11 results about "Unified power flow controller" patented technology

The invention discloses an urban power grid coordination control method and system based on deep reinforcement learning, and solves the technical problem that the current urban power grid coordination control method causes the limitation of the urban power grid power flow adjustment precision. The method comprises the following steps: after acquiring an expert experience data set, normalizing an urban power grid state vector at the current moment to obtain a normalized vector; and pre-training the initial strategy network by minimizing a loss function according to the vector and the expert experience data set to obtain a pre-trained strategy network, and calculating and outputting the active power of the unified power flow controller and the reactive power of the reactive compensation equipment. And in combination with the power parameters and the normalized vector, determining a normalized future state vector and a current reward value by using a power flow equation and a multi-target reward function, optimizing the pre-training network by using a PPO target function and a value network to obtain a target strategy network, and outputting a target action vector as a coordination control scheme.

This invention proposes a transformerless medium-voltage power flow transfer device composed of a capacitor switching circuit and a series active circuit. This effectively solves the problems of high cost, large size, and significant operating losses associated with traditional Unified Power Controllers (UPFCs) and back-to-back converters due to the inclusion of isolation transformers. Furthermore, if only a series active circuit is used for active power transmission, reactive power control is difficult, resulting in a low system power factor when there is a large difference in voltage amplitude between the sending and receiving ends. The proposed device, through the coordinated control of a floating module on the sending end and the passive capacitor switching, brings the voltage amplitudes on both sides closer together, significantly suppressing reactive power deviations during active power transmission and improving power quality during power flow control. Finally, the device can perform power flow transfer control regardless of whether the sending-end voltage amplitude is higher or lower than the receiving-end voltage amplitude, offering high flexibility.

The application relates to a UPFC device fault prediction method based on a wavelet neural network, and comprises the following steps: defining a fault variable of a unified power flow controller; classifying the fault variable, and defining a data acquisition structure for device state monitoring and fault prediction; acquiring signal data of each node of the unified power flow controller, classifying and coding the signal data after filtering and A / D conversion; constructing a device fault prediction model by adopting a wavelet neural network; inputting real-time signal data into the trained device fault prediction model to obtain a device state prediction result output by the device fault prediction model; judging whether a device fault exists according to the device state prediction result; and issuing a fault early warning signal for the predicted device fault. The application realizes multi-dimensional and all-around UPFC online state monitoring, fault diagnosis and fault early warning, predicts specific fault information of the UPFC device in advance, effectively protects the operation safety of the device, and avoids damage to other power electronic elements caused by the UPFC device fault.

The invention belongs to the technical field of power system new energy grid connection, and provides a grid-following type wind power plant grid construction transformation method and system based on a series auxiliary device, a plurality of fans in a grid-following type wind power plant run in a grid-following type, and a plurality of fan sets are connected in parallel and collected at a common connection point after being boosted by a transformer. Performing net construction type transformation through a series auxiliary device; the series auxiliary device adopts a unified power flow controller for centralized network construction type transformation, and at least comprises a parallel side converter and a series side converter; based on the common connection point, a plurality of wind generator sets in the distributed following grid type wind power plant are connected in parallel and collected, and the impedance of a power transmission line is adjusted through the series side converter so as to remodel the port of the wind power plant. And the parallel side converter adopts network construction type control to adjust the power of the network-following wind power plant within a stable range so as to complete centralized network construction type transformation of the network-following wind power plant.

The invention discloses a UPFC (Unified Power Flow Controller) control method, device and equipment considering a line N-1 fault. The method comprises the following steps: acquiring a real-time electrical quantity on a UPFC installation line; identifying the running state of the UPFC system according to the real-time electrical quantity to obtain the type of the running state; if the operation state category is an overload state, calculating the optimal regulation voltage of the UPFC according to a preset power regulation model through a sensitivity analysis method; if the type of the operation state is a short-circuit fault state, adjusting the equivalent impedance current limiting of a UPFC series transformer, triggering a UPFC parallel converter to carry out reactive power regulation, and outputting a voltage reference value; and based on the control coefficient of the inner loop controller and a linear weighting method, realizing UPFC adaptive regulation and control according to the optimal regulation voltage or the voltage reference value. The technical problems that in the prior art, self-adaptive adjustment capability based on the real-time electrical quantity is lacked, and the relation between UPFC control and system short-circuit current limitation cannot be coordinated can be solved.

The invention belongs to the technical field of power flow controllers, and particularly relates to a combined power flow controller. In order to overcome the defects of an existing electromagnetic power flow controller and an existing unified power flow controller, the invention adopts the following technical scheme that the combined power flow controller comprises a phase-shifting transformer, a power supply module and a control module, a series converter; a passive AC fast switch; wherein the phase-shifting transformer adopts a double-core symmetrical structure or a double-core asymmetrical structure, the phase-shifting transformer comprises an exciting transformer unit and a series transformer unit, and a primary winding of the series transformer unit is connected with the series converter and the passive alternating-current quick switch in series and then is connected to a high-voltage alternating-current line. The combined power flow controller has the advantages that large-range high-precision voltage regulation operation is completed through coordinated control of the phase-shifting transformer and the series converter, flexible control over line power flow is achieved, short-circuit current blocking is achieved by arranging the passive alternating-current quick switch, and the short-circuit current level of a system can be effectively limited.

The application belongs to the field of electric power engineering, and particularly relates to a unified power flow controller fault prediction system adopting a device fault prediction model, which comprises a data acquisition and processing module, a fault training module and an online monitoring module; the data acquisition and processing module comprises an AC / DC signal acquisition device, a filtering device, a signal processing device and a data storage module; the online monitoring module comprises a state monitoring module, a fault early warning machine and a display module. The application realizes multi-dimensional and all-round UPFC online state monitoring, fault diagnosis and fault early warning, predicts specific fault information of the UPFC device in advance, effectively protects the operation safety of the device, and avoids damage to other power electronic elements caused by UPFC device faults.

The application provides a multi-terminal flexible direct unified network type control structure and parameter value method, which comprises three branch structures and one total branch structure, the total branch structure comprises common elements of three control structures, the three branch structures correspond to the three control structures one by one, each branch structure comprises residual elements of the control structure corresponding to the branch structure after removing the common elements and a parameter controller; wherein the three control structures comprise a control structure when a receiving end MMC adopts direct current voltage control, a control structure when the receiving end MMC adopts active power control, and a control structure when the MMC is connected to an island system and voltage and frequency of the island need to be established. The application can realize stable control and seamless mode switching of the MMC-MTDC system under different operating conditions.

The invention discloses a topological structure of an energy storage fusion type unified power flow controller. The topological structure comprises a boosting transformer T, a parallel transformer T1, a series transformer T2, an energy storage type series converter B-SEC and an energy storage type parallel converter B-SHC. According to the energy storage fusion type unified power flow controller, an extra high-power isolation type direct-current transformer does not need to be connected into a power distribution system, and the power conversion link is reduced; the wooden barrel effect caused by centralized configuration of the energy storage unit and series-parallel connection of the batteries in the low-voltage direct-current bus is avoided, and the equipment capacity ratio is fully utilized; and furthermore, the battery management system is greatly simplified, the self-detection time of the battery cell cluster is shortened, and the dynamic response speed of the whole system is improved. Therefore, the technical problems that in the prior art, the system cost is high, multi-stage operation regulation and control are complex, fault protection cannot meet requirements, and the system response speed is low are solved.

The invention discloses an optimal control method and system for a distributed photovoltaic power distribution network. The method comprises the following steps: acquiring data information of the distributed photovoltaic power distribution network; taking the minimum voltage deviation and the minimum line loss as targets, combining the data information, and carrying out normalization processing on the voltage deviation and the line loss to obtain an optimized target function; establishing a target constraint condition, and solving the optimization target function by using a particle swarm optimization algorithm under the condition that the target constraint condition is met so as to determine a control parameter value of the UPFC; and adjusting the UPFC controller in real time according to the control parameter value so as to realize the optimal operation of the distributed photovoltaic power distribution network. According to the method, a unified power flow controller (UPFC) is introduced to control power flow, voltage deviation and line loss are optimized with the help of a particle swarm optimization algorithm, and finally the purposes of voltage stabilization and line loss minimization of the power distribution network are achieved, so that the stability of the power grid is ensured, and meanwhile energy loss caused by current flowing is reduced.

The application discloses a disturbance suppression method and system applied to an LCL type unified power flow controller, relates to the technical field of power flow converter power control, and comprises the following steps: constructing an input and output mathematical model of a series side converter system in an s domain according to an LCL type filter, and reducing the order of the input and output mathematical model; performing linear space transformation on the reduced input and output mathematical model, and then compensating for the disturbance generated by the linear space transformation through a state observer LESO; designing a phase lead link based on the frequency characteristics of time delay; calculating current instruction values in a stationary coordinate system according to a power flow equation of the unified power flow controller, and designing a current tracking controller to realize real-time tracking of the current instruction values. The application can solve the technical problem that harmonics affect the output current quality of the series side converter in the related art.