Phase-shifting transformer secondary side short circuit fault detection method, device and equipment
By calculating and controlling the voltage and current of the phase shift transformer, and determining the secondary side short circuit, the problems of high cost of secondary side short circuit protection and difficulty in identification in the prior art are solved, and fast and accurate short circuit fault detection is achieved.
Patent Information
- Application Number
- CN202510070363.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-05-02
AI Technical Summary
In the prior art, the short-circuit protection cost of the secondary side of the phase-shift transformer is high, and short-circuit recognition is difficult, making it difficult to accurately determine whether the secondary side is short-circuited.
By obtaining the effective voltage value, active current and reactive current of the phase shift transformer, the maximum allowable value of the reactive current is calculated, and the short-circuit current is output through PI control. When the short-circuit current is less than the preset protection current, it is determined that the secondary side is short-circuited.
It is realized that the reactive component of the primary current of the phase-shift transformer is used to determine whether the secondary side is short-circuited by the reactive component of the primary current of the phase-shift transformer without adding additional costs, avoiding errors caused by reactive current fluctuations or interference, and quickly and accurately completing short-circuit fault detection.
Smart Images
Figure CN119916255A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of phase-shifting transformer protection, and in particular to a method, device and equipment for detecting a secondary short-circuit fault of a phase-shifting transformer. Background Art
[0002] High-voltage inverters are widely used in industries such as metallurgy and power generation, and have significant energy-saving effects. At present, most high-voltage inverters are power unit cascade inverters, and the phase-shifting transformer is the main component of the high-voltage inverter. Depending on the output voltage of the high-voltage inverter, the number of secondary windings of the phase-shifting transformer is also different. When the output voltage is 6kV, 15 secondary windings are usually required; when the output voltage is 10kV, 24 secondary windings are usually required.
[0003] The secondary windings of the phase-shifting transformer supply power to multiple power units in the high-voltage inverter. The secondary short-circuit impedance is generally designed to be around 2%-5%. Once a short circuit occurs inside the power unit or directly between the secondary windings, the secondary current will reach more than 20 times the rated current, generating huge energy that can easily burn the transformer.
[0004] In the related art, protection can be performed by detecting the current of each secondary winding, or by detecting the primary current of the phase-shifting transformer.
[0005] However, for the method of detecting the current of each secondary winding, due to the large number of secondary windings, for example, a high-voltage inverter with a 10kV output usually has 24 secondary windings, this method requires an additional 72 current transformers, which not only increases the cost, but also increases the burden on the control system, and has poor reliability. For the method of detecting the primary current of the phase-shifting transformer, for the phase-shifting transformer, when a secondary winding is short-circuited, the short-circuit current of the secondary winding is large (more than 20 times the rated current), but its primary current is not large, so it is difficult to accurately identify. In addition, the short-circuit current time that the phase-shifting transformer can withstand is within 250ms, and the primary current protection is often too late. Moreover, after the secondary side is short-circuited, due to the large short-circuit current, it will be disconnected after a long time, which leads to the failure of the primary side protection. Summary of the invention
[0006] The present application provides a method, device and equipment for detecting short-circuit faults on the secondary side of a phase-shifting transformer, which can solve the technical problems in the prior art of high cost of short-circuit protection of the secondary side of the phase-shifting transformer and difficulty in identifying short circuits.
[0007] In a first aspect, the present application provides a method for detecting a secondary short-circuit fault of a phase-shifting transformer, the method comprising:
[0008] Obtaining the effective value of the voltage, active current and reactive current of the phase-shifting transformer;
[0009] According to the above voltage effective value and active current, obtain the maximum allowable value of reactive current;
[0010] Obtain the difference between the maximum allowable value of the reactive current and the reactive current to perform PI control and output a short-circuit current;
[0011] When the short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited.
[0012] In combination with the first aspect, in one implementation, obtaining the effective value of the voltage of the phase-shifting transformer specifically includes:
[0013] Obtaining the primary voltage of the phase-shifting transformer;
[0014] The effective value of the voltage is obtained based on the above primary voltage.
[0015] In combination with the first aspect, in one implementation, obtaining the active current and reactive current of the phase-shifting transformer specifically includes:
[0016] Obtain the primary current of the phase-shifting transformer;
[0017] The above primary current is transformed through 3S / 2r coordinate transformation to obtain active current and reactive current.
[0018] In combination with the first aspect, in one implementation, the maximum allowable reactive current value I qmaxset for:
[0019]
[0020] Where Erms is the effective value of voltage, I d is the active current, k1 is a constant, and k2 is a coefficient related to the short-circuit impedance of the phase-shifting transformer.
[0021] In combination with the first aspect, in one implementation, when the short-circuit current is less than a preset short-circuit protection current, the method further includes:
[0022] Set the transformer short-circuit protection flag to 1; the signal with the flag at 1 is the tripping action signal of the upper switch of the phase-shifting transformer.
[0023] In combination with the first aspect, in one implementation, after outputting the short-circuit current, the method further includes:
[0024] comparing the short-circuit current with the short-circuit protection current; and,
[0025] When the short-circuit current is greater than or equal to the short-circuit protection current, the transformer short-circuit protection flag is set to 0.
[0026] In a second aspect, the present application provides a phase-shifting transformer secondary short-circuit fault detection device, the device comprising:
[0027] A voltage and current acquisition unit, which is used to obtain the primary voltage and primary current of the phase-shifting transformer;
[0028] A short-circuit protection judgment unit, which is used to obtain a voltage effective value according to the above-mentioned primary voltage, and to obtain an active current and a reactive current according to the above-mentioned primary current; and to obtain a maximum allowable value of the reactive current according to the above-mentioned voltage effective value and the active current;
[0029] The short-circuit protection judgment unit is also used to obtain the difference between the maximum allowable value of the reactive current and the reactive current to perform PI control and output the short-circuit current; and when the short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited.
[0030] In conjunction with the second aspect, in one implementation, the short circuit protection judgment unit includes:
[0031] An effective value calculation module, which is used to obtain the effective value of the voltage according to the above primary voltage;
[0032] A coordinate transformation module, which is used to obtain active current and reactive current according to the primary current;
[0033] A reactive current maximum allowable value calculation module, which is used to obtain the reactive current maximum allowable value according to the above voltage effective value and active current;
[0034] A difference calculation module, which is used to obtain the difference between the maximum allowable value of the reactive current and the reactive current;
[0035] A PI regulation controller module, which is used to output a short-circuit current according to the difference;
[0036] A comparison and judgment module is used to compare the magnitudes of the short-circuit current and the short-circuit protection current, and when the short-circuit current is smaller than a preset short-circuit protection current, determine that the secondary side of the phase-shifting transformer is short-circuited.
[0037] In conjunction with the second aspect, in one embodiment, the above-mentioned device further includes:
[0038] The flag unit is used to set the transformer short-circuit protection flag position to 1 when the short-circuit current is less than the preset short-circuit protection current, and to set the transformer short-circuit protection flag position to 0 when the short-circuit current is greater than or equal to the preset short-circuit protection current.
[0039] In the third aspect, the present application provides a phase-shifting transformer secondary short-circuit fault detection device, the above-mentioned phase-shifting transformer secondary short-circuit fault detection device includes a processor, a memory, and a phase-shifting transformer secondary short-circuit fault detection program stored in the above-mentioned memory and executable by the above-mentioned processor, wherein when the above-mentioned phase-shifting transformer secondary short-circuit fault detection program is executed by the above-mentioned processor, the steps of the above-mentioned phase-shifting transformer secondary short-circuit fault detection method are implemented.
[0040] The beneficial effects of the technical solution provided by this application include:
[0041] After obtaining the effective value of the voltage, as well as the active current and the reactive current of the phase-shifting transformer, the maximum allowable value of the reactive current is obtained according to the above effective value of the voltage and the active current, and then the difference between the maximum allowable value of the reactive current and the above reactive current can be obtained for PI control, and the short-circuit current is output. The short-circuit current and the preset short-circuit protection current are compared. When the short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited. This achieves the determination of whether the secondary side is short-circuited by the reactive component of the primary current of the phase-shifting transformer without increasing additional costs, avoids errors caused by reactive current fluctuations or interference, quickly and accurately completes short-circuit fault detection, and solves the technical problems of high cost of short-circuit protection of the secondary side of the phase-shifting transformer and difficulty in short-circuit identification in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] Figure 1 A flow chart of an embodiment of a method for detecting a secondary short-circuit fault of a phase-shifting transformer according to the present application;
[0043] Figure 2 The waveform diagram of the primary current active current, reactive current and power factor when the secondary side is short-circuited in this application;
[0044] Figure 3 A flow chart of another embodiment of a method for detecting a secondary short-circuit fault of a phase-shifting transformer according to the present application;
[0045] Figure 4 This is a functional module diagram of an embodiment of a phase-shifting transformer secondary short-circuit fault detection device of the present application;
[0046] Figure 5 Schematic diagram of the hardware structure of the phase-shifting transformer secondary short-circuit fault detection device involved in the embodiment of the present application. DETAILED DESCRIPTION
[0047] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0048] In a first aspect, an embodiment of the present application provides a method for detecting a secondary short-circuit fault of a phase-shifting transformer.
[0049] In one embodiment, referring to Figure 1 , the secondary short-circuit fault detection method of the phase-shifting transformer includes:
[0050] S1. Obtain the effective value of the voltage of the phase-shifting transformer, as well as the active current and reactive current;
[0051] S2. Obtain the maximum allowable value of reactive current based on the above voltage RMS and active current;
[0052] S3. Obtain the difference between the maximum allowable value of the reactive current and the reactive current for PI control and output short-circuit current;
[0053] S4. When the short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited.
[0054] In this embodiment, after obtaining the effective value of the voltage, and the active current and reactive current of the phase-shifting transformer, the maximum allowable value of the reactive current is obtained according to the above effective value of the voltage and the active current, and then the difference between the maximum allowable value of the reactive current and the above reactive current can be obtained for PI control, and the short-circuit current is output. The short-circuit current and the preset short-circuit protection current are compared. When the above short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited. This realizes the determination of whether the secondary side is short-circuited by the reactive component of the primary current of the phase-shifting transformer without increasing additional costs, and avoids errors caused by reactive current fluctuations or interference, quickly and accurately completes short-circuit fault detection, and solves the technical problems of high cost of short-circuit protection of the secondary side of the phase-shifting transformer and difficulty in short-circuit identification in the prior art.
[0055] Further, in one embodiment, in the above step S1, obtaining the effective value of the voltage of the phase-shifting transformer specifically includes:
[0056] First, the primary voltage of the phase-shifting transformer is obtained;
[0057] Then, the effective value of the voltage is obtained according to the above primary voltage.
[0058] In this embodiment, by collecting the primary voltages Ua, Ub, and Uc of the phase-shifting transformer, the corresponding voltage effective values can be obtained by calculation.
[0059] Further, in one embodiment, in the above step S1, obtaining the active current and reactive current of the phase-shifting transformer specifically includes:
[0060] First, obtain the primary current of the phase-shifting transformer;
[0061] Then, the primary current is transformed through 3S / 2r coordinate transformation to obtain active current and reactive current.
[0062] In this embodiment, by collecting the primary currents Ia, Ib, and Ic of the phase-shifting transformer, the active current and the reactive current can be obtained through a three-phase stationary to two-phase rotating 3S / 2r coordinate transformation.
[0063] Based on the above embodiment, in this embodiment, the above maximum allowable value of reactive current I qmaxset for:
[0064]
[0065] Where Erms is the effective value of voltage, I d is the active current, k1 is a constant, and k1 is a constant related to the rated capacity of the phase-shifting transformer, and k2 is a coefficient related to the short-circuit impedance of the phase-shifting transformer, and the unit is ohm.
[0066] Optionally, in one embodiment, the above k1 and k2 may be obtained according to a pre-stored table of the relationship between the rated capacity and k1, and a pre-stored table of the relationship between the short-circuit impedance and k2.
[0067] In this embodiment, when detecting and judging the secondary short circuit under light load and heavy load conditions,
[0068] When the load is light, that is, the active current I d The corresponding maximum allowable value of reactive current is recorded as I qmaxset 1; When the load is heavy, the active current I d The corresponding maximum allowable value of reactive current is recorded as I qmaxset 2. According to the principle of the reactive current maximum value calculation module, I qmaxset 1 qmaxset 2.
[0069] Assuming that the load increases from light load to heavy load, if the maximum allowable value of reactive current is not adjusted, it will still be I qmaxset 1, when overload is working normally, I q will also increase, which may cause I qmaxset 1 is less than the reactive current I q , resulting in the input error of the PI regulation controller being a negative value, the output of the regulator will gradually decrease, and Isc will gradually decrease from the maximum value. When compared with the short-circuit protection current Iscset, the comparator output is 1, and the transformer short-circuit protection flag TransFormSCFlag is set to 1, resulting in malfunction of the short-circuit fault judgment.
[0070] Therefore, the maximum allowable value of reactive current I qmaxset The adjustment should be made according to the load conditions. Similarly, the adjustment should be made according to the voltage effective value Erms.
[0071] It is understandable that after the secondary side of the multi-secondary winding transformer is short-circuited, the transformer main flux does not change significantly, but it significantly affects the reactive power and negative sequence components of the primary current. The calculation formula for the primary active power and reactive power is shown as follows:
[0072] P=UaIacosα+UbIbcosα+UcIccosα
[0073] Q=UaIasinα+UbIbsinα+UcIcsinα
[0074] Among them, P is the active power of the transformer, Ua, Ub, Uc are the primary three-phase voltages, Ia, Ib, Ic are the primary three-phase currents, cosα is the power factor, Q is the reactive power of the transformer; sinα is the sinusoidal component.
[0075] Through simulation verification, it can be seen that when a single secondary winding short-circuit fault occurs in the phase-shifting transformer, the primary current of the transformer is close to the rated current, but the reactive power component increases significantly and the power factor decreases significantly.
[0076] Furthermore, if Figure 2 As shown in the figure, when the secondary side of the phase-shifting transformer is short-circuited, the reactive current fluctuates. Therefore, if we simply compare the reactive current with the set protection threshold to determine whether a secondary side short circuit occurs, then due to the feedback reactive current I q Fluctuations can easily cause false protection operations.
[0077] Therefore, the generated reactive current protection threshold and the actual reactive current can be controlled in an error closed-loop through closed-loop PI regulation, and the proportional link of the PI controller can adjust the protection action time. The integral link of the PI controller can cope with the fluctuation of reactive current. When the error link accumulates to saturation, the protection is activated. When interference occurs in reactive current detection, such as high-voltage closing introduces strong electromagnetic interference, affecting sampling, or the secondary short-circuit fault is non-continuous, such as metal powder particles suddenly fall between the windings, causing a short circuit, but the short circuit is eliminated immediately after being melted, the above-mentioned reactive current fluctuations or interference can also be eliminated through the integral link.
[0078] Furthermore, in one embodiment, in the above step S4, when the above short-circuit current is less than the preset short-circuit protection current, it also includes:
[0079] Set the transformer short-circuit protection flag to 1; the signal with the flag at 1 is the tripping action signal of the upper switch of the phase-shifting transformer.
[0080] Furthermore, in one embodiment, in the above step S3, after outputting the short-circuit current, the step further includes:
[0081] Compare the magnitudes of the short-circuit current and the short-circuit protection current.
[0082] Among them, when the above short-circuit current is greater than or equal to the above short-circuit protection current, the transformer short-circuit protection flag is set to 0.
[0083] like Figure 3 As shown, the above-mentioned phase-shifting transformer secondary short-circuit fault detection method specifically includes:
[0084] In the first step, the primary voltage Ua, Ub, Uc and the primary current Ia, Ib, Ic of the phase-shifting transformer are collected through the voltage and current collection unit; then, according to the primary voltage Ua, Ub, Uc, the voltage effective value Erms is calculated through the effective value calculation module, and according to the primary current Ia, Ib, Ic, the active current I is obtained by performing 3S / 2r coordinate transformation through the coordinate transformation module. d and reactive current I q .
[0085] The second step is to convert the voltage rms and active current I d The maximum allowable reactive current value is sent to the reactive current maximum allowable value calculation module, which calculates the maximum allowable reactive current value I according to the current voltage effective value Erms and active current. qmaxSet . Set the maximum allowable value of reactive current I qmaxset Set as reactive current protection threshold. The reactive current protection threshold is not fixed and is adjusted according to different working conditions.
[0086] Among them, the capacity of the transformer is certain. When a short circuit occurs on the secondary side, the lower the primary voltage is, the greater the primary current allowed to flow. Conversely, the higher the primary voltage is, the smaller the primary current allowed to flow.
[0087] Specifically, since the total primary current I includes two parts: reactive current and active current, and Active current I dRepresents the size of the load. The primary current of the phase-shifting transformer is composed of the superposition of multiple secondary winding currents. The heavier the load, the larger the primary current. When the phase-shifting transformer is unloaded or overloaded, the secondary winding short-circuit occurs. The primary current of the unloaded short-circuit is smaller than the primary current of the overloaded short-circuit. That is, it can be considered that the active current I d The smaller the active current I is, the smaller the total current on the primary side will be when a short circuit occurs. Correspondingly, the reactive current protection threshold should be smaller. d The larger it is, the greater the total primary current will be when a short circuit occurs, and accordingly, the greater the reactive current protection threshold should be.
[0088] Therefore, it is necessary to meet the following conditions: when the voltage effective value Erms is smaller, the maximum allowable value of reactive current I qmaxSet The larger the voltage effective value Erms, the greater the maximum allowable value of reactive current I qmaxSet The smaller the active current Id, the smaller the maximum allowable value of reactive current I qmaxSet The smaller the active current Id, the larger the maximum allowable value of reactive current I qmaxSet The bigger the I qmaxSet for:
[0089]
[0090] The third step is to set the maximum allowable value of reactive current I qmaxSet and the actual reactive current I q After comparison, the difference between the two is sent to the PI regulation controller module, and the output of the PI controller is the short-circuit current Isc.
[0091] The fourth step is to compare the short-circuit current Isc with the preset short-circuit protection current IscSet. When the short-circuit current Isc is less than the short-circuit protection current IscSet, it is determined that the secondary side of the above-mentioned phase-shifting transformer is short-circuited, and the transformer short-circuit protection flag TransFormSCFlag is set to 1; when the short-circuit current Isc is greater than or equal to the short-circuit protection current IscSet, it is determined that the secondary side of the above-mentioned phase-shifting transformer is not short-circuited, and the transformer short-circuit protection flag TransFormSCFlag is set to 0. This flag bit can be used as a tripping action signal for the upper switch of the phase-shifting transformer.
[0092] In these embodiments, when the phase-shifting transformer works normally, the reactive current I q Small, the maximum allowable value of reactive current is greater than I q At this time, the input of the PI regulation controller is always positive, the integral link accumulates until the regulator output is saturated, the maximum limit output Isc, Isc is always the maximum value, compared with the short-circuit protection current Iscset, the comparator output is 0, the transformer short-circuit protection flag TransFormSCFlag is equal to 0, indicating that no short circuit occurs at this time.
[0093] When a short circuit occurs on the secondary side, the power factor becomes low and the reactive current I q Increase, the maximum allowable value of reactive current is less than the reactive current I q , the input error of the PI regulation controller is a negative value, the regulator output gradually decreases from the maximum limiting output to the minimum limiting output, Isc gradually decreases from the maximum value, and is compared with the short-circuit protection current Iscset. The comparator output is 1, and the transformer short-circuit protection flag TransFormSCFlag is equal to 1, indicating that a short circuit has occurred.
[0094] The phase-shifting transformer secondary side short-circuit fault detection method in this embodiment collects the voltage and current on the primary side of the phase-shifting transformer, and obtains the active current, reactive current, and effective value of the power grid through coordinate transformation, and then performs calculations based on the above values, and then judges and outputs the short-circuit protection flag TransFormSCFlag based on the short-circuit protection current set by the high-voltage inverter, so as to realize timely and reliable secondary side protection action while taking into account the actual engineering application.
[0095] In a second aspect, an embodiment of the present application further provides a phase-shifting transformer secondary side short-circuit fault detection device.
[0096] In one embodiment, referring to Figure 4 The above-mentioned phase-shifting transformer secondary side short-circuit fault detection device includes a voltage and current acquisition unit and a short-circuit protection judgment unit.
[0097] The voltage and current acquisition unit is used to obtain the primary voltage and primary current of the phase-shifting transformer.
[0098] The short-circuit protection judgment unit is used to obtain the effective value of the voltage according to the primary voltage, and to obtain the active current and reactive current according to the primary current; and to obtain the maximum allowable value of the reactive current according to the effective value of the voltage and the active current.
[0099] The short-circuit protection judgment unit is also used to obtain the difference between the maximum allowable value of the reactive current and the reactive current to perform PI control and output the short-circuit current; and when the short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited.
[0100] Furthermore, in one embodiment, the short-circuit protection judgment unit includes an effective value calculation module, a coordinate transformation module, a reactive current maximum allowable value calculation module, a difference calculation module, a PI regulation controller module and a comparison judgment module.
[0101] The effective value calculation module is used to obtain the voltage effective value according to the primary voltage.
[0102] The coordinate transformation module is used to obtain active current and reactive current according to the primary current.
[0103] The reactive current maximum allowable value calculation module is used to obtain the reactive current maximum allowable value according to the voltage effective value and the active current.
[0104] The difference calculation module is used to obtain the difference between the maximum allowable value of the reactive current and the reactive current.
[0105] The PI regulation controller module is used to output the short-circuit current according to the difference.
[0106] The comparison and judgment module is used to compare the magnitude of the short-circuit current with the short-circuit protection current, and when the short-circuit current is smaller than the preset short-circuit protection current, determine that the secondary side of the phase-shifting transformer is short-circuited.
[0107] The comparison and judgment module is also used to determine that the secondary side of the phase-shifting transformer is not short-circuited when the short-circuit current is greater than or equal to a preset short-circuit protection current.
[0108] like Figure 4 As shown, further, in one embodiment, the above-mentioned phase-shifting transformer secondary side short-circuit fault detection device also includes a flag unit.
[0109] The flag unit is used to set the transformer short-circuit protection flag to 1 when the short-circuit current is less than the preset short-circuit protection current, and to set the transformer short-circuit protection flag to 0 when the short-circuit current is greater than or equal to the preset short-circuit protection current.
[0110] Among them, the functional implementation of each module in the above-mentioned phase-shifting transformer secondary side short-circuit fault detection device corresponds to the various steps in the above-mentioned phase-shifting transformer secondary side short-circuit fault detection method embodiment, and its functions and implementation processes are no longer repeated here one by one.
[0111] In a third aspect, an embodiment of the present application provides a phase-shifting transformer secondary side short-circuit fault detection device, which can be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.
[0112] Reference Figure 5 , Figure 5 The hardware structure diagram of the phase-shifting transformer secondary short-circuit fault detection device involved in the embodiment of the present application is shown in FIG. In the embodiment of the present application, the phase-shifting transformer secondary short-circuit fault detection device may include a processor, a memory, a communication interface, and a communication bus.
[0113] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.
[0114] The communication interface includes an input / output (I / O) interface, a physical interface, and a logical interface, etc., which are used to interconnect the devices inside the phase-shifting transformer secondary short-circuit fault detection device, and an interface used to interconnect the phase-shifting transformer secondary short-circuit fault detection device with other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, an optical fiber interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.
[0115] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.
[0116] The processor may be a general-purpose processor, and the general-purpose processor may call the phase-shifting transformer secondary short-circuit fault detection program stored in the memory, and execute the phase-shifting transformer secondary short-circuit fault detection method provided in the embodiment of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the phase-shifting transformer secondary short-circuit fault detection program is called may refer to the various embodiments of the phase-shifting transformer secondary short-circuit fault detection method of the present application, which will not be repeated here.
[0117] Those skilled in the art will understand that Figure 5 The hardware structure shown in the figure does not constitute a limitation on the present application, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.
[0118] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.
[0119] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.
[0120] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.
[0121] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.
[0122] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.
[0123] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.
[0124] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.
Claims
1. A method for detecting a short-circuit fault on the secondary side of a phase-shifting transformer, characterized in that: The method comprises: Obtaining the effective value of the voltage, active current and reactive current of the phase-shifting transformer; Obtaining a maximum allowable value of reactive current according to the voltage effective value and the active current; Obtaining the difference between the maximum allowable value of the reactive current and the reactive current to perform PI control and output a short-circuit current; When the short-circuit current is less than a preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited.
2. The method for detecting a secondary short-circuit fault of a phase-shifting transformer according to claim 1, characterized in that: Obtain the voltage effective value of the phase-shifting transformer, including: Obtaining the primary voltage of the phase-shifting transformer; A voltage effective value is obtained according to the primary voltage.
3. The method for detecting a secondary short-circuit fault of a phase-shifting transformer according to claim 1, wherein: Obtain the active current and reactive current of the phase-shifting transformer, including: Obtain the primary current of the phase-shifting transformer; The primary current is transformed through 3S / 2r coordinate transformation to obtain active current and reactive current.
4. The method for detecting a short-circuit fault on the secondary side of a phase-shifting transformer according to claim 1, wherein: The maximum allowable value of reactive current I qmaxset for: Where Erms is the effective value of voltage, I d is the active current, k1 is a constant, and k2 is a coefficient related to the short-circuit impedance of the phase-shifting transformer.
5. The method for detecting a secondary short-circuit fault of a phase-shifting transformer according to claim 1, wherein: When the short-circuit current is less than a preset short-circuit protection current, the method further includes: Set the transformer short-circuit protection flag position to 1; the signal with the flag position 1 is the tripping action signal of the upper switch of the phase-shifting transformer.
6. The method for detecting a short-circuit fault on the secondary side of a phase-shifting transformer according to claim 1, wherein: After the output short-circuit current, it also includes: comparing the short-circuit current with the short-circuit protection current; and, When the short-circuit current is greater than or equal to the short-circuit protection current, the transformer short-circuit protection flag is set to 0.
7. A phase-shifting transformer secondary short-circuit fault detection device, characterized in that: The device comprises: A voltage and current acquisition unit, which is used to obtain the primary voltage and primary current of the phase-shifting transformer; A short-circuit protection judgment unit, which is used to obtain a voltage effective value according to the primary voltage, obtain an active current and a reactive current according to the primary current; and obtain a maximum allowable value of the reactive current according to the voltage effective value and the active current; The short-circuit protection judgment unit is also used to obtain the difference between the maximum allowable value of the reactive current and the reactive current to perform PI control and output the short-circuit current; and when the short-circuit current is less than the preset short-circuit protection current, it is determined that the secondary side of the phase-shifting transformer is short-circuited.
8. The phase-shifting transformer secondary short-circuit fault detection device according to claim 7, characterized in that: The short circuit protection judgment unit comprises: An effective value calculation module, used for obtaining an effective value of a voltage according to the primary voltage; A coordinate transformation module, which is used to obtain active current and reactive current according to the primary current; A reactive current maximum allowable value calculation module, which is used to obtain the reactive current maximum allowable value according to the voltage effective value and the active current; A difference calculation module, used to obtain the difference between the maximum allowable value of the reactive current and the reactive current; A PI regulation controller module, which is used to output a short-circuit current according to the difference; A comparison and judgment module is used to compare the magnitudes of the short-circuit current and the short-circuit protection current, and when the short-circuit current is less than a preset short-circuit protection current, determine that the secondary side of the phase-shifting transformer is short-circuited.
9. The phase-shifting transformer secondary short-circuit fault detection device according to claim 7, characterized in that: The device also includes: The flag unit is used to set the transformer short-circuit protection flag position to 1 when the short-circuit current is less than a preset short-circuit protection current, and to set the transformer short-circuit protection flag position to 0 when the short-circuit current is greater than or equal to the preset short-circuit protection current.
10. A phase-shifting transformer secondary short-circuit fault detection device, characterized in that: The phase-shifting transformer secondary short-circuit fault detection device includes a processor, a memory, and a phase-shifting transformer secondary short-circuit fault detection program stored in the memory and executable by the processor, wherein when the phase-shifting transformer secondary short-circuit fault detection program is executed by the processor, the steps of the phase-shifting transformer secondary short-circuit fault detection method as described in any one of claims 1 to 6 are implemented.