36 results about "DC distribution system" patented technology

The invention relates to the technical field of power electronics and power supply and distribution, and discloses a data center AC / DC power distribution system input and output voltage and current monitoring method, which comprises the following steps: deploying an intelligent sensing unit with edge computing capability at each monitoring node, sampling according to a basic frequency, and extracting effective values, harmonic distortion rates, differential change rates and other characteristics of voltage and current in real time; judging that the system is in a steady state, a quasi transient state or a strong transient state according to the multi-stage dynamic threshold value, and respectively executing feature abstract uploading, local high-frequency backtracking or collaborative full-waveform synchronous acquisition; and the central server classifies and stores the data, constructs a state evolution model, and dynamically optimizes threshold parameters. The system comprises an intelligent sensing unit, a central monitoring server and an industrial Ethernet link. According to the method, the steady-state data transmission quantity is remarkably reduced, transient details are completely captured, and adaptive adjustment of the monitoring sensitivity is realized.

This invention discloses an active damping control method for bipolar DC distribution systems based on modulus decomposition. It incorporates line coupling into the system's stability criteria and active damping parameter design, deriving the pole-mode transformation matrix of the metal-return bipolar DC distribution system and obtaining a decoupling model of the bipolar DC line in the modulus component space. The modulus models of the source-side converter and load are also derived. Based on the established decoupling model of the bipolar DC distribution system in the modulus component space, an active damping control method based on modulus decomposition is proposed. This invention considers the impact of DC distribution lines on stability, incorporating line coupling into the system's stability criteria and active damping parameter design. The modulus damping control scheme proposed in this invention can more effectively suppress instability caused by the negative impedance characteristics of constant power loads and also provides a basis for parameter adjustment.

The embodiment of the invention provides a mining DC power distribution system. In one specific embodiment, the system comprises a rectification filtering unit, an energy storage assembly, a first power-off change-over switch, a second power-off change-over switch, relay power generation equipment and a controller. The controller is used for acquiring a first conversion state of the first power-off automatic conversion switch, responding to the first conversion state as an instruction that the output end of the first power-off automatic conversion switch is connected with the standby input end, controlling the power generation equipment to be started, acquiring an operation state of the power generation equipment, responding to the operation state as an operation ready instruction, and controlling the power generation equipment to be started. And the coil of the relay is controlled to be electrified. The mining DC power distribution system can stably and continuously supply power for a long time.

The present application relates to the field of power electronics and power supply and distribution technology, and discloses a monitoring method for input and output voltage and current of an AC / DC power distribution system in a data center, which comprises: deploying intelligent sensing units with edge computing capabilities at each monitoring node to sample at a basic frequency and extract real-time characteristics such as effective value, harmonic distortion rate and differential change rate of voltage and current; determining whether the system is in a steady state, quasi-instantaneous state or strong instantaneous state according to multi-level dynamic threshold values, and performing feature abstract upload, local high-frequency backtracking or collaborative full-waveform synchronous acquisition respectively; storing data in a central server and constructing a state evolution model to dynamically optimize threshold parameters. The system comprises intelligent sensing units, a central monitoring server and an industrial Ethernet link. The present application significantly reduces steady-state data transmission volume, completely captures transient details and realizes adaptive adjustment of monitoring sensitivity.

The invention provides a DC micro-grid insulation resistance monitoring device for an optical storage DC flexible system. The DC micro-grid insulation resistance monitoring device comprises a detection circuit and a controller communicating with the detection circuit. The device is connected to multiple paths of positive direct current buses including distributed photovoltaic branches and energy storage system branches in a direct current micro-grid through a Y-shaped connecting circuit, and relay logic is switched by utilizing a controller to obtain an output voltage signal. The core judgment logic is to compare whether the output voltage is in a reasonable interval defined by a coefficient gamma (the value can be dynamically adjusted according to the energy storage voltage grade) and the bus voltage, so that the insulation abnormity of the direct current micro-grid system under the flexible interaction working condition is quickly identified, and an alarm is given. According to the device, the operation process of multi-branch complex impedance is simplified, and the detection efficiency of the ground insulation state of the direct current end is remarkably improved.

The invention discloses a direct-current power distribution system energy mutual aid and power coordination control method, application and system, aiming at non-ideal disturbance, load fluctuation and parameter uncertainty existing in the system, VFESO is introduced, rapid estimation and compensation of generalized disturbance are realized through self-adaptive adjustment of observation gain and feedback bandwidth, and based on an observation result of the VFESO, the energy mutual aid and power coordination control of the direct-current power distribution system is realized. An improved reference feed-forward control law is designed, the reference current change rate and the disturbance observed quantity are comprehensively considered in the control law, a disturbance compensation item is directly introduced into control input, and feed-forward compensation and dynamic linearization of a current control loop are achieved; according to the invention, the system can maintain high-precision voltage and power control under the conditions of new energy fluctuation, energy storage switching and load disturbance.

The invention relates to a solid-state switch fault protection system for a direct-current power distribution system, which is applied to a ship direct-current power distribution system, the ship direct-current power distribution system comprises a direct-current bus, the direct-current bus is divided into a left direct-current bus and a right direct-current bus, and the left direct-current bus and the right direct-current bus are connected through a solid-state switch. The solid-state switch fault protection system comprises an energy management system, a converter and the like which are connected with a ship direct-current power distribution system, a power supply is connected with a direct-current bus through the converter, a propelling system is connected with the direct-current bus through a motor driver module, and a side propelling system is connected with the direct-current bus through a power inverter module. The energy management system adopts a redundant PLC control system based on a looped network so as to quickly monitor faults of the solid-state switch, and can quickly provide a control scheme according to an online system. In addition, the system has the advantages of good stability, safety and the like.

This invention discloses an adaptive DC voltage control method for a three-terminal flexible DC distribution system, belonging to the field of power technology. The method includes the following steps: constructing a three-terminal flexible DC distribution system; analyzing the deviation value of the DC voltage in the three-terminal flexible DC distribution system; determining the magnitude of the DC voltage deviation value; and controlling the change and voltage value of the DC voltage in the three-terminal flexible DC distribution system. This invention superimposes an active power command correction controller onto the constant power control mode (PQ mode) of the flexible DC converter, enabling the flexible DC converter to dynamically adjust the output active power according to the instantaneous state of the DC voltage, thereby improving the DC voltage recovery speed.

The application discloses a three-phase grid-connected converter control method, a circuit, a device and a medium, and relates to the technical field of AC-DC power distribution systems. The three-phase grid-connected converter control method provided by the application establishes a mathematical model of the three-phase grid-connected converter, combines the causes and suppression mechanism of the leakage current, controls the filter capacitor voltage in the zero sequence loop to be a constant value through a PI regulator, and effectively attenuates the leakage current. The phase angle of the grid voltage is obtained in a three-phase stationary coordinate system, the sampling quantity is coordinate-transformed according to the angle, a modulation signal is obtained, and the power switch tube in the grid-connected converter is controlled according to the modulation signal. Since only one connected wire needs to be added between the middle point of the filter capacitor and the common point of the lower bridge arm in the scheme, the cost is low, and the leakage current caused by the existence of the parasitic capacitance of the DC side power distribution device to the ground can be limited to the microampere level.

The invention discloses a DC power distribution network interelectrode short circuit protection method and system based on boundary elements, and belongs to the technical field of DC power distribution system protection. The method comprises the following steps: configuring a capacitor as a boundary element at the tail end of a DC line protection area; current is collected in real time, the change rate is calculated, and protection is started if a threshold value is exceeded; performing high-speed sampling on the current after starting; performing wavelet transform on the sampled data, and extracting high-frequency energy and low-frequency energy of the current; and calculating a high-frequency and low-frequency energy ratio, if the ratio is greater than a preset threshold value, determining that an intra-region inter-electrode short-circuit fault occurs and a tripping instruction is sent out, otherwise, determining that the intra-region inter-electrode short-circuit fault occurs or no fault occurs. According to the method, the bypass effect of the boundary capacitance on the high-frequency fault current is utilized, the obvious characteristic difference of the internal and external faults of the area is manufactured, the difference is quantified through wavelet transform, rapid and accurate fault recognition and isolation based on local quantity without depending on communication are achieved, and the problem that in the prior art, quickness and selectivity are difficult to consider at the same time is solved.

The utility model belongs to the technical field of ship power distribution, and specifically discloses a marine double-bus redundant DC power distribution system. Comprising a first direct-current busbar left, a first direct-current busbar right, a second direct-current busbar left, a second direct-current busbar right, a first circuit breaker, a second circuit breaker, a lithium battery pack, a first propulsion inverter cabinet, a first daily inverter cabinet, a second propulsion inverter cabinet, a second daily inverter cabinet, a direct-current voltage stabilizer and a system charging socket box. According to the utility model, through setting the first direct-current busbar left, the first direct-current busbar right, the second direct-current busbar left, the second direct-current busbar right and the switching relation thereof and adopting an operation mode that one group of busbars works and the other group of busbars is standby, flexible and balanced distribution of a power supply and a load is realized, and all loops can work without power failure; once any busbar or branch has a fault, the standby busbar is immediately started so as to start the standby loop, so that no power loss and no power reduction of the whole ship are ensured, and all equipment and components of the whole system are subjected to redundancy design so as to ensure that the power distribution system always supplies power normally.

The application discloses a kind of based on truncation coefficient and realizes state merging DC distribution system reliability evaluation method, it is related to DC distribution system field.According to the multiple operating states presented by the coupling of DC distribution system "source load", the system state space model is established, according to the internal relationship between different operating states, the state merging condition is optimized, the fault tree analysis method is combined with Markov process, the state merging method based on truncation coefficient is proposed, and the reliability index of DC distribution system is calculated according to the system operating state after merging.The application first applies the state merging idea to the reliability evaluation of DC distribution system, combines the fault tree analysis method with Markov process, determines the truncation coefficient by the convergence process of truncated state probability C While ensuring accuracy, the solving efficiency of merged state transition rate is improved, the system state merging under differentiated transition rate is realized, and the application range of state merging in the reliability evaluation of DC distribution system is expanded.

The invention belongs to the technical field of power distribution in a nuclear power plant, and particularly relates to a direct-current power distribution system applied to the nuclear power plant, which comprises at least two direct-current topological power distribution lines used for accessing different high-voltage alternating-current power supplies outside the plant, and each direct-current topological power distribution line comprises a shared rectifier and two sub-power distribution lines. Each sub-distribution line is provided with a DC bus of a first distribution voltage, a DC bus of a second distribution voltage, DC buses of two third distribution voltages and a standby DC bus of a third distribution voltage. The first direct current bus and the second direct current bus of the third power distribution voltage are used for providing direct current of the third power distribution voltage for the in-plant load and providing alternating current of the third power distribution voltage through the inverter; one end of the rectifier is used for accessing an off-plant high-voltage AC power supply, and the other end is connected to the DC bus of the two first distribution voltages.

The application discloses a kind of multi-dimension multi-resource comprehensive voltage regulation optimization methods of multi-voltage grade bipolar direct current distribution network, comprising:1 establishes the control model of bipolar direct current transformer DCT, electric vehicle, energy storage equipment and power flow controller;2 establish multi-dimension multi-resource coordinated control model of multi-voltage grade bipolar direct current distribution network;3 establish comprehensive voltage regulation optimization model of multi-voltage grade bipolar direct current distribution network;4 establish the linearization and relaxation model of the constraint of bipolar direct current distribution network comprehensive voltage regulation model;5 by solving multi-voltage grade bipolar direct current distribution network, obtain the comprehensive voltage regulation optimization strategy of bipolar direct current distribution system.The application can realize the quick response load demand and distributed energy fluctuation, ensure the stability of low-voltage side voltage, effectively control the voltage imbalance degree and over-limit problem between positive and negative electrode, improve the stability of system voltage.

The invention discloses an AC / DC power distribution system typical scene generation method considering source-load space-time correlation, and relates to the technical field of scene generation, and the method comprises the steps: building a digital representation model based on the typical grid topology of an AC / DC power distribution system; according to new energy spatio-temporal evolution characteristics, constructing a time correlation model of wind and light output based on a dependency function-state transition chain, and establishing a spatial correlation model of wind and light output based on a multivariate hierarchical tree; constructing a load time sequence optimization model driven by a daily load characteristic index according to the random volatility of the daily load, and constructing a charging load generation model according to different user groups of the electric vehicle; establishing a flexibility demand and supply quantification model; and constructing an original scene according to the established model, and clustering the generated original scene to obtain a typical scene of the AC / DC power distribution system. According to the method, the source-load space-time correlation can be extracted based on historical data, the original scene is generated, and the typical scene is obtained through clustering.

The application provides a low-voltage transfer protection device for the end of a DC power supply line of rail transit, comprising a voltage transmitter A, a voltage transmitter B, a low-voltage protection measurement and control unit and a transfer cable, the input end of the voltage transmitter A is connected with the positive pole and the negative pole of the end of the DC power supply line respectively, and the output end is connected with the low-voltage protection measurement and control unit, the input end of the voltage transmitter B is connected with the positive pole of the end of the DC power supply line and the ground wire respectively, and the output end is connected with the low-voltage protection measurement and control unit, and the output end of the low-voltage protection measurement and control unit is connected with the DC distribution system in the traction substation through the transfer cable. And a protection method, whether the voltage measured by the two voltage transmitters exceeds the setting value is judged respectively, if the setting value is exceeded, the DC distribution system controls the corresponding line circuit breaker to transfer. The application significantly improves the reliability, speed and sensitivity of the over-current protection of the DC line, reduces the engineering investment and the operation and maintenance cost.

A pre-charge circuit for charging a DC link capacitor is provided. The pre-charge circuit may include: a first semiconductor switch for coupling to a first terminal of a high-voltage source; a first inductor for coupling to the first semiconductor switch and the first terminal of the capacitor; a second semiconductor switch for coupling to a second terminal of the high-voltage source; a second inductor for coupling to the second semiconductor switch and the second terminal of the capacitor; and a diode coupled to the first semiconductor switch, the second semiconductor switch, the first inductor, and the second inductor, and coupled in parallel with the capacitor.

The invention discloses a low-voltage flexible DC micro-grid fault positioning method based on an improved Tiancattle swarm algorithm. According to the method, the fault point can be accurately positioned when the inter-electrode short-circuit fault or the single-electrode grounding fault occurs in the flexible direct-current power distribution network. The method is slightly influenced by excessive resistance, and a fault positioning problem is converted into a fault parameter identification problem. And in combination with the improved Tiancattle swarm algorithm, the accuracy of fault point positioning can be improved, errors are reduced, and the information distortion resistance is improved. The method is of great significance in improving the safety and reliability of the direct-current power distribution system.

Voltage command values are set according to voltage fluctuations of a plurality of power supply sources, and one of outputs from a plurality of power supply circuits which output DC voltages obtained by performing conversion according to the voltage command values is supplied to a power conversion circuit as control power so that the system can be continuously operated even at the time of an abnormality due to a device failure and a power outage, and control power consumption can be suppressed in the case of voltage fluctuations of the power supply sources.

The disclosure is directed to a device for voltage equalization of a plurality of two-terminal networks. The device includes a current-limiting component, and connection pairs, each having a first connection and a second connection for connecting the two-terminal networks. Two or more of the first connections are each connected to an input. In addition, two or more of the first connections are each connected to an output via a second switch. The second connections are connected or switchably connected to a common reference potential. The device sets switching states of switches by means of a control unit and / or by means of voltages applied to the first connections in such a manner that the current-limiting component intakes power in its input and not in its output, and the current-limiting component outputs power from its output and not from its input.

The application provides a bipolar direct current power distribution system architecture and an operation method based on a virtual voltage equalizer. Distributed power supply units and load units are regarded as virtual voltage equalizers in the bipolar direct current system, and the bipolar direct current power distribution system can realize positive and negative voltage equalization without additionally adding voltage equalizers. The virtual voltage equalizer can effectively realize voltage equalization of the positive and negative poles of the bipolar direct current system based on a three-port converter connected by the load and the distributed power supply, and compared with a traditional voltage equalization mode, the operation method based on the virtual voltage equalizer can effectively improve the operation efficiency of the system.

The application belongs to the technical field of power distribution in nuclear power plants, and particularly relates to a direct current power distribution system applied to a nuclear power plant, comprising: at least two direct current topology power distribution lines for connecting different off-site high-voltage alternating current power sources, wherein the direct current topology power distribution lines comprise a common rectifier and two sub power distribution lines. Each of the two sub power distribution lines is arranged with a first power distribution voltage direct current bus, a second power distribution voltage direct current bus, two third power distribution voltage direct current buses, and a third power distribution voltage backup direct current bus, and the first and second third power distribution voltage direct current buses are used to provide third power distribution voltage direct current for the on-site load and third power distribution voltage alternating current through an inverter; one end of the rectifier is used to connect the off-site high-voltage alternating current power source, and the other end is connected to the two first power distribution voltage direct current buses respectively.

To provide a power conversion device which parallels off only a switch of a breaking part just above a short-circuit part without causing unnecessary power outage.SOLUTION: A power conversion device includes: a power converter which is provided between a power supply part and a plurality of breaking parts provided so that a breaking current value decreases as one progresses from an upstream to a terminal end of a power distribution system and converts power supplied from the power supply part to output DC power; and a control part which increases output current so that the breaking parts are paralleled off in order from the breaking part with the smallest breaking current value after output current of the power converter is lowered below the lowest breaking current value in the breaking current values required for opening the switches of the plurality of breaking parts when a short-circuit accident occurs in the power distribution system.SELECTED DRAWING: Figure 2

1. Name of the product in this design: Diverter. 2. Application of this design: This design is used for current measurement in DC power distribution systems via shunts. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

The invention provides a novel direct-current power distribution system, which combines the advantages of single-pole and double-pole hybrid power distribution and is applied to a medium-low voltage power distribution scene. Through the innovative system architecture design and droop control strategy, the fault current is effectively reduced, the reliability of the system is improved, the possibility of element damage is reduced, in addition, after the fault occurs, the release DC power distribution strategy can effectively isolate the fault area, reduce the fault influence range and improve the stability of the system. And the strategy can also reduce the use of cables and save the system cost. Simulation verification shows that compared with a traditional bipolar system, the direct current power distribution system is better in the aspects of fault current control, post-fault voltage stability and power loss.

This disclosure relates to an AC / DC power distribution system, comprising: at least one first DC converter and an AC / DC power distribution circuit. The input terminal of the first DC converter is connected to a DC transmission bus, and the output terminal of the first DC converter is connected to a DC collecting bus. The first DC converter is used to convert the bus DC power provided by the DC transmission bus into first DC power. The AC / DC power distribution circuit includes a power collection node and multiple AC / DC converters. The power collection node includes a power dispatching module. The power dispatching module is used to divide the first DC power into multiple second DC power of the same voltage level and allocate them to the corresponding AC / DC converters according to the power demand of multiple AC zones. The AC / DC converters are used to convert the second DC power received from the power collection node into first AC power and provide it to the corresponding AC zones. This disclosure enables active power distribution to multiple AC zones.

The application discloses a direct current power distribution system, and belongs to the technical field of power supply. The direct current power distribution system comprises an AC-DC voltage converter, a bidirectional DC voltage converter, an energy storage module, an energy storage manager and a controller. When the residual power of the energy storage module is relatively large, the energy storage module can output direct current to the power utilization equipment, thereby providing power for the power utilization equipment. In this way, the time length for which the power utilization equipment is provided with power from the AC bus can be reduced, various problems caused by the AC power distribution system in providing power for the power utilization equipment can be solved to a certain extent, and power supply power quality is improved.

This invention discloses an enhanced droop control method to improve the stability of a multi-terminal low-voltage DC distribution system. The method includes processing the DC current feedforward value using a compensation filter set in the DC distribution system's droop control loop to obtain a virtual impedance. This virtual impedance is then used to reshape the output impedance of the source-side subsystem of the DC distribution system. The constraints of the compensation filter include DC component amplitude constraints, target frequency band phase constraints, and system stability margin constraints. The DC component amplitude constraint ensures that the virtual impedance amplitude at 0 Hz is much smaller than the source-side output impedance amplitude. The target frequency band phase constraint raises the phase of the virtual impedance within the target frequency band to meet phase requirements. The system stability margin constraint designs the compensation filter parameters based on the operating condition where the original DC distribution system reaches its maximum power stability boundary. This method can improve the overall system stability while avoiding significant changes in steady-state characteristics.

A method for determining the stability of a multi-voltage-level DC distribution system containing multiple DC microgrids is disclosed. The method first confirms that the equivalent admittance of each microgrid subsystem has no right-half-plane poles based on the specific control mode of the interconnecting converter and the equivalent open-loop gain of each microgrid operating independently. Second, based on the two-port network matrix of the interconnecting converter, the multi-voltage-level DC distribution system containing multiple DC microgrids is simplified to a single-bus DC system containing only the distribution bus. The stability of the entire system is then determined using the equivalent impedance ratio. Under the premise that each unit within the system can operate stably independently, the stability of the entire system is guaranteed when the equivalent open-loop gain of each microgrid operating independently and the equivalent impedance ratio on the distribution bus side both satisfy the Nyquist criterion. This invention utilizes the equivalent open-loop gain of each DC microgrid operating independently and the equivalent impedance ratio of the system on the distribution bus side to analyze the stability of a multi-voltage-level DC distribution system containing multiple DC microgrids. It has good flexibility and applicability, and can provide a reliable theoretical basis for the design of multi-voltage-level DC distribution systems.

The invention discloses a multi-voltage-level multi-partition interconnected direct-current power distribution system and a steady-state operation analysis method. The power distribution system forms a core substation-regional substation-looped network node three-partition direct current architecture, and energy level transfer and power coordination control among different voltage levels are realized through combination of multiple layers of topological structures, so that the operation flexibility and the anti-interference stability of the system are improved; the steady-state operation analysis method of the direct-current power distribution system comprises the steps of data modeling and feature dimension reduction, two-layer decoupling power flow solving and global steady-state mapping and prediction, energy state changes under different new energy output conditions can be accurately tracked, and the method has adaptability and convergence in rapid evaluation and multi-scene planning; the method provided by the invention has good assessability and engineering implementability.