Method and device for compensating reactive power of generator in leading phase operation

Abstract

The disclosed embodiments provide a method and device for compensating reactive power during generator leading-phase operation. The method determines whether a generator under test at a hydropower station is subject to leading-phase operation constraints during operation; if so, determines the current operating mode of the generator under test; then installs a reactor on the high-voltage side of the generator under test, and determines the capacity of the installed reactor based on the current operating mode of the generator under test. This invention reduces investment, improves equipment utilization, reduces line losses, and automatically compensates for reactive power, thereby saving energy and improving operational quality.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hydropower generation, and in particular to a method and device for compensating reactive power of a generator in leading phase operation. Background Art

[0002] Voltage is a key indicator of power quality. It directly impacts grid stability, the safe operation of power equipment, line losses, industrial and agricultural safety, product quality, unit electricity consumption, and people's daily lives. Reactive power is a key factor influencing voltage quality. Voltage quality and reactive power are inextricably linked; voltage issues are essentially reactive power issues. Properly addressing reactive power compensation is crucial.

[0003] The power required to convert the electromagnetic field energy in an inductive element into electrical energy within a circuit. Alternatively, the reactive power of a power grid is the process of exchanging AC current with inductive or capacitive current. By connecting a device with a capacitive power load and an inductive power load in parallel in the same circuit, energy is exchanged between the two loads. In this way, the reactive power required by the inductive load can be compensated by the reactive power output by the capacitive load.

[0004] Many electrical devices in the power grid operate based on the principle of electromagnetic induction. During the energy conversion process, they create an alternating magnetic field. During each cycle, the power absorbed and released equals the power released. This power is called reactive power. In a power system, not only active power but also reactive power must be balanced.

[0005] The relationship between active power, reactive power, and apparent power is:

[0006]

[0007] Among them, S is the apparent power, P is the active power, Q is the reactive power, Angle is the power factor angle, It can be seen from the power triangle that under a certain active power, the power factor The smaller the value, the greater the reactive power required. If reactive power isn't provided by capacitors, it must be supplied by the transmission system. To meet power requirements, the capacity of the power supply lines and transformers must be increased. This not only increases investment and reduces equipment utilization, but also increases line losses. Therefore, automatic reactive power compensation is crucial for saving energy and improving operational quality. Summary of the Invention

[0008] The present disclosure provides a method and device for compensating reactive power of a generator in leading phase operation, aiming to automatically compensate for reactive power to save electric energy and improve operation quality.

[0009] The technical solutions disclosed in this disclosure are as follows:

[0010] In a first aspect, an embodiment of the present disclosure provides a method for compensating reactive power of a generator in leading phase operation, comprising:

[0011] Determine whether the generator under test of the hydropower station is subject to the phase-leading operation constraint during operation;

[0012] If the answer is yes, then determine the current operating mode of the generator under test;

[0013] Install a reactor on the high-voltage side of the generator under test, and determine the capacity of the installed reactor based on the current operating mode of the generator under test.

[0014] In one possible implementation, in the method provided in an embodiment of the present invention, the leading phase operation constraint conditions include at least: limitation on the static stability of the generator, limitation on the temperature rise of the generator stator end core and metal structural parts, limitation on the generator stator current, limitation on the leading phase depth due to low excitation, and limitation on the system voltage.

[0015] In one possible implementation, in the method provided by an embodiment of the present invention, the operation mode of the generator includes a low mode in a flood season, a high mode in a dry season, and a low mode in a dry season.

[0016] In one possible implementation, the method provided in an embodiment of the present invention determines whether a generator under test of a hydropower station is restricted by static stability during operation, including:

[0017] Keep the active power of the generator under test constant, reduce the excitation current, and make the generator run in the leading phase. The corresponding power angle characteristic curve gradually decreases, and the power angle gradually increases. That is, the power angle stability margin decreases, and the static stability reserve coefficient also decreases accordingly, weakening the static stability capability of the generator until it reaches the critical stability state.

[0018] The power angle δ = 90° is used as the critical condition for static stability to maintain system stability. If the excitation current is further reduced, the unit will lose stability.

[0019] At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the static stability limit of the generator power angle.

[0020] In one possible implementation, the method provided in an embodiment of the present invention determines whether a generator under test of a hydropower station is limited by the temperature rise of the stator end iron core and metal structural components of the generator during operation, including:

[0021] When the generator is running, the end leakage magnetic flux of the stator winding generated at the end and the end leakage magnetic flux of the rotor winding form a closed circuit through magnetic resistance. When the rotating leakage magnetic field cuts the stationary stator end and various metal structural parts, it will induce eddy currents in them, generating hysteresis loss and eddy current loss, causing heat;

[0022] During delayed phase operation, the stator current is a demagnetizing armature reaction, while during advanced phase operation, the stator current is an increasing armature reaction. The synthetic leakage flux at the stator end of the generator increases. As the advanced phase power increases, the synthetic leakage flux gradually increases. Due to the increased magnetic flux passing through the core components at the stator end, when the components are not cooled sufficiently, the local temperature rise may be too high, and even exceed the temperature limit.

[0023] At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the temperature rise of the iron core and metal structural parts at the end of the generator stator.

[0024] In one possible implementation, the method provided in an embodiment of the present invention determines whether a generator under test of a hydropower station is limited by stator current during operation, including:

[0025] When the generator is running in the leading phase, the system absorbs reactive power and the generator terminal voltage decreases. When the generator active power is maintained unchanged, the stator current will increase. In severe cases, it will exceed the stator rated current, causing the stator winding temperature to rise.

[0026] At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the stator current.

[0027] In one possible implementation, the method provided in an embodiment of the present invention determines whether the generator under test of a hydropower station is limited in phase advance depth by low excitation during operation, including:

[0028] When the generator is running in the leading phase, if the output power of the generator is kept constant, as the generator excitation current decreases, the generator no-load potential drops, the generator operating power angle will increase, resulting in a decrease in the generator stability margin and entering a dangerous area where it cannot operate stably;

[0029] Due to improper coordination between the protection settings and the low excitation control loop and the PID control loop in the excitation system, the generator experiences large reactive vibrations during phase-leading operation in the low excitation state due to issues with the excitation system.

[0030] At this time, it is determined that the adjustment range of the phase-leading operation of the generator under test is limited by the phase-leading depth caused by low excitation.

[0031] In one possible implementation, the method provided in an embodiment of the present invention determines whether a generator under test of a hydropower station is limited by system voltage during operation, including:

[0032] When the generator is running in phase advance, it absorbs reactive power from the system, causing the system voltage to drop;

[0033] If the system capacity is small or the reactive power reserve is insufficient, the bus voltage on the high-voltage side of the step-up transformer at the generator end and the voltage at other nearby points will be lower than the allowable value, thus destroying the stable operation of the system and the generator, and even causing the system voltage to collapse and cause the system to disintegrate;

[0034] At this time, it is determined that the adjustment range of the leading phase operation of the generator under test is limited by the system voltage.

[0035] In one possible implementation, the method provided in an embodiment of the present invention determines the capacity of the installed reactor based on the current operating mode of the generator to be tested, including:

[0036] Assume that the reactive output of the generator set to be tested is 0MVar, calculate the reactive power that the busbar connected to the generator set to be tested needs to send theoretically, and combine it with the reactive power sent by the busbar actually monitored. The difference between the two is the capacity of the reactor that needs to be installed.

[0037] In a second aspect, an embodiment of the present disclosure further provides a generator leading phase operation reactive power compensation device, comprising:

[0038] The first judgment module is used to judge whether the generator under test of the hydropower station is subject to the phase-leading operation constraint during operation;

[0039] A second judgment module is used to judge the current operating mode of the generator to be tested when the first judgment module judges that it is yes;

[0040] The compensation module is used to install a reactor on the high-voltage side of the generator under test and determine the capacity of the installed reactor based on the current operating mode of the generator under test.

[0041] In a third aspect, an embodiment of the present disclosure further provides an electronic device, including:

[0042] processor;

[0043] a memory for storing processor-executable instructions;

[0044] The processor is configured to execute instructions to implement the method of the first aspect.

[0045] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the method of the first aspect when executed by a processor.

[0046] In a fifth aspect, an embodiment of the present disclosure further provides a computer program product, comprising a computer program / instruction, characterized in that the computer program / instruction implements the method of the first aspect when executed by a processor.

[0047] The technical solutions provided by the embodiments of the present disclosure bring at least the following beneficial effects:

[0048] In an embodiment of the present disclosure, a determination is made as to whether a generator under test at a hydropower station is subject to phase-leading constraints during operation. If so, the current operating mode of the generator under test is determined. A reactor is then installed on the high-voltage side of the generator under test, and the capacity of the installed reactor is determined based on the current operating mode of the generator under test. This invention reduces investment, improves equipment utilization, reduces line losses, automatically compensates for reactive power, conserves energy, and improves operational quality.

[0049] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the description are used to explain the principles of the present disclosure, and do not constitute an improper limitation of the present disclosure.

[0051] Figure 1 A flow chart of a method for reactive power compensation in leading phase operation of a generator provided by an embodiment of the present disclosure;

[0052] Figure 2 A schematic diagram of a phase-leading operation vector in a method for reactive power compensation of a generator in phase-leading operation provided by an embodiment of the present disclosure;

[0053] Figure 3 A schematic diagram of a generator power angle characteristic curve in a method for reactive power compensation of a generator in leading phase operation provided by an embodiment of the present disclosure;

[0054] Figure 4 A schematic diagram of a synchronous generator connected in parallel with an infinite bus in a method for reactive power compensation of a generator in leading phase operation provided by an embodiment of the present disclosure;

[0055] Figure 5 A schematic structural diagram of a reactive power compensation device for leading-phase operation of a generator provided by an embodiment of the present disclosure;

[0056] Figure 6 A schematic structural diagram of an electronic device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0057] In order to enable ordinary persons in the art to better understand the technical solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings.

[0058] It should be noted that the terms "first," "second," and the like in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this manner are interchangeable where appropriate so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure as detailed in the appended claims.

[0059] Figure 1 This is a flow chart of a method for compensating reactive power of a generator in phase leading operation provided by the first embodiment of the present disclosure, as shown in FIG. Figure 1 As shown, the method for compensating reactive power of the generator in leading phase operation may include the following steps:

[0060] S101, determining whether the generator to be tested of the hydropower station is subject to a phase-leading operation constraint during operation.

[0061] In the present invention, the leading phase operation constraint conditions include at least: limitation of the static stability of the generator, limitation of the temperature rise of the generator stator end core and metal structural parts, limitation of the generator stator current, limitation of the leading phase depth due to low excitation and limitation of the system voltage.

[0062] The basic requirement for reactive power balance in a power system is that the reactive power that can be generated by the reactive power sources in the system should be greater than or at least equal to the sum of the reactive power required by the load and the reactive power loss in the network. In order to ensure operational reliability and adapt to the growth of reactive loads, the system must also be equipped with a certain amount of reactive reserve capacity. Let Q GC is the sum of the reactive power supplied by the power supply, Q LD is the sum of reactive loads, Q L is the sum of the network reactive losses, Q res For reactive power backup, the balance relationship of reactive power in the system is:

[0063] Q GC -Q LD -Q L =Q res

[0064] Q res >0 means that the reactive power in the system can be balanced and there is an appropriate amount of reserve; Q res<0 means that the reactive power in the system is insufficient and the installation of reactive power compensation device should be considered.

[0065] When the generator is running with stator current that lags the terminal voltage, this normal operating condition is overexcitation, which is called delayed phase operation. The corresponding operating condition is forward phase operation, where the stator current leads the terminal voltage, which is called underexcitation.

[0066] When the generator is in the lagging phase operation and leading phase operation states, the common point between the two is that no matter which operating state the generator is in, there is active power. The difference is that the reactive power in the lagging phase operation state is inductive reactive power, while the leading phase reactive power is capacitive reactive power. When the two operating states are monitored online respectively, the power meter values ​​are also different.

[0067] According to power plant regulations, generator phase-leading operation is not considered a normal operating state; it is classified as an abnormal operating state, during which the generator absorbs inductive reactive power. However, in actual operation, phase-leading operation is considered merely a change in the generator's operating range, with the range increasing during operation. It is considered a normal operating condition with a fluctuating power factor. This is because during phase-leading operation, all systems of the generator maintain the same speed, and all electrical parameters remain symmetrical. Therefore, although power plant regulations define generator phase-leading operation as abnormal, in actual operation, as long as key parameters such as generator static stability, plant voltage, and heat generation do not exceed certain ranges, the generator can maintain phase-leading operation for extended periods to meet the normal needs of the power grid.

[0068] When the generator is connected to an infinite power grid, the terminal voltage U G Constant. Assume the potential of the generator is E0. If the excitation current I is adjusted f , in U G Under the condition that P remains unchanged, as E0 changes, the power factor angle also changes. When the excitation current is increased, E0 becomes larger, and at this time the load current I lags behind the terminal voltage U G , that is, the power factor angle is lagging, at this time the generator provides active power and reactive power to the system, that is, delayed phase operation. On the contrary, when the excitation current is reduced, so that E0 is reduced, the power factor becomes advanced, and at this time the generator outputs active power to the grid and absorbs reactive power, that is, advanced phase operation, such as Figure 2 As shown in the phase-advancing operation vector diagram.

[0069] When the generator is running with constant active power in the leading phase, it can be seen that the excitation current decreases and the induced electromotive force will also decrease accordingly. According to the static stability criterion, the system is stable if the increment direction of active power and power angle is consistent. Assume that the generator is running normally with active power P1 (ignoring armature resistance) and the induced electromotive force is E 01 , its power angle characteristic curve is as follows Figure 3 The three power angle characteristic curves in the figure correspond to E 01 、E 02 、E 03 The power angle characteristics under the condition of δ1, δ2 and δ3 are respectively used.

[0070] Specifically, determining whether the generator under test of the hydropower station is restricted by the static stability of the generator during operation includes:

[0071] Keep the active power of the generator under test constant, reduce the excitation current, and make the generator run in the leading phase. The corresponding power angle characteristic curve gradually decreases, and the power angle gradually increases. That is, the power angle stability margin decreases, and the static stability reserve coefficient also decreases accordingly, weakening the static stability capability of the generator until it reaches the critical stability state.

[0072] The power angle δ = 90° is used as the critical condition for static stability to maintain system stability. If the excitation current is further reduced, the unit will lose stability.

[0073] At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the static stability limit of the generator power angle.

[0074] The process of changing the operating status of the generator, such as Figure 4 As shown in the figure, keep the active power P1 value unchanged, adjust the excitation current, and the induced electromotive force E 01 The endpoints can only change along A1A4, and the endpoints of the stator current I1 can only change along the dotted line L1L2.

[0075] When the excitation current of the generator is gradually reduced, when the induced electromotive force becomes E 02 When the power angle increases to δ2, the power factor increases to The stator current decreases to I2. At this time, the generator only outputs active power and the reactive power is zero. Continue to reduce the generator excitation current, and the stator current begins to increase. When the induced electromotive force becomes E 03 When the power angle increases to δ3, the stator current increases to I3, but its nature has changed. At this time, I3 leads the terminal voltage U, and the generator changes from emitting reactive power to absorbing reactive power, that is, Q3 < 0. If the excitation current is further reduced, the induced electromotive force will decrease further, reaching E 04When the power angle δ≈90°, the stator current increases to I4, and the generator is in a critical stable state. A slight fluctuation will cause a loss of step. If the excitation current is gradually increased in the critical stable state, the generator operation state can be Then it switches to delayed phase operation and even restores the rated power factor operation.

[0076] The above analysis is based on the assumption that the generator is directly connected to an infinite power grid, that is, the external impedance is zero, that is, X s = 0. The following analysis considers the phase-advancing process when the reactance of the transformer, transmission line, and measuring element is equal, that is, when Xs ≠ 0. As the total system reactance increases, the static stability of the system decreases further.

[0077] Determine whether the generator under test at the hydropower station is limited by the temperature rise of the generator stator end core and metal structural parts during operation, including:

[0078] When the generator is running, the end leakage magnetic flux of the stator winding generated at the end and the end leakage magnetic flux of the rotor winding form a closed circuit through magnetic resistance. When the rotating leakage magnetic field cuts the stationary stator end and various metal structural parts, it will induce eddy currents in them, generating hysteresis loss and eddy current loss, causing heat;

[0079] During delayed phase operation, the stator current is a demagnetizing armature reaction, while during advanced phase operation, the stator current is an increasing armature reaction. The synthetic leakage flux at the stator end of the generator increases. As the advanced phase power increases, the synthetic leakage flux gradually increases. Due to the increased magnetic flux passing through the core components at the stator end, when the components are not cooled sufficiently, the local temperature rise may be too high, and even exceed the temperature limit.

[0080] At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the temperature rise of the iron core and metal structural parts at the end of the generator stator.

[0081] When the generator is running synchronously, the stator end leakage flux is a synthetic magnetic flux composed of the rotor winding end leakage flux and the stator three-phase winding end leakage flux. It is a synthetic magnetic field that rotates at the same speed as the rotor. Its size is related to the generator manufacturing process such as the power factor, stator current size, end structure, and stator winding structure.

[0082] Determine whether the generator under test of the hydropower station is limited by the stator current during operation, including:

[0083] When the generator is running in the leading phase, the system absorbs reactive power and the generator terminal voltage decreases. When the generator active power is maintained unchanged, the stator current will increase. In severe cases, it will exceed the stator rated current, causing the stator winding temperature to rise.

[0084] At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the stator current.

[0085] Determine whether the generator under test at the hydropower station is limited in phase advance depth by low excitation during operation, including:

[0086] When the generator is running in the leading phase, if the output power of the generator is kept constant, as the generator excitation current decreases, the generator no-load potential drops, the generator operating power angle will increase, resulting in a decrease in the generator stability margin and entering a dangerous area where it cannot operate stably;

[0087] Due to improper coordination between the protection settings and the low excitation control loop and the PID control loop in the excitation system, the generator experiences large reactive vibrations during phase-leading operation in the low excitation state due to issues with the excitation system.

[0088] At this time, it is determined that the adjustment range of the phase-leading operation of the generator under test is limited by the phase-leading depth caused by low excitation.

[0089] Determine whether the generator under test at the hydropower station is limited by the system voltage during operation, including:

[0090] When the generator is running in phase advance, it absorbs reactive power from the system, causing the system voltage to drop;

[0091] If the system capacity is small or the reactive power reserve is insufficient, the bus voltage on the high-voltage side of the step-up transformer at the generator end and the voltage at other nearby points will be lower than the allowable value, thus destroying the stable operation of the system and the generator, and even causing the system voltage to collapse and cause the system to disintegrate;

[0092] At this time, it is determined that the adjustment range of the leading phase operation of the generator under test is limited by the system voltage.

[0093] Leading-phase operation of hydro-turbine generators can absorb excess reactive power from the grid and reduce system voltage. It is a practical operational technology tailored to the needs of power generation. Most importantly, it achieves voltage reduction simply by changing the operating conditions of the hydro-turbine generators. This utilizes existing system equipment to regulate system voltage and improve grid voltage quality. This method is simple to operate, reliable within the limits of leading-phase operation of hydro-turbine generators, and offers smooth and stepless voltage regulation, offering great flexibility. Therefore, leading-phase operation of hydro-turbine generators is one of the most effective and necessary measures to improve grid voltage quality.

[0094] Leading phase operation of large hydro-generators is a normal underexcited synchronous operating state. Their ability to generate capacitive reactive power, or the leading depth of the generator, is constrained by multiple factors, including the static stability of the generator set, stator overcurrent, heating of the stator core and structural components at the ends, and reduced power supply voltage at the power plant. The static stability of a hydro-generator is related not only to the generator's inherent design parameters but also to the power system structure and operating mode, the performance of the selected excitation regulator, and the setting of operating and protection parameters. Power companies generally conduct relevant analyses. The temperature rise at the ends of the generator, on the other hand, is directly related to the generator's design and manufacture, and is therefore crucial to its operational safety and lifespan. In recent years, in order to meet the market demand for the leading phase operation capability of hydro-generators, Dongfang Electric has taken a series of measures in electromagnetic design and structural design when conducting optimization design of large hydro-generators and hydro-generators, combining the results of special research and the experience of on-site leading phase operation tests. These measures have further improved the static stability of hydro-generators, reduced the temperature rise at the ends of hydro-generators, and are more conducive to the leading phase operation of hydro-generators.

[0095] S102: If the answer is yes, determine the current operating mode of the generator to be tested.

[0096] The operating modes of the generator include low mode in flood season, high mode in dry season and low mode in dry season.

[0097] S103: Install a reactor on the high-voltage side of the generator to be tested, and determine the capacity of the installed reactor based on the current operating mode of the generator to be tested.

[0098] Assume that the reactive output of the generator set to be tested is 0MVar, calculate the reactive power that the busbar connected to the generator set to be tested needs to send theoretically, and combine it with the reactive power sent by the busbar actually monitored. The difference between the two is the capacity of the reactor that needs to be installed.

[0099] In a specific embodiment of the present invention,

[0100] During low-power operation during the flood season, as the flood season has just begun, the generators are still required to operate in a phase-leading mode to maintain the hydropower station's high-voltage bus voltage within the specified limits. Under this operating mode, the depth of phase-leading operation of the generator sets is mostly concentrated around 50%, with a relatively deep phase-leading degree, and no generator sets operate outside the underexcitation limit. Analysis indicates that the generator set's high-voltage line influences whether and to what extent the generator sets operate in this mode. At this time, the reactive power transmitted to the hydropower station's high-voltage bus by this high-voltage line was 65.8 MVar. Therefore, to maintain the high-voltage bus voltage within the specified limits, the generators must maintain a relatively deep phase-leading depth.

[0101] During low-power operation during the flood season, the generator sets are in phase-leading mode, and the high-voltage bus output power is set to (315.0000 - j59.6000) MVA. Calculations show that when the generator sets are in phase-leading mode, the high-voltage bus output power is (314.5802 - j0.0855) MVA. Based on the reactive power balance formula, a reactor with a capacity of 59.5145 Mvar is theoretically required on the high-voltage transformer side.

[0102] During the dry season, the generator set is in operation mode. According to the high-voltage line flow analysis, the reactive power sent to the high-voltage busbar by this line is 9.8MVar. The Sanghe high-voltage busbar absorbs less reactive power, so the generator set needs to absorb less reactive power and the phase advance degree is shallow.

[0103] During dry season operation, the generator sets are in phase-leading mode, and the high-voltage bus output power is set to (165.0000 + j1.0000) MVA. Calculations show that when the generator sets are in phase-leading mode, the high-voltage bus output power is (164.6517 + j4.5536) MVA. Based on the reactive power balance formula, a reactor with a capacity of 3.5536 Mvar is theoretically required on the high-voltage transformer side of the generator sets.

[0104] The characteristics of generator set operation during low-power operation during the dry season are very obvious. During this period, the generator set is in a deep phase-leading state, and the phase-leading degree is relatively stable and concentrated around 80%. With such a deep phase-leading degree, it is necessary to consider the static stability of the generator set and to ensure that the temperature of each component does not exceed the limit.

[0105] During dry season operation, the generator sets are in phase-leading mode, and the high-voltage bus output power is set to (38.0000 - j23.5000) MVA. Calculations show that when the generator sets are in phase-leading mode, the high-voltage bus output power is (37.6925 + j21.3645) MVA. Based on the reactive power balance formula, a reactor with a capacity of 44.6645 Mvar is theoretically required on the high-voltage transformer side of the generator sets.

[0106] Based on the same inventive concept, the embodiment of the present disclosure also provides a generator leading phase operation reactive power compensation device. Figure 5 As shown, the generator leading phase operation reactive power compensation device 500 includes:

[0107] The first judgment module 510 is used to judge whether the generator under test of the hydropower station is subject to the leading phase operation constraint during operation;

[0108] The second judgment module 520 is used to judge the current operating mode of the generator under test when the first judgment module judges that the current operating mode of the generator under test is yes;

[0109] The compensation module 530 is used to install a reactor on the high-voltage side of the generator under test and determine the capacity of the installed reactor based on the current operating mode of the generator under test.

[0110] The specific implementation method and technical effects of the device provided by the embodiment of the present disclosure are similar to those of the above-mentioned method embodiment, and will not be repeated here.

[0111] In addition, combined Figure 1-Figure 5 The battery capacity prediction method and apparatus described in the embodiments of the present application may be implemented by an electronic device. Figure 6 A schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present application is shown.

[0112] like Figure 6 As shown, the electronic device 1000 may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 1001, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1008 into a random access memory (RAM) 1003 to implement the battery capacity prediction method of the embodiment described in the present disclosure. Various programs and data required for the operation of the electronic device 1000 are also stored in the RAM 1003. The processing device 1001, the ROM 1002, and the RAM 1003 are connected to each other via a bus 1004. An input / output (I / O) interface 1005 is also connected to the bus 1004.

[0113] Typically, the following devices may be connected to the I / O interface 1005: an input device 1006 including, for example, a touch screen, a touchpad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 1007 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 1008 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 may allow the electronic device 1000 to communicate with other devices wirelessly or by wire to exchange data. Figure 6 The electronic device 1000 is shown with various devices, but it should be understood that it is not required to implement or possess all of the devices shown. More or fewer devices may be implemented or possessed instead.

[0114] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a non-transitory computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart, thereby implementing the voice control method as described above. In such an embodiment, the computer program can be downloaded and installed from the network through the communication device 1009, or installed from the storage device 1008, or installed from the ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment of the present disclosure are performed.

[0115] It should be noted that the computer-readable medium mentioned above in the present disclosure may be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device, or component. In the present disclosure, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wires, optical cables, RF (radio frequency), etc., or any suitable combination thereof.

[0116] In some embodiments, the client and server can communicate using any currently known or future developed network protocol, such as HTTP (HyperText Transfer Protocol), and can be interconnected with any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network ("LAN"), a wide area network ("WAN"), an internet (e.g., the Internet), and a peer-to-peer network (e.g., an ad hoc peer-to-peer network), as well as any currently known or future developed network.

[0117] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0118] The computer-readable medium carries one or more programs. When the one or more programs are executed by the electronic device, the electronic device:

[0119] Determine whether the generator under test of the hydropower station is subject to the phase-leading operation constraint during operation;

[0120] If the answer is yes, then determine the current operating mode of the generator under test;

[0121] Install a reactor on the high-voltage side of the generator under test, and determine the capacity of the installed reactor based on the current operating mode of the generator under test.

[0122] Optionally, when the above one or more programs are executed by the electronic device, the electronic device may also execute other steps described in the above embodiments.

[0123] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages, or a combination thereof, including, but not limited to, object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0124] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the module, program segment, or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0125] The units involved in the embodiments described in this disclosure may be implemented in software or hardware, wherein the name of a unit does not necessarily limit the unit itself.

[0126] The functions described above herein may be performed, at least in part, by one or more hardware logic components. For example, and without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chip (SOCs), complex programmable logic devices (CPLDs), and the like.

[0127] In the context of the present disclosure, a machine-readable medium can be a tangible medium that can contain or store a program for use by or in conjunction with an instruction execution system, device or equipment. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium can include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0128] The battery capacity prediction method mentioned in the embodiment of the present invention includes:

[0129] In the disclosed embodiments, a fully charged battery under test is first discharged at a constant current to determine the discharge capacity. The open-circuit voltage of the battery under test is then measured, and the remaining battery capacity is predicted based on the relationship between the open-circuit voltage and the remaining battery capacity. Finally, the battery capacity of the battery under test is determined based on the remaining battery capacity and the discharge capacity. This provides a battery capacity prediction solution that, utilizing the pre-fitted relationship between the open-circuit voltage and the remaining battery capacity, accurately predicts the battery capacity of the battery under test with a single discharge. This effectively shortens the capacity testing process, ensures continuous production, and saves energy.

[0130] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0131] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0132] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0133] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1A step that specifies a function in one or more boxes.

[0134] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0135] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for compensating reactive power of a generator in leading phase operation, characterized in that: include: Determine whether the generator under test of the hydropower station is subject to phase-leading operation constraints during operation, wherein the phase-leading operation constraints include at least: limitations on the static stability of the generator, limitations on the temperature rise of the iron core and metal structural components of the generator stator end, limitations on the stator current of the generator, limitations on the phase-leading depth due to low excitation, and limitations on the system voltage; If the answer is yes, the current operating mode of the generator to be tested is determined, where the operating modes of the generator include a low operating mode in a flood season, a high operating mode in a dry season, and a low operating mode in a dry season; Installing a reactor on the high-voltage side of the generator to be tested, and determining the capacity of the installed reactor based on the current operating mode of the generator to be tested; Determining the capacity of the installed reactor based on the current operating mode of the generator to be tested includes: Assume that the reactive output of the generator set to be tested is 0MVar, calculate the reactive power that the busbar connected to the generator set to be tested needs to send theoretically, and combine it with the reactive power sent by the busbar actually monitored. The difference between the two is the capacity of the reactor that needs to be installed.

2. The method for compensating reactive power of a generator in phase leading operation according to claim 1, characterized in that: Determine whether the generator under test at the hydropower station is restricted by the static stability of the generator during operation, including: Maintaining the active power of the generator under test constant, reducing the excitation current, and making the generator run in leading phase, the corresponding power angle characteristic curve gradually decreases, and the power angle gradually increases, that is, the power angle stability margin decreases, and the static stability reserve coefficient also decreases accordingly, weakening the static stability capability of the generator until it reaches a critical stability state; The power angle δ = 90° is used as the critical condition for static stability to maintain system stability. If the excitation current is further reduced, the unit will lose stability. At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the static stability limit of the generator power angle.

3. The method for compensating reactive power of a generator in leading phase operation according to claim 1, characterized in that: Determine whether the generator under test at the hydropower station is limited by the temperature rise of the generator stator end core and metal structural parts during operation, including: When the generator is running, the end leakage magnetic flux of the stator winding generated at the end and the end leakage magnetic flux of the rotor winding form a closed circuit through magnetic resistance. When the rotating leakage magnetic field cuts the stationary stator end and various metal structural parts, it will induce eddy currents in them, generating hysteresis loss and eddy current loss, causing heat; During delayed phase operation, the stator current is a demagnetizing armature reaction, while during advanced phase operation, the stator current is an increasing armature reaction. The synthetic leakage flux at the stator end of the generator increases. As the advanced phase power increases, the synthetic leakage flux gradually increases. Due to the increased magnetic flux passing through the core components at the stator end, when the components are not cooled sufficiently, the local temperature rise may be too high, and even exceed the temperature limit. At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the temperature rise of the iron core and metal structural parts at the end of the generator stator.

4. The method for compensating reactive power of a generator in phase leading operation according to claim 1, characterized in that: Determine whether the generator under test of the hydropower station is limited by the stator current during operation, including: When the generator is running in the leading phase, the system absorbs reactive power and the generator terminal voltage decreases. When the generator active power is maintained unchanged, the stator current will increase. In severe cases, it will exceed the stator rated current, causing the stator winding temperature to rise. At this time, it is determined that the adjustment range of the leading phase operation of the generator to be tested is limited by the stator current.

5. The method for compensating reactive power of a generator in leading phase operation according to claim 1, characterized in that: Determine whether the generator under test at the hydropower station is limited in phase advance depth by low excitation during operation, including: When the generator is running in the leading phase, if the output power of the generator is kept constant, as the generator excitation current decreases, the generator no-load potential drops, the generator operating power angle will increase, resulting in a decrease in the generator stability margin and entering a dangerous area where it cannot operate stably; Due to improper coordination between the protection settings and the low excitation control loop and the PID control loop in the excitation system, the generator experiences large reactive vibrations during phase-leading operation in the low excitation state due to issues with the excitation system. At this time, it is determined that the adjustment range of the phase-leading operation of the generator to be tested is limited by the phase-leading depth due to low excitation.

6. The method for compensating reactive power of a generator in leading phase operation according to claim 1, characterized in that: Determine whether the generator under test at the hydropower station is limited by the system voltage during operation, including: When the generator is running in phase advance, it absorbs reactive power from the system, causing the system voltage to drop; If the system capacity is small or the reactive power reserve is insufficient, the bus voltage on the high-voltage side of the step-up transformer at the generator end and the voltage at other nearby points will be lower than the allowable value, thus destroying the stable operation of the system and the generator, and even causing the system voltage to collapse and cause the system to disintegrate; At this time, it is determined that the adjustment range of the phase-leading operation of the generator to be tested is limited by the system voltage.

7. A reactive power compensation device for a generator in leading phase operation, characterized in that: include: A first judgment module is used to judge whether the generator under test of the hydropower station is subject to phase-leading operation constraints during operation, wherein the phase-leading operation constraints include at least: limitations on the static stability of the generator, limitations on the temperature rise of the iron core and metal structural parts of the generator stator end, limitations on the stator current of the generator, limitations on the phase-leading depth due to low excitation, and limitations on the system voltage; A second judgment module is configured to judge the current operating mode of the generator under test when the first judgment module judges that the result is yes, wherein the operating modes of the generator include a low operating mode in a flood season, a high operating mode in a dry season, and a low operating mode in a dry season; a compensation module, configured to install a reactor on the high-voltage side of the generator under test and determine the capacity of the installed reactor based on the current operating mode of the generator under test; The compensation module is also used to make the reactive output of the generator set to be tested 0MVar, calculate the reactive power that the busbar connected to the generator set to be tested theoretically needs to send, and combine it with the reactive power actually monitored by the busbar. The difference between the two is the capacity of the inductor that needs to be installed.

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