CN110994552B - Autonomous switching method of neutral point ground current suppression device of transformer - Google Patents
Autonomous switching method of neutral point ground current suppression device of transformer Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/008—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for protective arrangements according to this subclass
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
Abstract
The invention discloses an autonomous switching method of a neutral point ground current suppression device of a transformer, which comprises a ground current direct current component suppression module, a ground current multiple harmonic suppression module, a direct current component suppression module switching switch, a multiple harmonic suppression module switching switch, a current sensor, a signal acquisition module and a switching control module; receiving current digital signals and switch state signals of all transformer neutral points in an area needing switching control; and decomposing the current digital signal to obtain a direct current component and multiple harmonic components, comparing the direct current component and the multiple harmonic components with corresponding preset thresholds respectively, solving the scheme with the least input number of the ground current direct current component suppression module and the ground current multiple harmonic suppression module which achieve the ground current suppression effect when the ground current components are over-high if the thresholds are exceeded, and achieving the ground current suppression. The invention can effectively carry out integral suppression on the ground current of the neutral point of the transformer in the region and improve the stability of the power system.
Description
Technical Field
The invention belongs to the technical field of safe operation of power systems, and particularly relates to an autonomous switching method of a neutral point ground current suppression device of a transformer.
Background
Since the twenty-first century, with the rapid improvement of economic strength of China, rail transit with the characteristics of safety, stability, high efficiency and the like is used as a novel transportation tool and is rapidly developed in large and medium-sized cities of China. By the end of 2018, 35 cities in China are built into 5766.6 km. Dense track traffic can generate stray currents with varying frequency and containing both dc and ac components during operation. At present, a multi-pulse rectifier set is mainly adopted by rail transit as a traction power supply system of the rail transit, and the multi-pulse rectifier set can generate 6-order, 12-order, 24-order and other 6-frequency multiplication and 12-frequency multiplication subharmonics due to the fact that winding structures are different due to the fact that the multi-pulse rectifier set is limited by a transformer manufacturing process according to field measurement data. For multi-pulse rectification, the content of the generated single harmonic is generally inversely related to the harmonic order. Therefore, harmonics generated by rail traffic are usually dominated by harmonics of order 6 and 12. Because the rail used for backflow in rail transit is in a poor insulation state, the ground and the rail form a parallel backflow path, stray current leaks to the ground from the rail to form ground current, and the ground current invades a power grid system through a neutral point of an alternating current transformer of a transformer substation. The long-term frequent invasion of the ground current can cause serious conditions of serious direct current magnetic biasing, vibration and noise increase, reactive loss increase, voltage waveform distortion, relay protection fault and the like of the alternating current transformer, and great threats are brought to the safe and stable operation of power grid equipment and a system.
The main measures currently used for suppressing the direct current component of the earth current invading the neutral point of the alternating-current transformer are roughly classified into five categories. The first is a neutral point series capacitance method; the second type is a neutral point series resistance method; the third type is a reverse injection current method; the fourth type is an alternating current circuit series capacitance method; the fifth type is a method for changing the internal structure of the alternating current transformer. The first type neutral point series capacitance method has low cost and can effectively inhibit direct current components in the ground current, so the method is widely applied. For the alternating current component in the earth current, no mature inhibition method exists in the market at present. Meanwhile, because relatively complex electrical connection exists between the alternating-current transformers of the transformer substation, and a ground current suppression device is installed at the neutral point of one transformer, although the ground current invading the neutral point of the transformer can be effectively suppressed, the invasion situation of the ground current of the neutral points of other transformers is aggravated. Meanwhile, the input of the ground current suppression device changes a circuit structure, and a large amount of input can bring certain influence on the setting of relay protection. Therefore, how to effectively suppress the ground current of the transformer with serious ground current intrusion without increasing the ground current intrusion of the neutral point of other transformers is a problem to be solved at present.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an automatic switching method of a neutral point ground current suppression device of a transformer, aiming at suppressing the ground current of the transformer with large neutral point ground current intrusion by a minimum ground current suppression device under the condition of not aggravating the ground current intrusion of other transformer neutral points.
In order to achieve the purpose, the invention provides an autonomous switching method of a neutral point ground current suppression device of a transformer, which comprises the following steps:
receiving current digital signals and switch state signals of all transformer neutral points in an area needing switching control;
and decomposing the current digital signal to obtain a direct current component and multiple harmonic components, comparing the direct current component and the multiple harmonic components with corresponding preset thresholds respectively, solving the scheme with the least input number of the ground current direct current component suppression module and the ground current multiple harmonic suppression module which achieve the ground current suppression effect when the ground current components are over-high if the thresholds are exceeded, and achieving the ground current suppression.
Preferably, if the ground current component is not too large, the currently received switch state signal is not updated; and if the ground current component is overlarge, updating the currently received switch state signal, and sending the switch state signal corresponding to the scheme with the least investment of the ground current direct current component suppression module and the ground current multiple harmonic suppression module which achieve the ground current suppression effect.
Preferably, in the process of updating the switching state signal, the solved model parameter is updated to the state same as the actual working condition by using the received switching state signal, the decomposed direct-current component and the multiple harmonic component.
Preferably, after the solution model parameters are updated, the switch state signals are used as independent variables, the number of the input ground current direct current component suppression modules and the number of the ground current multiple harmonic suppression modules are used as target functions, whether the direct current components and the multiple harmonic components exceed corresponding preset thresholds is used as constraint conditions, and the genetic algorithm is used for optimizing.
Preferably, the transformer neutral point ground current suppression device comprises a ground current direct current component suppression module, a ground current multiple harmonic suppression module, a direct current component suppression module switching switch, a multiple harmonic suppression module switching switch, a current sensor, a signal acquisition module and a switching control module; the ground direct current component suppression module is connected with a direct current component suppression module switching switch in parallel, the ground current multiple harmonic suppression module is connected with the multiple harmonic suppression module switching switch in parallel and then connected in series in a transformer neutral line, a current sensor is connected in series in the transformer neutral line, a signal acquisition module receives signals acquired by the current sensor and switch state signals transmitted by each switching switch and transmits the switch state signals, and a switching control module receives current sampling signals and the switch state signals of the signal acquisition module and transmits the switch state signals.
Preferably, the ground current multiple harmonic suppression module comprises a first inductor, a first capacitor and a first bypass protection unit, the first inductor and the first capacitor are connected in parallel to form a band elimination filter for filtering multiple harmonic components in the ground current, the first bypass protection unit is connected in parallel with the first inductor and the first capacitor, and the first bypass protection unit is timely put into use when an overvoltage condition occurs, so that the safe operation of the ground current multiple harmonic suppression module is ensured.
Preferably, the ground current direct current component suppression module comprises a second capacitor and a second bypass protection unit, the second capacitor is used for suppressing direct current components in the ground current, and the second bypass protection unit is connected with the second capacitor in parallel and timely input when an overvoltage condition occurs, so that safe operation of the ground current direct current component suppression module is guaranteed.
Preferably, the signal acquisition module comprises a switching value input circuit, a current input circuit, a first electrical isolation circuit, a second electrical isolation circuit, a filter circuit, an AD sampling circuit, a switching value output circuit and a first communication unit; the switching value input circuit receives switching state signals of a multiple harmonic suppression module switching switch and a direct current component suppression module switching switch; the second electrical isolation circuit is connected between the first communication unit and the switching value input circuit and used for carrying out photoelectric isolation on the switching state signal; the current input circuit receives neutral point current data acquired by the current sensor; the filter circuit receives a current signal transmitted by the current input circuit and filters a high-frequency noise signal; the AD sampling circuit receives a current signal transmitted by the filter circuit, and converts the signal into a digital quantity through sampling, holding, quantizing and encoding operations; the first communication unit receives digital signals transmitted by the AD sampling circuit and switch state signals transmitted by the second electrical isolation circuit, transmits the signals to the switching control module, and receives the switch state signals transmitted by the switching control module after the switching control module transmits an optimal device switching scheme back; the first electrical isolation circuit is connected between the first communication unit and the switching value output circuit and used for carrying out photoelectric isolation on the switching state signal; the switching value output circuit receives the switching state signals transmitted by the first electrical isolation circuit and transmits the switching state signals to the multiple harmonic suppression module switching switch and the direct current component suppression module switching switch.
Preferably, the switching control module comprises a second communication unit, an electrical quantity monitoring unit and a main controller, the second communication unit receives the current digital signal and the switching state signal transmitted by the signal acquisition module and transmits the current digital signal and the switching state signal to the main controller and the electrical quantity monitoring unit, and after the main controller obtains an optimal device switching scheme, the switching control module receives the switching state signal transmitted by the main controller and transmits the switching state signal to the signal acquisition module; the electric quantity monitoring unit receives a current digital signal and a switch state signal transmitted by the second communication unit, and a current direct current component and a multiple harmonic component transmitted by the main controller, and stores and displays the signals; the main controller receives the current digital signal and the switch state signal transmitted by the second communication unit, performs FFT decomposition on the current signal to obtain a direct current component and a multiple harmonic component, and transmits the current component to the electric quantity monitoring unit.
The number of the multiple harmonic suppression modules is multiple, the multiple harmonic suppression modules correspond to multiple harmonics, and the multiple harmonics are 6-frequency multiplication subharmonics and 12-frequency multiplication subharmonics.
Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:
(1) aiming at the defect that the conventional neutral point ground current blocking device can only inhibit the direct current component of the ground current, the autonomous switching method of the transformer neutral point ground current inhibiting device provided by the invention adopts a multistage series passive filter structure, utilizes the parallel connection of an inductor and a capacitor to form a band elimination filter, autonomously selects the switching of a multiple harmonic wave inhibiting module, and can effectively inhibit the 6 th harmonic wave, the 12 th harmonic wave and the like which account for the high proportion in the harmonic wave component of the ground current.
(2) The optimal ground current suppression device switching scheme automatically searched through the genetic algorithm can effectively suppress the ground current under the condition of least ground current suppression devices. The change of the circuit structure is reduced as much as possible, the influence on the relay protection is reduced,
(3) the electric quantity monitoring unit can display and store the neutral point ground current of the transformer, the direct current component and the harmonic component of the neutral point ground current in real time, and provides more comprehensive data for monitoring the running state of the transformer by operators.
(4) The bypass protection unit can bypass in time when the ground current suppression device has an overvoltage condition, so that the reliability of the device is improved.
Drawings
Fig. 1 is a schematic structural diagram of a neutral point ground current suppression device of a transformer provided by the invention;
fig. 2 is a schematic flow chart of an autonomous switching method of the neutral point ground current suppression device of the transformer according to the present invention;
fig. 3 is an operation flow chart of the autonomous switching of the neutral point ground current suppression device of the transformer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
An embodiment of the present invention provides a transformer neutral point ground current suppression device, as shown in fig. 1, including: the device comprises a ground current 6-order harmonic suppression module, a 6-order harmonic suppression module switching switch, a ground current 12-order harmonic suppression module, a 12-order harmonic suppression module switching switch, a ground current direct-current component suppression module, a direct-current component suppression module switching switch, a current sensor, a signal acquisition module and a switching control module. The ground current 6-order harmonic suppression module is connected with the 6-order harmonic suppression module switching switch in parallel; the ground current 12-order harmonic suppression module is connected with the 12-order harmonic suppression module switching switch in parallel; the ground direct current component suppression module is connected with the direct current component suppression module switching switch in parallel. The three parts are connected in series in a neutral line of the transformer. The current sensor is connected in series with a neutral line of the transformer; the signal acquisition module receives the acquisition signal of the current sensor and the switching state signal transmitted by the switching switch of each module, and transmits the switching state signal; the switching control module receives the current sampling signal and the switch state signal of the signal acquisition module and issues the switch state signal.
Specifically, the ground current 6 th harmonic suppression module includes: inductor L1Capacitor C1And a bypass protection unit 1. Inductor L1And a capacitor C1The band elimination filters are formed by parallel connection and filter 6 th harmonic components in the ground current; bypass protection unit 1 and inductor L1Capacitor C1Parallel connection, timely input when overvoltage occurs, bypass inductance L1Capacitor C1And the safe operation of the ground current 6-order harmonic suppression module is ensured.
Specifically, the ground current 12 th harmonic suppression module includes: inductor L2Capacitor C2And a bypass protection unit 2. Inductor L2And a capacitor C2The band elimination filters are formed by parallel connection and are used for filtering 12 th harmonic components in the ground current; bypass protection unit 2 and inductor L2Capacitor C2Parallel connection, timely input when overvoltage occurs, bypass inductance L2Capacitor C2And the safe operation of the ground current 12 th harmonic suppression module is ensured.
Specifically, the ground direct current component suppression module includes: capacitor C3And a bypass protection unit 3. Capacitor C3The DC component in the ground current is suppressed by utilizing the DC blocking characteristic of the capacitor; bypass protection unit 3 and capacitor C3Parallel connection, timely input when overvoltage occurs, bypass capacitor C3And the safe operation of the ground direct current component suppression module is ensured.
Specifically, the signal acquisition module includes: the device comprises a switching value input circuit, an electrical isolation circuit 2, a current input circuit, a filter circuit, an AD sampling circuit, a communication unit 1, an electrical isolation circuit 1 and a switching value output circuit. The switching value input circuit receives state signals of a 6 th harmonic suppression module switching switch, a 12 th harmonic suppression module switching switch and a direct current component suppression module switching switch; the electric isolation circuit 2 is connected between the communication unit 1 and the switching value input circuit and is used for carrying out photoelectric isolation on the switching state signal; the current input circuit receives neutral point current data acquired by the current sensor; the filter circuit receives a current signal transmitted by the current input circuit and filters a high-frequency noise signal; the AD sampling circuit receives a current signal transmitted by the filter circuit, and converts the signal into a digital quantity through sampling, holding, quantizing and encoding operations; the communication unit 1 receives digital signals transmitted by the AD sampling circuit, receives switch state signals transmitted by the electrical isolation circuit 2, and transmits the signals to the switching control module. After the switching control module returns the optimal device switching scheme, receiving a switching state signal transmitted by the switching control module; the electric isolation circuit 1 is connected between the communication unit 1 and the switching value output circuit and used for carrying out photoelectric isolation on the switching state signal; the switching value output circuit receives the switching state signal transmitted by the electrical isolation circuit 1 and transmits the switching state signal to the 6 th harmonic suppression module switching switch, the 12 th harmonic suppression module switching switch and the direct current component suppression module switching switch.
Specifically, the switching control module includes: communication unit 2, electric quantity monitoring unit and main control unit. The communication unit 2 receives the current digital signals and the switch state signals transmitted by all the signal acquisition modules, and transmits the current digital signals and the switch state signals to the main controller and the electric quantity monitoring unit. After the main controller simulates to obtain an optimal device switching scheme, receiving a switching state signal transmitted by the main controller, and transmitting the switching state signal to each signal acquisition module; the electric quantity monitoring unit receives a current digital signal and a switch state signal transmitted by the communication unit 2, and a current direct current component, a 6 th harmonic component and a 12 th harmonic component transmitted by the main controller, and stores and displays the signals; the main controller receives the current digital signal and the switch state signal transmitted by the communication unit 2, performs FFT decomposition on the current signal to obtain a direct current component, a 6 th harmonic component and a 12 th harmonic component, and transmits the current components to the electric quantity monitoring unit. And updating the simulation model parameters by using the current components and the switching values. And (3) performing simulation solution on the model with the updated parameters, seeking a scheme with least investment of multiple harmonic suppression modules achieving the ground current suppression effect by adopting a genetic algorithm, and transmitting a switch state signal corresponding to the scheme into the communication unit 2.
It should be noted that the transformer neutral point ground current suppression device in the above embodiment is only a basic structure, and is intended to effectively suppress 6 th and 12 th harmonics, which account for a high proportion of the harmonic components of the ground current. For the region with higher requirement on the distortion rate of a certain harmonic or the whole harmonic in the ground current, a ground current multiple harmonic suppression module corresponding to the harmonic times can be added into the basic structure to achieve the effect of harmonic suppression. Meanwhile, multiple harmonic suppression modules adopting the band elimination filter structure twice can be replaced by a double-tuned filter structure, the structure of the device is simplified, and the operation reliability of the system is improved.
Fig. 2 is a flow chart of seeking an optimal switching scheme of the suppression device by using a genetic algorithm. When the current of any transformer neutral point in the region exceeds the corresponding limit value I by 6 th harmonic component, 12 th harmonic component or direct current componentlim6、Ilim12Or IlimdcIn time, a genetic algorithm and simulation calculation are required to find an optimal suppression device switching scheme. Since the switch state only has two states of closing and opening, the state corresponds to the withdrawing and putting state of the ground current suppression device. Therefore, for the ith transformer in all the n transformers in the area, the ground current 6 th harmonic suppression module switches the state xi1Switching state x of ground current 12 th harmonic suppression modulei2Ground direct current component suppression module switching state xi3The following encoding operations are performed:
in order to change the circuit structure as little as possible and reduce the influence on relay protection, the optimal device switching scheme is the scheme with the least number of ground current suppression devices. Thus, the fitness function J has the following form:
when a certain current component of a certain transformer in the region exceeds a limit value, the switching scheme of the ground current suppression device needs to be adjusted to suppress the current component exceeding the limit value. In order to ensure that the condition of ground current invaded by the neutral points of other transformers is not aggravated when the neutral points of the transformers are thrown into the ground current suppression device, the switching scheme of the optimal suppression device ensures that the ground current of the neutral points of all the transformers in the area has 6-th harmonic component Ii112 th harmonic component Ii2And a direct current component Ii3Are all within corresponding limits. Therefore, there are the following boundary conditions:
as shown in fig. 3, the autonomous switching of the neutral point ground current suppression device of the transformer disclosed by the present invention includes the following processes:
step 1: the current sensor connected in series with the neutral point of the transformer collects a neutral point current signal and transmits the neutral point current signal to the current input circuit in the signal collection module. Meanwhile, a switching value input circuit in the signal acquisition module receives switching state signals of a switching switch of the 6 th harmonic suppression module, a switching switch of the 12 th harmonic suppression module and a switching switch of the direct-current component suppression module.
Step 2: the received current signal is low-pass filtered by the filter circuit to filter out high-frequency noise signals in the signal, and then the current signal is converted into a digital signal by the AD sampling circuit through sampling, holding, quantizing and encoding operations. Meanwhile, the received switch state signal is subjected to photoelectric isolation through the electric isolation circuit 2, and the current signal and the switch state signal are transmitted to the communication unit 1 together.
And step 3: and the communication units 2 in the switching control module receive current signals and switch state signals transmitted by the communication units 1 in all the n signal acquisition modules in the area.
And 4, step 4: and a main controller in the switching control module performs FFT decomposition on the received current signal to obtain a direct current component, a 6 th harmonic component and a 12 th harmonic component in the ground current. The electric quantity monitoring unit receives the switch state signal, the current signal and the direct current component, 6 th harmonic component and 12 th harmonic component signals of the current, and stores and displays the signals.
And 5: the main controller in the switching control module calculates and decomposes the 6 th harmonic component, the 12 th harmonic component and the direct current component in the obtained ground current and the corresponding limit value Ilim6、Ilim12And IlimdcA comparison is made. If the current component exceeding the limit value does not exist, updating the switch state signal required to be sent to the signal acquisition module according to the received current switch state signal; and if the current component exceeding the limit value exists, updating the parameters of the ground current distribution calculation model in the main controller by using the switch state signal and the direct current component, the 6 th harmonic component and the 12 th harmonic component of the ground current.
Step 6: and a main controller in the switching control module seeks an optimal suppression device switching scheme by utilizing a genetic algorithm. The specific operation is as follows:
(1) the main controller encodes the switching state of each device, namely a switching state signal, and each switching scheme is encoded into a chromosome individual x in a genetic algorithm11，…，xn1，x12，…，xn2，x13，…，xn3。
(2) And randomly generating a plurality of switching schemes to form a population.
(3) And inputting the switch states corresponding to each chromosome individual into the ground current distribution calculation model after updating the parameters, calculating the ground current direct current component, the 6 th harmonic component and the 12 th harmonic component corresponding to the switching scheme, and judging whether the boundary conditions are met.
(4) And calculating a fitness function J for the switching schemes meeting the boundary conditions, and storing the switching scheme with the maximum fitness function.
(5) And judging whether the calculation result meets an end condition, namely reaching the upper limit of the calculation iteration times or finding an optimal scheme. If the end condition is met, outputting an optimal device switching scheme; if the end conditions are not met, the chromosome individuals in the population are selected by using a roulette selection method, then are crossed by using a single-point crossing method, and then are mutated by using a binary mutation method. And (5) repeating the operations (3) to (5) until the ending condition is met, and updating the switching signals according to the calculated optimal device switching scheme.
And 7: and the updated switch signals are transmitted to the signal acquisition modules, and the signal acquisition modules transmit the switch state signals to the corresponding device switching switches to drive the switches to act, so that the effect of inhibiting the ground current is achieved.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. An autonomous switching method of a neutral point ground current suppression device of a transformer is characterized by comprising the following steps:
receiving current digital signals of all transformer neutral points in an area needing switching control;
performing FFT decomposition on the current digital signal to obtain a direct current component and multiple harmonic components, comparing the direct current component and the multiple harmonic components with corresponding preset thresholds respectively, solving a scheme with the least input number of a ground current direct current component suppression module and a ground current multiple harmonic suppression module which achieve the ground current suppression effect when the ground current component is overlarge if the thresholds are exceeded, and achieving the ground current suppression;
receiving switch state signals of all transformer neutral points in an area needing switching control, and if the ground current component is not too large, not updating the currently received switch state signals; if the ground current component is too large, updating the currently received switch state signal, and sending a switch state signal corresponding to a scheme with least input of a ground current direct current component suppression module and a ground current multiple harmonic suppression module which achieve the ground current suppression effect; in the process of updating the switching state signal, updating the solving model parameter to the state same as the actual working condition by using the received switching state signal, the direct current component obtained by decomposition and the multiple harmonic component; and after updating the solving model parameters, optimizing by using a genetic algorithm by taking the switch state signal as an independent variable, taking the number of the input ground current direct current component suppression modules and the number of the ground current multiple harmonic suppression modules as an objective function and taking whether the direct current component and the multiple harmonic component exceed corresponding preset thresholds as constraint conditions.
2. The autonomous switching method of the transformer neutral point ground current suppression device according to claim 1, wherein the transformer neutral point ground current suppression device comprises a ground current direct current component suppression module, a ground current multiple harmonic suppression module, a direct current component suppression module switching switch, a multiple harmonic suppression module switching switch, a current sensor, a signal acquisition module and a switching control module; the ground current direct current component suppression module is connected with a direct current component suppression module switching switch in parallel, the ground current multiple harmonic suppression module is connected with the multiple harmonic suppression module switching switch in parallel and then connected in series in a transformer neutral line, the current sensor is connected in series in the transformer neutral line, the signal acquisition module receives signals acquired by the current sensor and switch state signals transmitted by the switching switches and transmits the switch state signals, and the switching control module receives current sampling signals and switch state signals of the signal acquisition module and transmits the switch state signals.
3. The automatic switching method of the transformer neutral point ground current suppression device according to claim 2, wherein the ground current multiple harmonic suppression module comprises a first inductor, a first capacitor and a first bypass protection unit, the first inductor and the first capacitor are connected in parallel to form a band elimination filter for filtering multiple harmonic components in the ground current, and the first bypass protection unit is connected in parallel with the first inductor and the first capacitor and is timely switched on when an overvoltage condition occurs, so that safe operation of the ground current multiple harmonic suppression module is ensured.
4. The automatic switching method of the neutral point ground current suppression device of the transformer according to claim 2, wherein the ground current direct current component suppression module comprises a second capacitor and a second bypass protection unit, the second capacitor is used for suppressing direct current components in ground current, and the second bypass protection unit is connected in parallel with the second capacitor and is timely switched in when an overvoltage condition occurs, so that safe operation of the ground current direct current component suppression module is ensured.
5. The automatic switching method of the transformer neutral point ground current suppression device according to claim 2, wherein the signal acquisition module comprises a switching value input circuit, a current input circuit, a first electrical isolation circuit, a second electrical isolation circuit, a filter circuit, an AD sampling circuit, a switching value output circuit and a first communication unit; the switching value input circuit receives switching state signals of a multiple harmonic suppression module switching switch and a direct current component suppression module switching switch; the second electrical isolation circuit is connected between the first communication unit and the switching value input circuit and is used for carrying out photoelectric isolation on the switching state signal; the current input circuit receives neutral point current data acquired by the current sensor; the filter circuit receives a current signal transmitted by the current input circuit and filters a high-frequency noise signal; the AD sampling circuit receives a current signal transmitted by the filter circuit and converts the signal into a digital quantity through sampling, holding, quantizing and encoding operations; the first communication unit receives digital signals transmitted by the AD sampling circuit and on-off state signals transmitted by the second electrical isolation circuit, transmits the signals to the switching control module, and receives the on-off state signals transmitted by the switching control module after the switching control module transmits an optimal device switching scheme back; the first electrical isolation circuit is connected between the first communication unit and the switching value output circuit and used for carrying out photoelectric isolation on the switching state signal; and the switching value output circuit receives the switching state signal transmitted by the first electrical isolation circuit and transmits the switching state signal to the multiple harmonic suppression module switching switch and the direct current component suppression module switching switch.
6. The automatic switching method of the transformer neutral point ground current suppression device according to claim 2, wherein the switching control module comprises a second communication unit, an electrical quantity monitoring unit and a main controller, the second communication unit receives a current digital signal and a switching state signal transmitted by the signal acquisition module and transmits the current digital signal and the switching state signal to the main controller and the electrical quantity monitoring unit, and after the main controller obtains an optimal device switching scheme, the main controller receives the switching state signal transmitted by the main controller and transmits the switching state signal to the signal acquisition module; the electric quantity monitoring unit receives a current digital signal and a switch state signal transmitted by the second communication unit, and a current direct current component and a multiple harmonic component transmitted by the main controller, and stores and displays the signals; the main controller receives the current digital signal and the switch state signal transmitted by the second communication unit, performs FFT decomposition on the current signal to obtain a direct current component and a multiple harmonic component, and transmits the current component to the electric quantity monitoring unit.
7. The automatic switching method of the transformer neutral point ground current suppression device according to claim 2, wherein the number of the multiple harmonic suppression modules is multiple, and the multiple harmonic suppression modules correspond to multiple harmonics, and the multiple harmonics are 6-fold harmonics and 12-fold harmonics.
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| CN113408093B (en) * | 2021-06-29 | 2022-04-29 | 西南交通大学 | Capacitive blocking device configuration optimization method based on genetic algorithm |
| CN116203309B (en) * | 2022-11-18 | 2023-12-12 | 南方电网数字电网研究院有限公司 | Fluxgate excitation signal processing method, device, server and storage medium |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280809A (en) * | 2013-06-14 | 2013-09-04 | 徐州中矿大传动与自动化有限公司 | Active power filter suitable for multi-working-condition compensation and switching and switching method thereof |
| US20170213642A1 (en) * | 2016-01-11 | 2017-07-27 | New York University | Earth surface potential and harmonic mitigating transformers |
| US20170227592A1 (en) * | 2015-04-29 | 2017-08-10 | ZTZ Service International, Inc. | Combined On-Line Bushing Monitoring and Geo-Magnetic Induced Current Monitoring System |
| CN107046288A (en) * | 2017-05-02 | 2017-08-15 | 广东工业大学 | A kind of structure and its control method of mixed harmonic suppressor |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8878396B2 (en) * | 2010-07-20 | 2014-11-04 | Emprimus, Llc | Continuous uninterruptable AC grounding system for power system protection |
| US8537508B2 (en) * | 2010-07-20 | 2013-09-17 | Emprimus, Llc | Sensing and control electronics for a power grid protection system |
| CN103094903B (en) * | 2013-01-30 | 2015-10-21 | 株洲变流技术国家工程研究中心有限公司 | A kind of car net resonance floor synthetic governing system |
| CN105490249B (en) * | 2016-01-18 | 2018-03-23 | 阳江核电有限公司 | Linked protector and method for transformer neutral point blocking device |
| CN107147095B (en) * | 2017-05-25 | 2019-06-28 | 华中科技大学 | A kind of device for inhibiting direct current and spuious harmonic current to enter transformer neutral point |
| CN107332211B (en) * | 2017-06-28 | 2019-01-25 | 大连理工大学 | A kind of capacitance-resistance type transformer DC magnetic bias inhibition device |
| KR20190019764A (en) * | 2017-08-18 | 2019-02-27 | 한국전력공사 | Neutral ground reactor for preventing harmonics and manufacture method thereof |
| CN109103861A (en) * | 2018-08-13 | 2018-12-28 | 广州供电局有限公司 | Inhibit the device of AC transformer neutral point direct current and alternating current |
-
2019
- 2019-12-05 CN CN201911233871.7A patent/CN110994552B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280809A (en) * | 2013-06-14 | 2013-09-04 | 徐州中矿大传动与自动化有限公司 | Active power filter suitable for multi-working-condition compensation and switching and switching method thereof |
| US20170227592A1 (en) * | 2015-04-29 | 2017-08-10 | ZTZ Service International, Inc. | Combined On-Line Bushing Monitoring and Geo-Magnetic Induced Current Monitoring System |
| US20170213642A1 (en) * | 2016-01-11 | 2017-07-27 | New York University | Earth surface potential and harmonic mitigating transformers |
| CN107046288A (en) * | 2017-05-02 | 2017-08-15 | 广东工业大学 | A kind of structure and its control method of mixed harmonic suppressor |
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