1564 results about "Dc circuit breaker" patented technology

The invention relates to a breaker of a direct current system, in particular to a semi-controlled active injection current high voltage direct current breaker and a realization method thereof. The breaker comprises a high speed switch-thyristor module branch, as well as a lightning arrester branch and a bridge circuit which are connected in parallel with the branch, wherein a capacitor-reactor series branch and a resistor-thyristor series branch are connected in parallel and then connected with middle points of two bridge arms of the bridge circuit; and the two ends of a capacitor are connected in parallel with a charging loop. The breaker is based on a direct current breaking principle by the traditional active injection current manner; semi-controlled power electronic devices are added; a high speed mechanical switch is adopted; the advantage of low loss during normal breakover is kept; and bidirectional current can be broken quickly without an arc. The breaker is simple in circuit topological structure, simple and convenient to control, mature in technology, easy to realize, great in current breaking capability, high in withstand voltage level and strong in expansion capability, and the cost is lowered greatly since the number of the adopted power electronic devices is small.

A dc breaker is connected in a main current path between a first dc circuit and a second dc circuit. The dc breaker has a primary current path connected to the main current path. A mechanical interrupter switch and an electronic breaker switch are connected in series in the primary current path. A secondary current path is provided in parallel with the primary current path. A capacitor is arranged in the secondary current path so as to be connected in parallel with the series-connected switches of the primary current path.

The invention relates to a circuit breaker and a realization method thereof, and specifically relates to a mixed high-voltage direct-current circuit breaker and a realization method thereof. The direct-current circuit breaker is based on the principle of secondary current transfer. A main branch is composed of a quick-action mechanical switch and a current transfer module which contains a full-controlled device, which ensures the advantages of low loss and flexible current transfer control in the state of normal conduction. A first current transfer branch is composed of half-controlled device thyristors connected in series, so that the circuit breaker has strong fault flow capacity and breaking capacity, 'zero voltage and zero current' of the mechanical switch can be maintained long enough, and arc-free switching of the mechanical switch is realized. A second current transfer branch is composed of capacitors with pre-charged voltage, an inductor, and series-connected thyristors. After the thyristors of the first current transfer branch are reliably switched off, the capacitors quickly build up direct voltage high enough to resist the system, and an energy absorption circuit limits the voltage of the capacitors. Thus, the size and cost of the capacitors are well controlled.

The invention relates to a ground electrode circuit grounding protective system of a high-voltage DC transmission system. The system is provided with two parallel ground electrode circuits respectively connected in series with a high-voltage DC breaker, sets an allowable range of current differences of two ground wires and an allowable range of the subtraction of the line current sum of the two ground wires from the line current difference of the two ground wires and then sequentially executes the following control program: (1), reading currents of the two ground wires; (2), judging and comparing whether an absolute value of the current difference of two ground wires is larger than the allowable range thereof, if the absolute value is not larger than the allowable range, returning to the step (1); if the absolute value is larger than the allowable range, (3) then, judging whether the subtraction of the line current sum of the two ground wires from the line current difference of the two ground wires is smaller than or equal to the allowable range; if the subtraction is smaller than or equal to the allowable range, returning to the step (1); and if the subtraction is not smaller than or equal to the allowable range, enabling the high-voltage DC breaker which is connected in series with the ground wire with larger line current to trip and terminate the program. The system can avoid the imbalance of the ground electrode circuits due to the failures of the ground electrode circuits and protects the caused DC transmission system to be closed down.

The invention discloses a direct current traction power supply system and a protective method, and utilizes direct current protective device outlet information and a short circuit fault mark value as a criterion to judge various direct current short circuit faults. When the short fault occurs, an alternating current incoming line breaker closest to a fault element is subjected to brake separating; if the sum of the fault mark values of the element, measured and computed after the brake separating, is more than or equal to 1, permanent fault is determined, the alternating current incoming line breakers of other traction substations in the whole line are subjected to brake separating, and related direct current isolation switches are subjected to brake separating to enable the alternating current incoming line breakers of the traction substation in the whole line to be subjected to switching on, so the power supply of the system can be restored; and if the sum of the fault mark values of the element is smaller than 1, the fault is instant, and related breakers are switched on for restoring the power supply of the system. The direct current traction power supply system and the protective method are capable of omitting the direct current breakers and saving investment, convenient to implement, suitable for carrying out new line construction or old line transformation in occasions where the lines are not very long (for example in 20m and less than 10 traction substations). When the line is overlong, the traction power supply system can be subjected to partition by a small amount of direct current breakers.

The invention relates to a full-solid-state direct-current circuit breaker of a direct-current power distribution network. The full-solid-state direct-current circuit breaker is characterized in that the direct-current circuit breaker is formed by connecting an auxiliary circuit breaker loop, a main circuit breaker loop and an energy absorption loop in parallel, and the auxiliary circuit breaker loop comprises a thyristor switch unit and a modularized full control device switch unit, and the thyristor switch unit and the modularized full control device switch unit are connected in series; the main circuit breaker loop comprises a plurality of press fit full control device switch units, a lightning arrester and a fuser, and a diode bridge type structure is adopted for two-way through flow; the energy absorption loop comprises at least one lightning arrester. The full-solid-state direct-current circuit breaker is novel in topology structure and comprehensive in function, the on-state loss is small in normal operation, the current state can be fast detected, faults can be effectively recognized, two-way current can be cut off in faults, the current turn-off grade is high, the fault removal speed is high, the voltage and energy absorption effect is good in the turn-off process, the rate of rise of fault current is effectively limited, and the series-connection valve banks of the main circuit breaker loop and the full control device of the auxiliary circuit breaker loop can be reliably protected.

A direct current circuit breaker includes main circuit for carrying a main-path current, and a transient circuit for carrying a transient-path current. The main circuit includes a first solid state switch and a main contactor. The first solid state switch is coupled in series with the main contactor. The transient circuit is coupled in parallel with the main circuit. The transient circuit includes an auxiliary contactor coupled in series with a second solid state switch. The second solid state switch closes when the main-path current exceeds a first threshold. The first solid state switch then opens. The main contactor opens when the main-path current falls below a second threshold. Then the second solid state switch opens. The auxiliary contactor opens when the transient-path current falls below the second threshold and after the second solid state switch opens.

The invention discloses a convertor station having direct current fault clearance capacity and a control method of the convertor station. The convertor station comprises a modularized multi-level convertor, a smoothing reactor, a fast shunt isolating switch, a fast on-off switch, a current transfer switch and a line discharge leading circuit. According to the convertor station, direct current faults can be cleared away quickly and effectively. Compared with a sub-module replacement scheme, the convertor station has the advantages that manufacturing cost is approximate or slightly high, and running loss is low and identical with that of the modularized multi-level convertor with a half-bridge sub-module; compared with a scheme that a direct current breaker is adopted, the convertor station has the advantage that manufacturing cost is greatly reduced, particularly in a multi-terminal direct current transmission system.

The invention relates to a series capacitor type high-voltage direct current breaker and a control method thereof. The breaker comprises direct current breaker units which are connected in series, and each direct current breaker unit comprises a change-over switch, a switching circuit and an energy consumption device which are connected in parallel. The change-over switch adopts a mechanical switch, and the switching circuit adopts a resistance capacitance branch circuit, and the energy consumption device adopts a lightning arrester. The high-voltage direct current breaker is connected with a control circuit, and the mechanical switch detects failure current and acts at the T1moment, and transfers the failure current into the resistance capacitance branch circuit. The failure current charges a capacitor, and controls switching-on and switching-off of the mechanical switch. Before the mechanical switch witches off at the T2 moment, charging voltage on two ends of the capacitor throughout is lower than arcing voltage at fractures of the mechanical switch. When the voltage on two ends of the capacitor reaches operation voltage of the lightning arrester, the control circuit controls the lightning arrester to act at the T3 moment so that energy can be released from the lightning arrester. According to the series capacitor type high-voltage direct current breaker and the control method thereof, the mechanical switch does not have electric arc, non-arc breaking off is realized, energy is released through utilization of the lightning arrester, quick extinguishing of the electric arc is realized, and the failure current is cut off.

The invention relates to a circuit breaker and a realization method thereof, and particularly relates to a high-voltage DC circuit breaker and a realization method thereof. The DC circuit breaker, based on a secondary current transferring principle, comprises a main branch, a current transferring branch and an energy absorption branch in parallel connection. The DC circuit breaker is serially connected in a DC system. The main branch comprises at least one high-speed mechanical switch K and at least one current transferring module comprising a fully-controlled device in serial connection. The current transferring branch is a bridge circuit formed by thyristor valves, inductors and capacitors. The energy absorption branch is formed by a non-linear resistor. The invention also provides a high-voltage DC circuit breaker realization method. The circuit breaker provided by the invention has a simple topological structure, the control is simple and convenient, used power electronic devices are mainly half-controlled thyristors, the technology is mature, realization is easy, the current breaking ability is large, a voltage-withstanding grade is high, the extension ability is strong, and the cost is greatly reduced.

The invention provides a hybrid type rapid direct current breaker, comprising: a main flow branch, a current transferring branch and an energy consumption branch. All are connected in parallel. The main flow branch comprises a rapid mechanical switch unit and a main branch sub-module unit. The two units are in series connection. The current transferring branch comprises valve module units in successive cascade connection with each valve module unit comprising a plurality of semiconductor modules in series connection. The energy consumption branch comprises energy consumption components in successive cascade connection. According to the invention, the design of the breaker structure is such a design featuring the electrical topology corresponding to modularization. This means that for the application requirement of different voltage grades, the structure can be expanded to do so. As the breaker adopts a single platform supporting structure, all functional units can be integrated onto the platform, therefore, making the equipment highly integrated, small in size, and strongly resistant to earthquakes. Highly reliable and flexible in structure, better electric compatibility can be achieved. With the breaker, it is possible to rapidly cut off the current in fault when the direct current system meets a fault.

The invention relates to a hybrid DC current breaker topological structure. The hybrid DC current breaker topological structure is structurally characterized by comprising three parallel branches, wherein the first branch comprises a first mechanical switch K1, a second mechanical switch K2 and a capacitor C; the first mechanical switch K1 and the second mechanical switch K2 are connected in series and the second mechanical switch K2 and the capacitor C are connected in parallel, so as to get continuity of the normal working current of a system; the second branch is a solid-state switch S which is composed of a plurality of IGBT modules connected in series, wherein each IGBT module comprises two IGBTs in reversed series connection and is used for realizing two-way cutoff of fault current; the third branch is an energy release branch consisting of multiple ZnO lightning arresters in series and parallel connection. The hybrid DC current breaker disclosed by the invention has the advantages of low loss, achievement of two-way rapid cutoff and guarantee of reliable continuity of the solid-state switch.

The invention discloses a current transfer device and method suitable for a hybrid DC breaker. The device comprises a precharging capacitor, a rapid-conduction switch, a primary-side coil and a secondary-side coil; and the precharging capacitor and the primary-side coil form an electric circuit through the rapid-conduction switch, and two ends of the secondary-side coil are taken as leading-out terminals as the device and then are connected to the hybrid DC breaker. When the hybrid DC breaker enables a current to be provided or be cut off, the current transfer device and method provided by the invention can guarantee a branch current of a mechanical switch to be reliably transferred to a branch of a solid DC breaker, and, finally, the current is provided or cut off by the solid DC breaker. Compared with the prior art, the current transfer device and method has the advantages of simple implementation and low cost, and can reduce operation loss of the hybrid DC breaker when normal operation is performed.

The invention relates to a multi-terminal MMC-HVDC (modular multi-level converter high voltage direct current) bipolar short-circuit fault current calculation method. The method includes the following steps that: 1) the equivalent capacitance, equivalent reactance and equivalent resistance of the fault equivalent circuit of a single-terminal MMC-HVDC system converter station are calculated; 2) the discharge current of the converter station which appears after the converter station is latched is calculated; 3) the initial solution of the discharge current of each converter station in a multi-terminal MMC-HVDC system under a condition that the discharge current of the converter station is not affected by other converter stations is calculated; 4) fault current actually passing through each direct-current line in the multi-terminal MMC-HVDC system is calculated; 5) the equivalent resistance and equivalent reactance of the actual fault equivalent circuit of the converter station at each terminal in the multi-terminal MMC-HVDC system are calculated; 6) the discharge current of the converter station at each terminal of the multi-terminal MMC-HVDC system is re-calculated; and 7) the step 4) to step 6) are repeated, and the discharge current value of the outlet of the converter station at each terminal of the multi-terminal MMC-HVDC system is calculated. The multi-terminal MMC-HVDC bipolar short-circuit fault current calculation method has high precision and speed and is of a certain guiding significance for direct current power grid planning and direct current circuit breaker selection.

The invention provides a bidirectional mechanical direct-current circuit breaker based on a commutation driving circuit and a control method of the bidirectional mechanical direct-current circuit breaker. The bidirectional mechanical direct-current circuit breaker comprises a current passage branch circuit, a commutation branch circuit and an energy-absorbing and voltage-limiting branch circuit, wherein the current passage branch circuit comprises one or a plurality of mechanical switches serially connected with one another; the commutation branch circuit consists of a high-voltage capacitor and a commutation driving circuit which are connected serially; the energy-absorbing and voltage-limiting branch circuit consists of a lightning arrester; and the current passage branch circuit, the commutation branch circuit and the energy-absorbing and voltage-limiting branch circuit are connected with one another in parallel. When bidirectional current requires to be switched on or switched off, current can be transferred to the commutation branch circuit at first from the current passage branch circuit, and then is transferred to the energy-absorbing and voltage-limiting branch circuit, and finally, switch-on and switch-off of the bidirectional current are realized. The bidirectional mechanical direct-current circuit breaker based on the commutation driving circuit has the advantages of low cost, simple structure and high reliability.

The invention provides a symmetrical bipolar MMC DC-side single-pole ground fault ride-through and recovery method. Through cooperation of a DC circuit breaker and a converter, DC fault current cut-off and power recovery are realized, and safe operation of the converter is protected. Through cooperation of active power and reactive power of the sound pole and the faulty pole, the active power deficiency of a converter station in the failure period is reduced. Rated reactive power is supplied to the grid, and therefore, the impact of a fault to an AC system is reduced. By actively controlling the common-mode components of the reference voltages of the upper and lower bridge arms of the converter, the risk brought to the safe operation of the system by excessive current surge stress of the converter due to reclosing failure is avoided. Based on the fact that a dual-pole short-circuit fault at the DC side of a symmetrical bipolar MMC can be regarded as a special case of single-pole ground faults of both positive and negative DC buses, the method of the invention can be used to handle a dual-pole short-circuit fault at the DC side of a symmetrical bipolar MMC.

A high voltage DC circuit breaker includes a semiconductor switching assembly in series with a mechanical switch. When the semiconductor switching assembly is switched off due to a current fault, a residual current flowing through arresters of the semiconductor switching assembly is switched off by the mechanical switch. A capacitor arranged parallel to the mechanical switch leads to passive resonance effects, which in turn induce current zero crossings in its arc. The current zero crossings allow for reliable extinguishing of the arc. The mechanical switch can be an AC circuit breaker.

The invention relates to a breaker of a direct current system, in particular to a semi-controlled passive injection current high voltage direct current breaker and a realization method thereof. The breaker comprises a high speed switch-IGBT1 (Insulated Gate Bipolar Translator1) module series branch, a non-linear resistor branch connected in parallel with the branch, and a bridge circuit consisting of power electronic devices, a capacitor, a reactor and a resistor. The breaker can charge an injection current capacitor directly from the running direct current system without an auxiliary circuit; with the adoption of a high speed mechanical switch, the advantage of low loss during normal breakover is kept; bidirectional current can be broken without an arc quickly; the breaker is novel in circuit topological structure, mature in technology, easy to realize, great in current breaking capability and high in withstand voltage level; and the cost is lowered greatly since the power electronic devices are mainly semi-controlled.

The invention discloses a solar parking shed capable of charging automobiles. The solar parking shed comprises a sun shield, a solar battery pack structure and a control system, wherein the sun shield is supported by a plurality of props, and the solar battery pack structure comprises a plurality of solar panels; the solar panels are connected with a photovoltaic array shunt box through wires; the photovoltaic array shunt box is connected with a photovoltaic system controller through a DC circuit breaker; the photovoltaic system controller is connected with a storage battery; the storage battery is connected with a plurality of charging piles capable of charging the automobiles orderly through an independent photovoltaic inverter and a dual-power change-over switch; the charging piles are connected with a cable of the urban electric network through a dual-power change-over switch; the solar electric power generation is parallel in the urban electric network; and the solar battery pack structure is also improved. The invention can be used for charging the parked automobiles and incorporate the excess electric energy into the urban electric network, and the electric energy of the urban electric network can be automatically supplied to the charging piles, thereby greatly increasing the utilization ratio of the electric energy.

The invention discloses a high-voltage DC breaker and a control method thereof. The high-voltage DC breaker comprises an on-state current branch, a breaking current branch, and a bridge branch. The on-state current branch is formed by a mechanical switch and a current transfer module provided with a fully-controlled device and guarantees low-on-state loss in a normal on state. The breaking current branch is formed by a nonlinear resistor and a fully-controlled device series valve group which are connected in parallel. The bridge branch comprises two bridge arms formed by four same commutation modules. Each commutation module is formed by an uncontrolled device series valve group and an inductor which are connected in series. The bridge branch enables the breaking current branch to be capable of breaking bidirectional bidirectional line current and reduces the number of fully-controlled devices and equipment cost.

The invention discloses a DC breaker topology structure and a DC control method and belongs to the field of power and electronic technologies. The DC breaker has a "T" type two-way symmetrical structure and comprises a first current path, a second current path and a third current path. A leading-out terminal a of the first current path is connected with an end of a DC power transmission and distribution system equivalent inductor L9. A middle leading-out terminal b of the first current path is connected with one parallel ends of the second current path and the third current path. A leading-out terminal c of the first current path is connected with a DC power transmission and distribution line. The other parallel ends of the second current path and the third current path are connected with the ground. The invention can effectively solve the problem of DC arc extinguishing, is flexible in structure and strong in expansibility, meets the requirements of current switching on, current switching off, voltage endurance, loss, energy absorption and the like under different voltage and current levels of the DC power transmission and distribution grid, and significantly reduces the equipment cost.

The invention a mixed type circuit breaker with a bidirectional disconnecting function and an on-off method therefor. The circuit breaker comprises a main current loop, a current transfer branch, an overvoltage limiting branch, an online monitoring system, a control system, a wire inlet end C1 and a wire outlet end C2; the main current loop, the current transfer branch and the overvoltage limiting branch are connected in parallel; and the negative electrode of a semi-control type power semiconductor device VD1 and the positive electrode of a semi-control type power semiconductor device VD3 are connected with one end of a high-speed mechanical switch fracture while the negative electrode of a semi-control type power semiconductor device VD2 and the positive electrode of a semi-control type power semiconductor device VD4 are connected with the other end of the high-speed mechanical switch fracture. The mixed type circuit breaker has the bidirectional conduction and disconnecting capability and can be applied to a bidirectional flow-through direct current power supply system.

The invention provides a direct current circuit breaker used for controlling on-off of a high-voltage direct current power transmission system. The direct current circuit breaker comprises a control system, a protection branch, and a through-flow circuit and an LC forced transfer circuit which are in parallel connection, wherein the through-flow circuit consists of a circuit breaker body and an electric power diode which are connected in series; the LC forced transfer circuit consists of a first pre-charging capacitor, a first inductor and a thyristor which are connected in series; the response time of the thyristor is shorten than that of the circuit breaker body; the protection branch is used for performing voltage clamping when the voltages at the two ends of the through-flow circuit and/or the LC forced transfer circuit are greater than or equal to a voltage set value; the control system is used for controlling the on-off of the through-flow circuit and the LC forced transfer circuit; and the control system is used for transmitting a conduction signal to the thyristor before the circuit breaker body is disconnected so as to enable the current passing through the through-flow circuit to be lower than or equal to a first current set value at the disconnecting moment of the circuit breaker body.

The invention provides a novel combined type DC breaker, comprising a transferring branch, an energy absorption branch, and at least two main branches and at least two auxiliary branches. The transferring branch is in parallel with the energy absorption branch. The main branch is corresponding to the auxiliary branch in a one-to-one manner. The main branch is connected to the DC outlet of a DC busin a high-voltage direct current (HVDC) transmission system. The auxiliary branch is in series with the transferring branch, and then is in parallel with the two ends of the main branch correspondingto the auxiliary branch. Compared with the prior art, the invention is advantageous in that the application economy performance of a high-voltage DC breaker in a flexible DC grid can be improved; theestablishment of the DC grid and the popularization and application of the mixed type DC breaker can be facilitated.

The invention belongs to the technical field of power system relay protection and particularly relates to a DC line relay protection method for a multi-terminal flexible medium-voltage DC power distribution system. The method comprises the steps of main protection and the backup protection. The main protection reflects an inter-electrode short-circuit fault of a DC line and a unipolar grounding fault of a small transition resistor, wherein a fault type and a fault interval are identified based on a current state matrix. The backup protection adopts the duration of the voltage imbalance as a starting criterion, so as to protect a judging fault interval of positive and negative current imbalance state matrixes at an installation part and isolate faults. The method determines the action signal of a DC breaker according to the switching-on/off signals of the main protection and the backup protection. The main protection only depends on the status signal values -1, 0 and 1 of two adjacent protection and transmission current elements, so that the requirement on a communication system is reduced. The backup protection judges the occurrence of a fault only based on the voltage, wherein the unbalanced current calculation is aiming at the positive current and the negative current of the same protection part. Therefore, the generation of errors due to the communication delay or the non-synchronized communication can be avoided.