472 results about "Tap changer" patented technology

The invention discloses an on-load tap-changer vibration fault diagnosis algorithm based on tensor feature and adaptive weighted Stacking integration, relates to the technical field of on-load tap-changer fault diagnosis, and is used for improving the fault diagnosis precision. Comprising the following steps: S1, data acquisition; s2, feature extraction; the method comprises the following steps: extracting multi-scale time-frequency characteristics of an on-load tap-changer vibration signal by using wavelet scattering transform WST, and realizing low-rank decomposition and dimensionality reduction characterization of high-dimensional characteristics by combining a non-negative tensor decomposition model NTF; s3, fault diagnosis; a multi-base learner Stacking integration framework is adopted, and a prediction matrix is generated through K-fold cross validation; through a swarm intelligent optimization algorithm SRA, hyper-parameters and fusion weights of all base learners are adjusted, L2 regularization suppression over-fitting is introduced, and finally fault classification is realized by adopting a logic regression element learner with Softmax cross entropy. According to the invention, through fault diagnosis of multi-model adaptive fusion and optimization, the fault identification precision, stability and on-line monitoring capability are improved.

The invention discloses a multidimensional monitoring system of an on-load tap-changer for a converter transformer and a fault prediction method, the system comprises a motor, a change-over switch core and other parts, and a data acquisition module is provided with a current, vibration and oil chromatography acquisition unit and a vacuum tube life monitoring unit. The current sensor collects motor current, the vibration sensor collects vibration signals of the change-over switch, the oil chromatography collection unit analyzes an oil sample, and the vacuum tube life monitoring unit evaluates the residual life of the vacuum tube. And a data transmission and processing analysis module. The fault prediction method comprises the steps of data acquisition, preprocessing, multi-dimensional data fusion, fault prediction model construction, feature extraction and selection, fault prediction and evaluation and the like. And screening characteristic parameters and fusion data by adopting a plurality of technical means, and constructing a machine learning model to predict faults. According to the invention, multi-source data acquisition and multiple analysis methods are integrated, the equipment state can be comprehensively reflected, the monitoring reliability is improved, faults can be predicted in advance, and the equipment fault rate is reduced.

The invention discloses an on-load tap-changer oil dissolved gas monitoring device which comprises a variable capacity container, a two-way electromagnetic valve, a switching mechanism, a chromatographic column system, a high-sensitivity detector and a low-sensitivity detector which are sequentially connected, and the top and the bottom of the variable capacity container are connected through a circulating pump to form a gas flow loop. The variable-capacity container is connected with the on-load tap-changer through a connecting pipe, the switching mechanism is connected with at least two quantitative pipes with different capacities, and the switching mechanism is used for equally transferring gas in the variable-capacity container to the quantitative pipes and then sequentially transferring the gas in the quantitative pipes to the chromatographic column system. The invention further discloses a method for monitoring the dissolved gas in the on-load tap-changer oil. According to the monitoring device and the monitoring method for the dissolved gas in the oil of the on-load tap-changer, the detection range of the concentration is improved, a concentration blind area which is not detected and misjudgment of signal saturation can be avoided, and the detection accuracy is improved.

A method of generating a timing control signal for controlling the timing of a change of a transformer tap of a transformer is provided. The transformer includes an on-load tap changer including plural respective transformer taps. The method includes monitoring a voltage on a primary side and / or on a secondary side of the transformer to obtain a monitoring signal and deriving, from the monitoring signal, an intermediate signal that is indicative of at least one zero crossing of a tap voltage at the transformer tap. Deriving the intermediate signal includes estimating, based on the monitoring signal, a phase of the monitored voltage to obtain a phase signal and applying to the phase signal a phase correction for a phase shift between the monitoring signal or a signal derived therefrom and the tap voltage at the transformer tap. The timing control signal is derived from the intermediate signal.

The embodiment of the invention discloses a fault diagnosis method of an on-load tap-changer and related equipment, which dynamically optimizes a feature matrix by using a channel-level descriptor and an inter-channel covariance regularization term, enhances the independence and discrimination capability of features, reduces the loss of effective features, and improves the fault diagnosis efficiency. The loss function can optimize the characterization of the potential features and the clustering effect of the feature channel, and the similarity matrix after optimization of the loss function is used for carrying out the dimension reduction operation, thereby achieving the precise output of the low-dimensional feature vector, and enabling the on-load tap-changer fault diagnosis result outputted by the fault diagnosis module to be more precise.

The invention provides a variable-step-size on-load tap changer, a control method, a control system, equipment and a medium. The variable-step-size on-load tap changer comprises at least one static contact unit, two moving contact mechanisms and a control device, wherein the two moving contact mechanisms independently slide on the static contact unit; the control device is connected with the two moving contact mechanisms; the static contact unit comprises three static contacts, and all the static contacts are arranged in an annular array. Each moving contact mechanism realizes uninterruptible conductive connection switching with each static contact in the sliding process; by means of the characteristics that the number of the static contacts is matched with that of the moving contact mechanisms, the moving contact mechanisms move independently, and all the static contacts are arranged in an annular array, the two moving contact mechanisms can slide to the static contact of any potential in one-step action, the static contacts of multiple potentials are combined and connected pairwise, seven voltage adjusting gears are formed, and the voltage adjusting efficiency is improved. Therefore, one-step switching between variable-step voltage regulation and any voltage regulation gear is realized, and cross-gear quick regulation is realized.

The invention discloses an OLTC topological structure of an electronic soft switching technology and a driving method. In the topological structure, a power supply is connected with a first transformer, the first transformer is connected with a second transformer, and the second transformer is connected with a load; a low-voltage winding of the first transformer is connected with a plurality of taps; the fixed end of the low-voltage winding of the first transformer and each tap are connected with one end of an independent mechanical switch; according to an interval connection mode, the other ends of all the mechanical switches are connected to form two series switch loops, and each series switch loop is connected with an independent electronic change-over switch to form two series circuits; the two electronic change-over switches are connected in parallel, and the second transformer is connected into a series circuit controlled by the two electronic change-over switches respectively. The mechanical switch and the electronic change-over switch are jointly used, so that short-circuit current and surge voltage cannot be generated when the electronic change-over switch performs state switching, and the quality of output voltage waveforms is improved.

The invention discloses a strip-shaped off-circuit tap-changer device which comprises a supporting structure, three phases of static contact assemblies are arranged on the supporting structure, and each phase of static contact assembly is provided with a moving contact assembly. A rack capable of sliding back and forth is arranged in the supporting structure; the moving contact assembly is installed on the rack and can move back and forth along with the rack. A transmission shaft is rotationally mounted on the supporting structure; a gear meshed with the rack is coaxially fixed on the transmission shaft; the gear shifting limiting and locking mechanism comprises a gear indicating board, a handle and a limiting piece. The gear indication board is fixedly arranged on the transformer and arranged outside the transmission shaft in a sleeving mode. A plurality of positioning holes are formed in the gear indication board; the handle is positioned above the gear indication board and is fixed on the transmission shaft; the limiting piece is in threaded connection with the handle, and after the limiting piece is aligned with the positioning hole, the limiting piece spirally moves downwards and is inserted into the positioning hole. The device is simple in structure, stable and reliable in performance, low in manufacturing cost, investment-saving and good in anti-corrosion and moisture-proof performance.

The invention relates to the technical field of transformers, in particular to a transformer on-load tap changer and a voltage regulation control method. The method comprises the following steps: acquiring a high-voltage side voltage, a low-voltage side voltage and a low-voltage side current; acquiring low-voltage fluctuation and low-current fluctuation according to the fluctuation difference between the low-voltage side voltage and the low-voltage side current in the historical data; comparing the volatility before the starting moment to determine a fluctuation time period; on-load voltage difference is obtained based on the correlation between the high-voltage side voltage and the low-voltage side voltage of the first half section of the fluctuation time period in the historical data and the difference between the current moment voltage and the historical moment voltage; obtaining the critical risk of the on-load voltage based on the offset and the difference of the on-load voltage; the switching taps are adjusted based on a comparison of the on-load voltage critical risk to a risk threshold. According to the invention, the voltage regulation response speed, the voltage regulation precision and the overall stability of power grid operation are improved.

The invention discloses an on-load tap-changer fault diagnosis method based on TVFEMD noise reduction-chaotic feature fusion-NGBoost, relates to the technical field of on-load tap-changer fault diagnosis, and is used for solving the problems that complex vibration signals are difficult to effectively analyze and single feature diagnosis precision is insufficient. Self-adaptive positioning of a vibration signal at the action moment of a change-over switch is realized by adopting a short-time energy-entropy ratio algorithm; signal noise reduction is carried out on the vibration signal by utilizing time-varying filtering empirical mode decomposition TVFEMD; feature extraction is carried out based on chaotic characteristics; delay time is determined through a mutual information method; and inputting the vibration signal into an NGBoost multi-classification fault diagnosis model for type identification. According to the method, the problems of instability, nonlinearity and high noise of OLTC vibration signals can be effectively solved, feature extraction is stable and reliable, and the fault diagnosis accuracy is high.

The invention discloses a hybrid distributed power flow controller topological structure and a control method thereof. The topological structure comprises a distribution network Sen transformer DST and a distributed static synchronous series compensator DSSC. The distribution network Sen transformer DST comprises a three-phase double-winding transformer and an on-load tap changer group; each phase of the three-phase double-winding transformer comprises a main winding and a secondary winding, the high-voltage end of the three-phase main winding is connected with the head end of the three-phase distribution line, the low-voltage end of the three-phase main winding is in star connection, and the neutral point of the three-phase main winding is grounded; the on-load voltage regulation switch group comprises six on-load voltage regulation switches which are respectively configured on the low-voltage side of the three-phase main winding and the three-phase secondary winding and provide three-phase first compensation voltage in a cross series connection mode; a distributed static synchronous series compensator DSSC provides a three-phase second compensation voltage; and the three-phase first compensation voltage and the three-phase second compensation voltage are superposed to synthesize a three-phase compensation voltage, and the three-phase compensation voltage is injected into a three-phase distribution line through a three-phase isolation transformer. The invention provides a series hybrid topology consisting of a DST (Digital Subscriber Terminal) and a DSSC (Digital Subscriber Subscriber Center).

The present invention belongs to the technical field of transformer voltage regulation, and relates to an on-load tap changer. The on-load tap changer comprises: a tap changer body and a driving mechanism fixed on the tap changer body, wherein the tap changer body comprises a housing; a plurality of insulating fixing plates, which are lined up and are perpendicularly fixed at the bottom of the housing at equal intervals; a rotary disk, comprising grooved wheels and a cam disk, which are coaxially and integrally formed, wherein the cam disk is rotationally connected to the insulating fixing plates, and the grooved wheels are connected to the driving mechanism; a plurality of vacuum tubes, which are respectively fixed to the insulating fixing plates; and a plurality of transmission mechanisms, wherein each transmission mechanism comprises a lifting lever and a push-back spring. In the present invention, when the driving mechanism drives the grooved wheels to rotate for voltage regulation, the cam disk is synchronously driven to rotate, then, the lifting lever and the push-back spring of each transmission mechanism are used to drive a movable end of each vacuum tube to move back and forth to implement arc extinguishing by means of switching, thereby implementing on-load voltage regulation of a transformer; and the vacuum tube, the transmission mechanism and the grooved wheel are located on the same insulating fixing plate, and the number of parts of the transmission mechanism is also greatly reduced, thereby effectively reducing the size of the tap changer.

The embodiment of the invention provides an on-load tap-changer detection method, electronic equipment and a piezoelectric sensor. The method comprises the following steps: calculating internal pressure generated by a preset piezoelectric crystal in the piezoelectric sensor; calculating a resistance change rate in a Wheatstone bridge preset in a piezoresistive semiconductor film on the upper side of the piezoelectric sensor based on the internal pressure; calculating a differential voltage signal based on the resistance change rate; current state information of the on-load tap-changer is determined according to the differential voltage signal and a preset threshold value, the state information comprises whether the on-load tap-changer is abnormal or not and a current abnormal type of the on-load tap-changer, and the preset threshold value comprises a first threshold value associated with a partial discharge state and a second threshold value associated with a vibration state; the first threshold is far greater than the second threshold. Therefore, whether the on-load tap-changer is abnormal or not can be monitored more comprehensively and efficiently, and the current abnormal state of the on-load tap-changer can be accurately determined.

The application belongs to the technical field of power distribution network automation, and particularly relates to a power distribution transformer intelligent regulation and control method and system based on energy efficiency evaluation, which comprises the following steps: collecting the low-voltage side current, rated current, no-load loss and load loss of a power distribution transformer, and calculating the load rate; obtaining the fluctuation intensity according to the standard deviation of the load rate in a sliding window, and obtaining the change gradient by subtracting the load rates at adjacent time points; obtaining the direction consistency index according to the consistent degree of the directions of the change gradient in a preset number of steps; calculating the noise covariance according to the fluctuation intensity and the direction consistency index, and obtaining the smoothed load rate by substituting the Kalman filter equation; dynamically determining the threshold step number according to the direction consistency index, calculating the smoothed total loss, and determining the preset energy efficiency threshold according to the no-load loss and the load loss. The application reduces the tap changer regulation frequency and prolongs the service life of the contact.

The invention belongs to the technical field of transformer gear calibration, and particularly discloses an oil immersed distribution transformer gear calibration device and method based on dynamic positioning, the calibration device comprises a gear shifting device, and the gear shifting device comprises a position detection circuit board used for detecting the real-time position of a transformer gear; a motor; a transmission assembly is arranged at the output end of the motor and used for controlling the transformer tap switch to rotate to the maximum gear and then rotate towards the first gear. According to the invention, the problem of large gear shifting error is solved, the stability of equipment and the precision of the gear shifting process are improved, and efficient operation of the transformer under different loads and working conditions is ensured.

The present disclosure relates to a vacuum interrupter (1) for an on-load tap changer (10), the vacuum interrupter (1) comprising a cylindrical housing (12) arranged on an axis (z), the housing comprising a wall (14) enclosing a hermetically sealed inner volume (16), the wall (14) further comprising a ceramic bottom portion (15) extending perpendicular to the axis (z), the wall (14) of the housing (12) comprises a first optical interface (18) between the internal volume (16) and an external environment (20) outside the housing (12), the first optical interface (18) being configured to be transparent to at least one optical wavelength, the internal volume (16) comprising a light guide (22) leading to the environment of the internal volume (16), a switch (34) arranged coaxially with the housing (12) on an axis (z) and located within the internal volume (16) of the housing (12), the vacuum interrupter (1) further comprises a shielding element (40) arranged coaxially with the switch (34), in which the light guide (22) is arranged recessed relative to the inner surface (32) of the ceramic bottom portion (15) in the wall (14) of the housing (12), and the shielding element (40) is arranged between the switch (34) and the light guide (22).

The invention discloses a method and a system for judging an on-load tap-changer for a transformer. The method comprises the following steps of: 1, synchronously acquiring multi-source signals; step 2, signal preprocessing; step 3, multi-dimensional feature extraction; 4, generating a dynamic threshold value; step 5, state judgment; 6, self-adaptive compensation is carried out; step 7, backtracking historical data; and step 8, remote communication. According to the invention, multi-source signals are synchronously acquired, vibration and current signals are acquired by using an embedded sensor array, and the comprehensiveness and reliability of signal acquisition are improved; during signal preprocessing, denoising and time-frequency matrix construction are respectively performed on different signals, so that the signal quality is improved; in multi-dimensional feature extraction, four-dimensional feature vectors are formed, dynamic threshold generation is combined with multiple algorithms, and three-level alarm is triggered through state judgment; the self-adaptive compensation link adjusts the feature weight, supports historical data backtracking, and uploads a result through a Modbus-TCP protocol to guarantee the operation safety of a power grid.

A method analyses a state of an on-load tap-changer. The on-load tap-changer has at least one vacuum interrupter for switching between winding taps of a transformer. The method includes: capturing real-time data with respect to the on-load tap-changer; determining tap-changer-specific parameters; and determining at least one characteristic value for ascertaining a state index of the on-load tap-changer on the basis of the real-time data and the tap-changer-specific parameters. The state index includes a period of time until a due maintenance, a remaining service life, or a remaining number of switching processes of the on-load tap-changer.

The invention discloses an on-load tap-changer oil chamber pressure monitoring method for an extra-high voltage converter transformer. Comprising the steps of collecting pressure, environment and operation condition data, performing data cleaning and normalization processing, establishing a pressure prediction model, extracting features, selecting an algorithm optimization model, performing pressure monitoring and fault early warning, calculating deviation, judging abnormity, analyzing fault types and performing early warning. And during acquisition, various sensors are adopted and are preferably arranged. Data processing has a plurality of specific operations. The model adopts an optimization means of a bidirectional LSTM network. Fault analysis adopts a decision tree method and is combined with oil chromatography data verification, and a three-dimensional fault traceability technology is also added. Compared with the prior art, the method has the advantages that the prediction accuracy is improved by collecting the multi-dimensional data, the abnormity is timely found through real-time monitoring, the model performance is improved through data preprocessing, the phenomena of false alarm and missing alarm are reduced, and the accuracy and reliability of the monitoring result are improved.

The invention relates to a load transfer switch (1) for a load tap changer (2), comprising at least one vacuum interrupter (30), a handling element (50) which is mechanically connected to the vacuum interrupter (30) on a first end (51) and has a roller (53) on a second end (52), a handling body (10) which has a base body (11) and at least one cam (20), wherein the vacuum interrupter (30) is handled via the handling element (50) by the roller (53) being driven over the handling body (10), at least one part (21) of the cam (20) having a higher strength than the base body (11).

The application discloses a kind of on-load tap-changer monitoring devices, methods, equipment and storage medium, the device includes position sensor, current sensor and information acquisition processor, position sensor is set to the transmission assembly of on-load tap-changer, for detecting the action information of on-load tap-changer switching knife switch, current sensor is set to the power electronic component of on-load tap-changer and the loop of switching switch, for detecting the current information of the power electronic component, information acquisition processor is used to receive action information and current information, and action information and current information are exported.The on-load tap-changer monitoring device of the embodiment of the application can monitor the action information of switching knife switch and the current information of power electronic component in real time by installing position sensor on transmission assembly, setting current sensor in the loop of power electronic component and switching switch, installation position is reasonable, and it is convenient to monitor on-load tap-changer internal information.

The invention relates to a load tap changer (10) for switching over between winding taps (N1,..., N J ,..., N N ) of a regulatable transformer (1) without interruption, comprising at least one selector unit (30) for preselecting to a selected winding tap (N J ) without power, at least one load switching unit (40) for actually load switching from a previous winding tap (N J _i) to the preselected winding tap (N J ), at least one gear mechanism (50) with a first gear wheel (31) and a second gear wheel (41), wherein the first gear wheel (31) is assigned to the selector unit (30) and the second gear wheel (41) is assigned to the load switching unit (40), a drive shaft (60) which is actuated by a motor drive (70), the first gear wheel (31) and the second gear wheel (41) are directly in mechanical action connection with each other, so that the gear wheels (31, 41) can be actuated simultaneously, the drive shaft (60) can drive the first gear wheel (31) or the second gear wheel (41).

The application discloses a high-voltage load-tap switching device and relates to the technical field of tap switches. The high-voltage load-tap switching device comprises a switching mechanism, a driving mechanism and a recovery mechanism. The switching mechanism is used for completing tap switching of high voltage. The driving mechanism provides power for switching of the switching mechanism. In the application, the second moving contact is separated from the second static contact to generate an electric arc before the first moving contact is switched, and the arc is extinguished by triggering a pressure accumulator pump to release sulfur hexafluoride gas. The sulfur hexafluoride gas has the characteristics of cooling, ion removal and flameout prevention, and the arc is quickly extinguished to create an arcless environment for high-voltage switching of the first moving contact, thereby avoiding ablation of the contact by the arc and improving the safety of equipment operation. After the arc is extinguished, the negative pressure pump is triggered by meshing transmission of the internal gear and the rack to suck the sulfur hexafluoride gas in the left cavity into the recovery tank, so that the gas is quickly recovered. The economic loss caused by waste of the gas is reduced, the risk of equipment aging is lowered, and the service life of the equipment is prolonged.

The invention discloses an autotransformer with a medium-voltage regulating coil located at a high-voltage coil, and belongs to the technical field of transformer manufacturing, the winding directions of a high-voltage coil upper half phase and a high-voltage coil lower half phase are opposite, and the head ends of the high-voltage coil upper half phase and the high-voltage coil lower half phase are connected in parallel and then are led out through a high-voltage outgoing line; the medium-voltage regulating coil is embedded in the high-voltage coil, the head ends of the upper half phase of the medium-voltage regulating coil and the lower half phase of the medium-voltage regulating coil are connected in parallel and are connected with the tail end of the high-voltage coil, and the tail ends of the upper half phase of the medium-voltage regulating coil and the lower half phase of the medium-voltage regulating coil are connected with the head end of the medium-voltage coil; the medium-voltage regulating coil is provided with a plurality of taps including a first-stage tap to a last-stage tap; the head end of the first-stage tap is connected with the tail end of the high-voltage coil, the tail end of the last-stage tap is connected with the head end of the medium-voltage coil, and a medium-voltage outgoing line is led out from each tap through a tap selector of the tap switch; a neutral point outgoing line is arranged at the tail end of the medium-voltage coil.

The utility model discloses a simple on-load tap-changer switching core assembling structure which comprises a main shaft and a moving contact group. The moving contact group comprises a moving contact support plate, a transition contact, a contact and a resistance plate; the moving contact group sleeves the outer side of the main shaft; the main shaft is a spline shaft; the moving contact support plate is provided with a spline groove, and the spline groove is matched with the spline shaft, so that the moving contact support plate is fixed on the outer side of the main shaft. According to the utility model, a drilling process is canceled on the main shaft, a structure that the spline groove is matched with the spline shaft is adopted, and the moving contact support plate is fixed on the main shaft, so that the strength of the main shaft is ensured, the running reliability of the tap switch is improved, and meanwhile, the body health of operators is ensured.

To provide an automatic voltage balancing device and an automatic voltage balancing method that can improve a three-phase unbalanced voltage in a distribution line.SOLUTION: An automatic voltage balancing device is composed of a transformer portion and a control portion. The transformer portion connects a tap changer composed of a mechanical diverter switch and a tap selector in series with a distribution line, and the tap changer changes the tap while the transformer portion is being operated. When a substation is connected to a primary side, the control portion calculates an average value of a primary voltage of the tap changer, and controls the voltage such that a secondary voltage of each phase approaches the average value. When the substation is connected to a secondary side, the control portion calculates an average value of a secondary voltage of the tap changer, and controls the voltage such that the primary voltage of each phase approaches the average value.SELECTED DRAWING: Figure 1

An energy conversion device 100 for an electrolysis system (150) comprises: an adjustable transformer (101) having a primary side (102) connectable to an AC grid (103) via a point of common coupling, a secondary side (104) and a tap switch (105); a rectifier transformer (106, 107) having a primary side (108, 109) configured to provide a secondary side voltage differing by a predetermined phase shift; a thyristor rectifier unit (114, 115, 116, 117) forming a multi-pulse rectifier system (118) that receives the secondary side voltage and provides a DC current to the electrolyser unit (119, 120, 121, 122); and a protection controller unit 133 for connecting / disconnecting the device to / from the power grid as a function of a comparison of the secondary-side voltage to a corresponding secondary-side threshold voltage, where the multi-pulse rectifier system comprises a synchronization control circuit (123, 124, 125, 126) providing thyristor gate pulses at an emission angle synchronized with the secondary-side voltage, and a protection controller unit 133 for connecting / disconnecting the device to / from the power grid as a function of a comparison of the secondary-side voltage to a corresponding secondary-side threshold voltage. And wherein the respective secondary-side threshold voltage is determined from a nominal threshold voltage specified by a grid guideline at the point of common coupling and a physical transformer parameter adjusted according to tap switch position information (129).

The present invention discloses a method for monitoring an on-load tap changer transmission mechanism based on sparse filtering, which relates to the technical field of on-load tap changer transmission mechanism detection. The method involves performing multiple gear switching on the on-load tap changer to collect vibration signals of the transmission mechanism during the on-load tap changer switching process. A sparse filtering network-based vibration signal characteristic distribution matrix of the on-load tap changer transmission mechanism is calculated based on the vibration signals. The eigenvalues ​​and eigenvectors of the principal component components of the vibration signal characteristic distribution matrix are calculated. The weighted mean of the elements of the statistic and the corresponding control limits are calculated based on the eigenvalues ​​and eigenvectors of the principal component components of the characteristic distribution matrix. The mechanical state of the transmission mechanism is determined based on the weighted mean of the elements of the statistic and the corresponding control limits. The method of the present invention efficiently and accurately determines the mechanical state of the on-load tap changer transmission mechanism by performing real-time monitoring and computational analysis of the vibration signals of the transmission mechanism during the on-load tap changer switching process.

The present invention discloses a method, system, device and storage medium for high-frequency harmonic protection of a flexible direct current valve group. The method for high-frequency harmonic protection of a flexible direct current valve group calculates the harmonic components obtained in real time in a first frequency range, thereby avoiding the influence of transformer saturation and background harmonics when calculating the 2-7 harmonic components, and reducing the false triggering phenomenon of protection action output tripping; by prohibiting the gear adjustment of the commutator tap changer when the comprehensive value of the harmonic components is greater than the first threshold value and the first duration reaches the first delay, the harmonic protection performance is improved; by controlling the non-master control valve group to lock when the flexible direct current valve group is a flexible direct current dual-valve group and the second duration reaches the preset second delay, the equivalent impedance of the flexible direct current dual-valve group as a whole is changed, the resonance condition between the flexible direct current dual-valve group and the high-frequency harmonic system of the flexible direct current valve group is destroyed, the high-frequency resonance between the master control valve group and the system is exited, and the problem of simultaneous locking of the dual-valve group is avoided.

The utility model discloses a self-coupling phase-shifting transformer with a safe switching function, and particularly relates to the field of self-coupling phase-shifting transformers, which comprises an iron core, a high-voltage winding, a voltage-regulating winding, a public winding, a phase-regulating winding, a voltage-regulating on-load tap-changer, a phase-regulating on-load tap-changer and a no-load reversing tap-changer, the iron core comprises three central columns, and each central column is sequentially provided with a phase modulation winding, a voltage regulation winding, a common winding and a high-voltage winding from inside to outside. According to the utility model, when the potential of the tail end of the common winding is zero and the phase modulation on-load tap-changer is at a rated tap-changer position, the second electric mechanism of the no-load reversing tap-changer can be operated, and at the moment, the self-coupling phase-shifting transformer is at a zero phase angle position; the polarity conversion of the no-load commutation tap-changer can be ensured under the specific condition of zero phase angle, the safe operation of the no-load commutation tap-changer can be protected, and the safe switching is realized.