaft power method is limited to the calculated capacity of motor equipment and is not applicable to non-motor equipment, which has certain limitations. Summary of the invention

[0004] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the first embodiment of the present disclosure proposes a capacity design method for a low-voltage AC system of a power plant, wherein the low-voltage AC system includes a load center LC, a motor control center MCC, a first device, and a second device. The load center LC supplies power to the motor control center MCC and the first device, and the motor control center MCC supplies power to the second device. The method includes the following steps:

[0006] Determine the required load of the motor control center MCC according to the demand factor, full load current and rated voltage corresponding to the second device; wherein the demand factor is used to represent the ratio of the load demand of the device to the full load;

[0007] Determining a design load of the motor control center MCC according to a required load of the motor control center MCC and a first design margin;

[0008] determining a calculated load of the first device according to a demand factor, a full load current, and a rated voltage corresponding to the first device;

[0009] Determining a calculated total load of the load center LC based on the design load of the motor control center MCC and the calculated load of the first device;

[0010] The design capacity of the load center LC is determined according to the calculated total load of the load center LC and the second design margin.

[0011] In some embodiments of the present disclosure, the required load of the motor control center MCC includes required active power, required reactive power and required capacity; according to the demand coefficient, full load current and rated voltage corresponding to the second device, the required load of the motor control center MCC is determined by the following formula:

[0012]

[0013] DL_kW=DL_kVA×pf2

[0014]

[0015] Total_DL_kW=∑DL_kW

[0016] Total_DL_kVAR=∑DL_kVAR

[0017]

[0018] Among them, DL_kVA represents the required capacity of the second device, DL_kW represents the required active power of the second device, DL_kVAR represents the required reactive power of the second device, Total_DL_kW represents the required active power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, DF2 is the demand coefficient corresponding to the second device, ph is the number of power phases of the second device, FLA2 is the full load current corresponding to the second device, Voltage2 is the rated voltage corresponding to the second device, and pf2 is the power factor of the second device.

[0019] In some embodiments of the present disclosure, according to the required load of the motor control center MCC and the first design margin, the design load of the motor control center MCC is determined by the following formula, including:

[0020] Design_kVA2=(1+DM1)×Total_DL_kVA

[0021] Design_kW2=(1+DM1)×Total_DL_kW

[0022] Design_kVAR2=(1+DM1)×Total_DL_kVAR

[0023] Among them, Design_kVA2 represents the design capacity of the motor control center MCC, Design_kW2 represents the design active power of the motor control center MCC, Design_kVAR2 represents the design reactive power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, and DM1 is the first design margin.

[0024] In some embodiments of the present disclosure, the calculated load of the first device includes calculated capacity, calculated active power, and calculated reactive power; the calculated load of the first device is determined by the following formula according to the demand factor, full load current, and rated voltage corresponding to the first device:

[0025]

[0026] Design_kW1=Design_kVA1×pf1

[0027]

[0028] Among them, Design_kVA1 represents the calculated capacity of the first device, Design_kW1 represents the calculated active power of the first device, Design_kVAR1 represents the calculated reactive power of the first device, DF1 is the demand factor corresponding to the first device, FLA1 is the full load current corresponding to the first device, Voltage1 is the rated voltage corresponding to the first device, and pf1 is the power factor of the first device.

[0029] In some embodiments of the present disclosure, determining the calculated total load of the load center LC based on the design load of the motor control center MCC and the calculated load of the first device includes: determining the product of the design load of the motor control center MCC and the load diversity coefficient LDF2 of the motor control center MCC as the first calculated load of the motor control center MCC; determining the product of the calculated load of the first device and the load diversity coefficient LDF1 of the first device as the first calculated load of the first device; adding the first calculated load of the motor control center MCC and the first calculated load of the first device to obtain the calculated total load of the load center LC; wherein, the load diversity coefficient LDF2 of the motor control center MCC = 1-DM1, and the load diversity coefficient LDF1 of the first device = 1.

[0030] In some embodiments of the present disclosure, determining the calculated total load of the load center LC based on the design load of the motor control center MCC and the calculated load of the first device includes: taking the sum of the design load of the motor control center MCC and the calculated load of the first device as the calculated total load of the load center LC.

[0031] In some embodiments of the present disclosure, the calculated total load of the load center LC includes the calculated active power, calculated reactive power and calculated capacity of the total load of the load center LC; according to the calculated total load of the load center LC and the second design margin, the design capacity of the load center LC is determined by the following formula:

[0032] TDL_kW with DM=(1+DM2)×Total DivL_kW

[0033] TDL_kVAR with DM=(1+DM2)×Total DivL_kVAR

[0034]

[0035] Among them, Total DivL_kW represents the calculated active power of the total load of the load center LC, Total DivL_kVAR represents the calculated reactive power of the total load of the load center LC, DM2 is the second design margin, TDL_kW with DM is the design active power of the total load of the load center LC, TDL_kVAR with DM is the design reactive power of the total load of the load center LC, and LCXFMR_Design_kVA with DM is the design capacity of the load center LC.

[0036] The second aspect of the present disclosure provides a capacity design device for a low-voltage AC system of a power plant, wherein the low-voltage AC system includes a load center LC, a motor control center MCC, a first device, and a second device. The load center LC supplies power to the motor control center MCC and the first device, and the motor control center MCC supplies power to the second device. The device includes:

[0037] A first determination module is used to determine the required load of the motor control center MCC according to the demand coefficient, full load current and rated voltage corresponding to the second device; wherein the demand coefficient is used to represent the ratio of the load demand of the device to the full load;

[0038] A second determination module is used to determine the design load of the motor control center MCC according to the required load of the motor control center MCC and the first design margin;

[0039] A third determination module is used to determine the calculated load of the first device according to the demand factor, full load current and rated voltage corresponding to the first device;

[0040] a fourth determination module, configured to determine a calculated total load of the load center LC according to a design load of the motor control center MCC and a calculated load of the first device;

[0041] The fifth determination module is used to determine the design capacity of the load center LC according to the calculated total load of the load center LC and the second design margin.

[0042] A third aspect of the present application provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor;

[0043] The memory stores computer-executable instructions;

[0044] The processor executes the computer-executable instructions stored in the memory to implement the method described in the first aspect.

[0045] The fourth aspect of the present application provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer execution instructions, and the computer execution instructions are used to implement the method described in the first aspect when executed by a processor.

[0046] The capacity design method of the low-voltage AC system of the power plant provided by the present disclosure, through the full-load current calculation method, introduces the demand coefficient to determine the demand load of the first equipment and the motor control center MCC under the load center LC in the power plant, and fully considers the design margins of the motor control center MCC and the load center LC, thereby determining the design capacity of the load center LC, so as to facilitate the selection of transformers in the low-voltage AC system of the plant. The capacity determination method based on full-load current disclosed in the present disclosure is not limited by the type of equipment, and is closer to the actual needs in the working scene of the power plant, improves the accuracy of transformer selection, ensures the safety of the power plant, and ensures the economy of transformer selection.

[0047] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and / or additional aspects and advantages of the present disclosure will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0049] Figure 1 A flow chart of a capacity design method for a low-voltage AC system of a power plant provided by an embodiment of the present disclosure;

[0050] Figure 2 A schematic diagram of a low-voltage AC system of a power plant provided by an embodiment of the present disclosure;

[0051] Figure 3 A schematic diagram of a capacity design device for a low-voltage AC system in a power plant provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0052] Embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0053] Specifically, the capacity design method and device of the low-voltage AC system of a power plant according to an embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0054] It should be noted that the formula for the conversion coefficient method used for load calculation in the relevant technology can be referred to as follows:

[0055] S c =∑KP

[0056] Where:

[0057] S c Calculate load (kVA);

[0058] K conversion factor, the value can be obtained according to Table 1;

[0059] P is the calculated power of the load (kW);

[0060] Table 1 Conversion coefficient table

[0061]

[0062] The calculated power P of the motor can be determined according to the operating status of the load:

[0063] a) For motors that run continuously (including often continuously and not often continuously), P = P e

[0064] Where: P e —Rated power of the motor (kW).

[0065] b) For short-term and intermittent operation of the motor: P = 0.5P e

[0066] The calculation formula of the shaft power method can be referred to as follows:

[0067]

[0068] Where:

[0069] K t The simultaneous rate is 0.9 for new power plants and 0.95 for expanded power plants;

[0070] P z Maximum operating shaft power (kW), for machine / furnace auxiliary equipment, generally corresponds to BMCR operating conditions;

[0071] η corresponds to the motor efficiency in terms of shaft power;

[0072] The motor power factor corresponding to the shaft power;

[0073] In view of the calculation limitations of the conversion coefficient method and the shaft power method, the present disclosure proposes a capacity design method and device for a low-voltage AC system of a power plant, which is not limited by the type of equipment and can more accurately determine the design capacity and is closer to the actual needs in the working scenario of the power plant.

[0074] Figure 1 A flow chart of a capacity design method for a low-voltage AC system of a power plant provided in an embodiment of the present disclosure is provided. Figure 2 A schematic diagram of a low-voltage AC system of a power plant provided in an embodiment of the present disclosure.

[0075] like Figure 2 As shown, the low voltage AC system includes a load center LC, a motor control center MCC, a first device and a second device. Figure 2 The main equipment of the load center (including LCA section and LCB section) includes the load center transformer, busbar in the switch cabinet, incoming line circuit breaker and feeder circuit breaker. The feeder circuit of the load center mainly supplies power to the motor control center (MCC) and motors with power ranging from 90 to 200kW. The motor control center MCC (such as Figure 2 As shown, the load center LC includes MCCA section and MCCB section) and is assembled by one or more closed switch cabinets installed on the ground, and the switch cabinet contains a horizontal main bus and many motor control units. The load center LC supplies power to the motor control center MCC and the first equipment, and the first equipment includes the first motor equipment and the first non-motor equipment. The motor control center MCC supplies power to the second equipment (the second equipment powered by the motor control center MCC section is not shown in the figure), and the second equipment includes the second motor equipment and the second non-motor equipment.

[0076] like Figure 1 As shown, the capacity design method of the low-voltage AC system of a power plant provided by the embodiment of the present disclosure may include the following steps:

[0077] Step 101, determining the required load of the motor control center MCC according to the demand coefficient, full load current and rated voltage corresponding to the second device, wherein the demand coefficient is used to indicate the ratio of the load demand of the device to the full load.

[0078] It should be noted that since some loads in the power system will not operate at full power and / or intermittently operate at full power, the actual power demand of the system must be less than the sum of the power of all loads in the system. Therefore, when analyzing and calculating the system load, it is necessary to introduce an appropriate demand factor to better reflect the actual operation situation.

[0079] Due to the rapid development of the power system, the rapid development of thermal power, new energy, nuclear power, etc., the conversion coefficients in the conversion coefficient method are insufficiently covered, and some process equipment cannot find suitable conversion coefficients, and can only take similar process equipment conversion coefficients, resulting in calculation deviations. To this end, the present disclosure provides a value table for the load demand coefficient in the power system, as shown in Table 2, which can more comprehensively and accurately determine the demand coefficient of the equipment in the power plant. In the embodiment of the present disclosure, the demand coefficient corresponding to the second equipment and the demand coefficient corresponding to the first equipment can both refer to Table 2 for value.

[0080] Table 2 Load demand coefficient

[0081]

[0082]

[0083] The required load of the motor control center MCC includes required active power, required reactive power and required capacity. In some embodiments of the present disclosure, the required active power, required reactive power and required capacity of each second device can be determined according to the demand coefficient, full load current and rated voltage corresponding to the second device, and then added together to obtain the total required load of the motor control center MCC. Specifically, the required load of the motor control center MCC can be determined by the following formula:

[0084]

[0085] DL_kW=DL_kVA×pf2

[0086]

[0087] Total_DL_kW=∑DL_kW

[0088] Total_DL_kVAR=∑DL_kVAR

[0089]

[0090] Among them, DL_kVA represents the required capacity of the second device, DL_kW represents the required active power of the second device, DL_kVAR represents the required reactive power of the second device, Total_DL_kW represents the required active power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, DF2 is the demand coefficient corresponding to the second device, ph is the number of power phases of the second device, FLA2 is the full load current corresponding to the second device, Voltage2 is the rated voltage corresponding to the second device, and pf2 is the power factor of the second device. The full load current FLA2 corresponding to the second device and the full load current FLA1 corresponding to the first device can be calculated through the power factor and motor efficiency of the equipment, and the ordered equipment parameters can be used for detailed engineering calculations.

[0091] Step 102: determining the design load of the motor control center MCC according to the required load of the motor control center MCC and the first design margin.

[0092] When determining the design load of the motor control center MCC, in addition to considering the total demand load of the second equipment, it is also necessary to consider the load changes that may occur during the design process and the subsequent expansion requirements of the power plant (depending on the design parameters or design standards of the project). Therefore, the design load of the motor control center MCC is determined based on the demand load of the motor control center MCC and the first design margin. Specifically, the design load of the motor control center MCC can be determined by referring to the following formula:

[0093] Design_kVA2=(1+DM1)×Total_DL_kVA

[0094] Design_kW2=(1+DM1)×Total_DL_kW

[0095] Design_kVAR2=(1+DM1)×Total_DL_kVAR

[0096] Among them, Design_kVA2 represents the design capacity of the motor control center MCC, Design_kW2 represents the design active power of the motor control center MCC, Design_kVAR2 represents the design reactive power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, and DM1 is the first design margin.

[0097] As a possible implementation, unless otherwise specified in the contract, the minimum value of the first design margin DM1 may be set to 20%.

[0098] In addition, the first design margin DM1 can also be used to determine the total load current of the motor control center MCC design load, so as to select the MCC incoming cable. Optionally, the total load current of the MCC design load can be taken as the sum of the full load current considering the first design margin DM1 and 25% of the full current of the largest motor by referring to the following formula:

[0099] Design_FLA=(1+DM1)*Total FLA+25%FLA of Largest Motor

[0100] Among them, Design_FLA is the total load current (A) of the MCC design load, DM1 is the first design margin, TotalFLA is the sum of the full load currents of the second equipment, and FLA of Largest Motor is the full load current of the largest motor in the second equipment.

[0101] Step 103, determining the calculated load of the first device according to the demand factor, full load current and rated voltage corresponding to the first device.

[0102] The calculated load of the first device includes calculated capacity, calculated active power and calculated reactive power. In some embodiments of the present disclosure, the calculated load (or demand load) of the first device can be determined by the following formula according to the demand factor, full load current and rated voltage corresponding to the first device:

[0103]

[0104] Design_kW1=Design_kVA1×pf1

[0105]

[0106] Among them, Design_kVA1 represents the calculated capacity of the first device, Design_kW1 represents the calculated active power of the first device, Design_kVAR1 represents the calculated reactive power of the first device, DF1 is the demand factor corresponding to the first device, FLA1 is the full load current corresponding to the first device, Voltage1 is the rated voltage corresponding to the first device, and pf1 is the power factor of the first device. The demand factor DF1 corresponding to the first device can be obtained by referring to Table 2.

[0107] Step 104 , determining the calculated total load of the load center LC according to the design load of the motor control center MCC and the calculated load of the first device.

[0108] The design load of the motor control center MCC and the calculated load of the first device under the load center LC are calculated respectively through steps 101 to 103. In some embodiments of the present disclosure, the sum of the design load of the motor control center MCC and the calculated load of the first device can be used as the calculated total load of the load center LC (including the calculated active power, calculated reactive power and calculated capacity of the total load of the load center LC).

[0109] Step 105 , determining the design capacity of the load center LC according to the calculated total load of the load center LC and the second design margin.

[0110] The calculated total load of the load center LC includes the calculated active power, calculated reactive power and calculated capacity of the total load of the load center LC. When determining the design capacity of the load center LC, it is necessary to consider the load changes that may occur during the design process and the design margin required by the contract for the subsequent expansion of the power plant (depending on the design parameters or design standards of the project). In some embodiments of the present disclosure, the design capacity of the load center LC can be determined according to the calculated total load of the load center LC and the second design margin by the following formula:

[0111] TDL_kW with DM=(1+DM2)×Total DivL_kW

[0112] TDL_kVAR with DM=(1+DM2)×Total DivL_kVAR

[0113]

[0114] Among them, Total DivL_kW represents the calculated active power of the total load of the load center LC, Total DivL_kVAR represents the calculated reactive power of the total load of the load center LC, DM2 is the second design margin, TDL_kW with DM is the designed active power of the total load of the load center LC, TDL_kVAR with DM is the designed reactive power of the total load of the load center LC, and LCXFMR_Design_kVAwith DM is the designed capacity of the load center LC. When selecting a low-voltage dry-type transformer for the plant low-voltage AC system (such as Figure 2 Transformer A and transformer B) shown in the figure are selected based on the design capacity of the load center LC and the principle that the rated capacity of the LCT (transformer) needs to be greater than or equal to the design capacity of the LC.

[0115] Optionally, unless otherwise specified in the contract, the minimum value of the second design margin DM2 may be set to 10%.

[0116] Since, in the process of determining the design capacity of the load center LC, the first design margin DM1 is considered to expand the design load of the motor control center MCC, and the second design margin DM2 is also considered to expand the design load of the load center LC, load redundancy may be caused in actual application, resulting in the determined design capacity of the load center LC far exceeding the actual required capacity. For this reason, a load diversity coefficient is introduced in some embodiments of the present disclosure to reflect load redundancy. Optionally, the load diversity coefficient can take the following values: the load diversity coefficient LDF2 of the motor control center MCC = 1-DM1, and the load diversity coefficient LDF1 of the first device = 1.

[0117] In one possible implementation, the product of the design load (design capacity, design active power, design reactive power) of the motor control center MCC and the load diversity coefficient LDF2 of the motor control center MCC can be determined as the first calculated load of the motor control center MCC. The product of the calculated load of the first device and the load diversity coefficient LDF1 of the first device can be determined as the first calculated load of the first device, which can be determined by referring to the following formula:

[0118] DivL_kVA1=LDF1×Design_kVA1

[0119] DivL_kW1=LDF1×Design_kW1

[0120] DivL_kVAR1=LDF1×Design_kVAR1

[0121] Among them, DivL_kVA1 is the first calculated capacity of the first device, DivL_kW1 is the first calculated active power of the first device, DivL_kVAR1 is the first calculated reactive power of the first device, LDF1 is the load diversity coefficient of the first device, Design_kVA1 represents the calculated capacity of the first device, Design_kW1 represents the calculated active power of the first device, and Design_kVAR1 represents the calculated reactive power of the first device.

[0122] The first calculated load of the motor control center MCC and the first calculated load of the first device are added to obtain the calculated total load of the load center LC (including the calculated active power Total DivL_kW of the total load of the load center LC and the calculated reactive power Total DivL_kVAR of the total load of the load center LC). Then, the design capacity of the load center LC is determined by the calculated active power Total DivL_kW of the total load of the load center LC, the calculated reactive power Total DivL_kVAR of the total load of the load center LC and the second design margin DM2 (refer to the relevant formula for determining the design capacity of the load center LC according to the calculated total load of the load center LC and the second design margin in step 105), thereby avoiding load redundancy and improving the accuracy of the design capacity of the load center LC.

[0123] In some embodiments, steps 101 - 102 and step 103 may be performed in an interchanged order or simultaneously.

[0124] By implementing the embodiments of the present disclosure, the full-load current calculation method is used to introduce the demand coefficient to determine the demand load of the first equipment and the motor control center MCC under the load center LC in the power plant, and the design margins of the motor control center MCC and the load center LC are fully considered, so as to determine the design capacity of the load center LC, so as to facilitate the selection of transformers in the low-voltage AC system of the plant. The capacity determination method based on full-load current disclosed in the present disclosure is not limited by the type of equipment, and is closer to the actual needs in the working scene of the power plant, improves the accuracy of transformer selection, ensures the safety of the power plant, and ensures the economy of transformer selection.

[0125] Figure 3 A schematic diagram of a capacity design device for a low-voltage AC system of a power plant provided by an embodiment of the present disclosure. The low-voltage AC system includes a load center LC, a motor control center MCC, a first device, and a second device. The load center LC supplies power to the motor control center MCC and the first device, and the motor control center MCC supplies power to the second device. Figure 2 .like Figure 3 As shown, the capacity design device of the low-voltage AC system of the power plant includes: a first determination module 301 , a second determination module 302 , a third determination module 303 , a fourth determination module 304 and a fifth determination module 305 .

[0126] The first determination module 301 is used to determine the required load of the motor control center MCC according to the demand coefficient, full load current and rated voltage corresponding to the second device. The demand coefficient is used to indicate the ratio of the load demand of the device to the full load.

[0127] The second determination module 302 is used to determine the design load of the motor control center MCC according to the required load of the motor control center MCC and the first design margin.

[0128] The third determination module 303 is used to determine the calculated load of the first device according to the demand factor, full load current and rated voltage corresponding to the first device.

[0129] The fourth determination module 304 is used to determine the calculated total load of the load center LC according to the design load of the motor control center MCC and the calculated load of the first device.

[0130] The fifth determination module 305 is used to determine the design capacity of the load center LC according to the calculated total load of the load center LC and the second design margin.

[0131] In some embodiments of the present disclosure, the required load of the motor control center MCC includes required active power, required reactive power and required capacity. The first determination module 301 is specifically used to determine the required load of the motor control center MCC according to the demand coefficient, full load current and rated voltage corresponding to the second device through the following formula:

[0132]

[0133] DL_kW=DL_kVA×pf2

[0134]

[0135] Total_DL_kW=∑DL_kW

[0136] Total_DL_kVAR=∑DL_kVAR

[0137]

[0138] Among them, DL_kVA represents the required capacity of the second device, DL_kW represents the required active power of the second device, DL_kVAR represents the required reactive power of the second device, Total_DL_kW represents the required active power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, DF2 is the demand coefficient corresponding to the second device, ph is the number of power phases of the second device, FLA2 is the full load current corresponding to the second device, Voltage2 is the rated voltage corresponding to the second device, and pf2 is the power factor of the second device.

[0139] In some embodiments of the present disclosure, the second determination module 302 is specifically used to determine the design load of the motor control center MCC according to the required load of the motor control center MCC and the first design margin through the following formula, including:

[0140] Design_kVA2=(1+DM1)×Total_DL_kVA

[0141] Design_kW2=(1+DM1)×Total_DL_kW

[0142] Design_kVAR2=(1+DM1)×Total_DL_kVAR

[0143] Among them, Design_kVA2 represents the design capacity of the motor control center MCC, Design_kW2 represents the design active power of the motor control center MCC, Design_kVAR2 represents the design reactive power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, and DM1 is the first design margin.

[0144] In some embodiments of the present disclosure, the calculated load of the first device includes calculated capacity, calculated active power, and calculated reactive power. The third determination module 303 is specifically used to determine the calculated load of the first device according to the demand factor, full load current, and rated voltage corresponding to the first device by the following formula:

[0145]

[0146] Design_kW1=Design_kVA1×pf1

[0147]

[0148] Among them, Design_kVA1 represents the calculated capacity of the first device, Design_kW1 represents the calculated active power of the first device, Design_kVAR1 represents the calculated reactive power of the first device, DF1 is the demand factor corresponding to the first device, FLA1 is the full load current corresponding to the first device, Voltage1 is the rated voltage corresponding to the first device, and pf1 is the power factor of the first device.

[0149] In some embodiments of the present disclosure, the fourth determination module 304 is specifically used to: determine the product of the design load of the motor control center MCC and the load diversity coefficient LDF2 of the motor control center MCC as the first calculated load of the motor control center MCC; determine the product of the calculated load of the first device and the load diversity coefficient LDF1 of the first device as the first calculated load of the first device; add the first calculated load of the motor control center MCC and the first calculated load of the first device to obtain the calculated total load of the load center LC; wherein, the load diversity coefficient LDF2 of the motor control center MCC = 1-DM1, and the load diversity coefficient LDF1 of the first device = 1.

[0150] In some embodiments of the present disclosure, the fourth determination module 304 is specifically configured to: take the sum of the design load of the motor control center MCC and the calculated load of the first device as the calculated total load of the load center LC.

[0151] In some embodiments of the present disclosure, the calculated total load of the load center LC includes the calculated active power, calculated reactive power and calculated capacity of the total load of the load center LC. The fifth determination module 305 is specifically used to determine the design capacity of the load center LC according to the calculated total load of the load center LC and the second design margin by the following formula:

[0152] TDL_kW with DM=(1+DM2)×Total DivL_kW

[0153] TDL_kVAR with DM=(1+DM2)×Total DivL_kVAR

[0154]

[0155] Among them, Total DivL_kW represents the calculated active power of the total load of the load center LC, Total DivL_kVAR represents the calculated reactive power of the total load of the load center LC, DM2 is the second design margin, TDL_kW with DM is the design active power of the total load of the load center LC, TDL_kVAR with DM is the design reactive power of the total load of the load center LC, and LCXFMR_Design_kVAwith DM is the design capacity of the load center LC.

[0156] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0157] In order to implement the above embodiments, the present disclosure also proposes an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0158] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0159] In order to implement the above embodiments, the present disclosure also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0160] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0161] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0162] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present disclosure includes additional implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present disclosure belong.

[0163] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0164] It should be understood that the various parts of the present disclosure can be implemented in hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0165] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0166] In addition, each functional unit in each embodiment of the present disclosure may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0167] The storage medium mentioned above may be a read-only memory, a disk or an optical disk, etc. Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present disclosure. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present disclosure.

Claims

1. A capacity design method for a low-voltage AC system of a power plant, wherein the low-voltage AC system comprises a load center LC, a motor control center MCC, a first device and a second device, wherein the load center LC supplies power to the motor control center MCC and the first device, and the motor control center MCC supplies power to the second device, characterized in that: The method comprises the following steps: Determine the required load of the motor control center MCC according to the demand factor, full load current and rated voltage corresponding to the second device; wherein the demand factor is used to represent the ratio of the load demand of the device to the full load; Determining a design load of the motor control center MCC according to a required load of the motor control center MCC and a first design margin; determining a calculated load of the first device according to a demand factor, a full load current, and a rated voltage corresponding to the first device; Determining a calculated total load of the load center LC based on the design load of the motor control center MCC and the calculated load of the first device; The design capacity of the load center LC is determined according to the calculated total load of the load center LC and the second design margin.

2. The method according to claim 1, characterized in that The required load of the motor control center MCC includes required active power, required reactive power and required capacity; the required load of the motor control center MCC is determined by the following formula according to the demand coefficient, full load current and rated voltage corresponding to the second device: DL_kW=DL_kVA×pf2 Total_DL_kW=∑DL_kW Total_DL_kVAR=∑DL_kVAR Among them, DL_kVA represents the required capacity of the second device, DL_kW represents the required active power of the second device, DL_kVAR represents the required reactive power of the second device, Total_DL_kW represents the required active power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, DF2 is the demand coefficient corresponding to the second device, ph is the number of power phases of the second device, FLA2 is the full load current corresponding to the second device, Voltage2 is the rated voltage corresponding to the second device, and pf2 is the power factor of the second device.

3. The method according to claim 2, characterized in that According to the required load of the motor control center MCC and the first design margin, the design load of the motor control center MCC is determined by the following formula, including: Design_kVA2=(1+DM1)×Total_DL_kVA Design_kW2=(1+DM1)×Total_DL_kW Design_kVAR2=(1+DM1)×Total_DL_kVAR Among them, Design_kVA2 represents the design capacity of the motor control center MCC, Design_kW2 represents the design active power of the motor control center MCC, Design_kVAR2 represents the design reactive power of the motor control center MCC, Total_DL_kVAR represents the required reactive power of the motor control center MCC, Total_DL_kVA represents the required capacity of the motor control center MCC, and DM1 is the first design margin.

4. The method according to claim 1, characterized in that: The calculated load of the first device includes calculated capacity, calculated active power and calculated reactive power; the calculated load of the first device is determined by the following formula according to the demand factor, full load current and rated voltage corresponding to the first device: Design_kW1=Design_kVA1×pf1 Among them, Design_kVA1 represents the calculated capacity of the first device, Design_kW1 represents the calculated active power of the first device, Design_kVAR1 represents the calculated reactive power of the first device, DF1 is the demand factor corresponding to the first device, FLA1 is the full load current corresponding to the first device, Voltage1 is the rated voltage corresponding to the first device, and pf1 is the power factor of the first device.

5. The method according to claim 1, characterized in that: Determining the calculated total load of the load center LC according to the design load of the motor control center MCC and the calculated load of the first device comprises: Determine the product of the design load of the motor control center MCC and the load diversity factor LDF2 of the motor control center MCC as the first calculated load of the motor control center MCC; Determine the product of the computing load of the first device and the load diversity coefficient LDF1 of the first device as the first computing load of the first device; Adding the first calculated load of the motor control center MCC and the first calculated load of the first device to obtain a calculated total load of the load center LC; Among them, the load diversity coefficient LDF2 of the motor control center MCC is LDF2=1-DM1, and the load diversity coefficient LDF1 of the first device is LDF1=1.

6. The method according to claim 1, characterized in that Determining the calculated total load of the load center LC according to the design load of the motor control center MCC and the calculated load of the first device comprises: The sum of the design load of the motor control center MCC and the calculated load of the first device is taken as the calculated total load of the load center LC.

7. The method according to any one of claims 1 to 6, characterized in that The calculated total load of the load center LC includes the calculated active power, calculated reactive power and calculated capacity of the total load of the load center LC; according to the calculated total load of the load center LC and the second design margin, the design capacity of the load center LC is determined by the following formula: TDL_kW with DM=(1+DM2)×Total DivL_kW TDL_kVAR with DM=(1+DM2)×Total DivL_kVAR Among them, Total DivL_kW represents the calculated active power of the total load of the load center LC, Total DivL_kVAR represents the calculated reactive power of the total load of the load center LC, DM2 is the second design margin, TDL_kW with DM is the design active power of the total load of the load center LC, TDL_kVAR with DM is the design reactive power of the total load of the load center LC, and LCXFMR_Design_kVA with DM is the design capacity of the load center LC.

8. A capacity design device for a low-voltage AC system in a power plant, the low-voltage AC system comprising a load center LC, a motor control center MCC, a first device and a second device, the load center LC supplies power to the motor control center MCC and the first device, and the motor control center MCC supplies power to the second device, characterized in that: The device comprises: A first determination module is used to determine the required load of the motor control center MCC according to the demand coefficient, full load current and rated voltage corresponding to the second device; wherein the demand coefficient is used to represent the ratio of the load demand of the device to the full load; A second determination module is used to determine the design load of the motor control center MCC according to the required load of the motor control center MCC and the first design margin; A third determination module is used to determine the calculated load of the first device according to the demand factor, full load current and rated voltage corresponding to the first device; a fourth determination module, configured to determine a calculated total load of the load center LC according to a design load of the motor control center MCC and a calculated load of the first device; The fifth determination module is used to determine the design capacity of the load center LC according to the calculated total load of the load center LC and the second design margin.

9. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 7 when executed by a processor.

Images