CN115693634A - Self-healing direct current system with intelligent bus voltage loss compensation function and compensation method - Google Patents
Self-healing direct current system with intelligent bus voltage loss compensation function and compensation method Download PDFInfo
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Abstract
A self-healing direct-current system with an intelligent bus voltage loss compensation function and a compensation method are disclosed, wherein power supply direct-current buses KM1+, KM 1-in a 1# direct-current system and power supply direct-current buses KM2+, KM 2-in a 2# direct-current system are connected through a bus-coupled transfer switch 1ZK4, a bidirectional DC-DC compensator DC1 is further arranged between the power supply direct-current buses, the bidirectional DC-DC compensator DC1 is composed of three modules B1, B2 and B3 containing H bridges, and an isolation transformer T1 is arranged between the H bridges in the module B3. Through detecting both ends busbar voltage and switch behavior to timely compensate busbar voltage, when one of them section generating line appears falling the electricity and the bus allies oneself with the switch and fails normal work, still can have two-way DC-DC change over switch to act as the bus allies oneself with the switch function, supply power to the other end bus by one section generating line, through module B1-B3's coordination effect when compensating, make the generating line step up for slowly stepping up gradually, reduce the impact to the load, this direct current system is applicable to high power density, direct current system field high to the electric energy quality requirement.
Description
Technical Field
The invention relates to the technical field of direct current systems of transformer substations, in particular to a self-healing direct current system with an intelligent bus voltage loss compensation function and a compensation method.
Background
The direct current system of the transformer substation is used for example to ensure the continuous operation of power supply equipment, two sections of buses are usually arranged, buses at two ends are respectively supplied with power uninterruptedly by two chargers and a storage battery pack, when one section of bus fails and loses voltage, a bus coupler transfer switch between the buses at two ends is switched on, so that the bus which is not subjected to voltage loss provides power for the bus which is subjected to voltage loss, and the stable operation of loads of the buses at two ends is ensured.
In order to solve the above problems, a voltage loss compensation device may be used between the two end buses, for example, chinese patent document CN 211351821U describes a storage battery open circuit monitoring and voltage loss compensation device, an H-bridge circuit is provided between the two end buses, and an H-bridge between the two end buses is electrically isolated through a transformer mutual inductor, so that when one end bus loses voltage, voltage compensation is performed on the one end bus by the other end bus, thereby achieving electrical isolation, when compensation is performed, no direct hardware connection exists between the two end buses, a fault of the one end bus can be timely cut off from the other end bus by turning off a MOSFET tube, and safety is high.
When the buses at the two ends are respectively connected with one section of H bridge, the leakage inductance energy storage and discharge of the mutual inductor can cause high-voltage peak of the switch MOSFET, so that the application of the H bridge as DC-DC in a direct current system can only be suitable for small-sized substations, and when the direct current load of a large-sized substation is more, the MOSFET of the H bridge can bear larger voltage impact.
When the DC-DC converter current system is subjected to voltage loss compensation, the voltages of the bus pieces at two ends are compensated mutually, one section of bus directly supplies power to the other section of bus after voltage conversion during compensation, the voltage difference easily causes impact on loads and equipment, and meanwhile, the DC-DC converter is not interactive with the switching among the bus coupler switch and the circuit breaker, so that unified and coordinated compensation and power supply guarantee cannot be formed.
Disclosure of Invention
The invention aims to solve the technical problem of providing a self-healing direct current system with an intelligent bus voltage loss compensation function and a compensation method, which can form high-efficiency voltage compensation between two direct current buses of a high-power direct current system.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
self-healing direct current system with intelligent bus decompression compensation function, including two sets of interconnect's direct current system 1# and 2#, its characterized in that:
a power supply direct current bus KM1+ and KM 1-are arranged in the 1# direct current system;
a charger 1AD of a 1# direct current system is connected with a power supply direct current bus KM1+ and KM 1-through a direct current breaker 1ZK 1;
the 1# storage battery module is connected with a charger 1AD of the 1# direct current system through a direct current breaker 1ZK 2;
the 1# storage battery module is connected with a power supply direct current bus KM1+ and KM 1-through a direct current breaker 1ZK3,
a power supply direct current bus KM2+ and KM 2-are arranged in the 2# direct current system;
a charger 2AD of the 2# direct current system is connected with a power supply direct current bus KM2+ and KM 2-through a direct current breaker 2ZK 1;
the 2# storage battery module is connected with a charger 2AD of the 2# direct current system through a direct current breaker 2ZK 2;
the 2# storage battery module is connected with a power supply direct current bus KM2+ and KM 2-through a direct current breaker 2ZK3,
the power supply direct-current buses KM1 and KM 1-are connected with the power supply direct-current buses KM2 and KM 2-through a bus coupler change-over switch 1ZK4, a bidirectional DC-DC compensator DC1 is further arranged between the power supply direct-current buses KM1 and KM 1-and the direct-current buses KM2 and KM2-, and two ends of the bidirectional DC-DC compensator DC1 are respectively connected with a 1# direct-current bus and a 2# direct-current bus.
The bidirectional DC-DC compensator DC1 is controlled by a controller U1;
voltage detection devices 1DV3 and 2DV3 are respectively arranged on the power supply direct current buses KM1 & lt- & gt and the power supply direct current buses KM2 & lt- & gt and KM2 & lt- >
the voltage detection devices 1DV3 and 2DV3 are electrically connected with the input end of the controller U1;
the direct current circuit breakers 1ZK1-1ZK3, 2ZK1-2ZK3 and the bus coupler change-over switch 1ZK4 are electrically connected with the input end of the controller U1.
The bidirectional DC-DC compensator DC1 comprises three modules B1, B2 and B3 containing H bridges, an isolation transformer T1 is arranged between the H bridges in the module B3, one end of the H bridge of the module B1 is electrically connected with a power supply direct-current bus KM1+ and KM1-, the other end of the H bridge of the module B1 is electrically connected with one end of the H bridge of the module B2, the other end of the H bridge of the module B2 is electrically connected with the power supply direct-current bus KM1+ and KM1-, the positive and negative poles of the H bridge of the module B1 and the H bridge connecting end of the module B2 are connected with the input end of the H bridge in the module B3, and the output end of the H bridge in the module B3 is connected with the power supply direct-current bus KM2+ and KM 2-.
The H bridge in the module B3 consists of MOSFET tubes Q9-Q12, the two ends of the MOSFET tubes Q9 and Q10 are electrically connected with the H bridge of the module B1 and the positive and negative electrodes of the H bridge connecting end of the module B2, capacitors C6 and C7 which are connected in series are connected with the two ends of the MOSFET tubes Q9 and Q10 in parallel, one end of a primary coil of an isolation transformer T1 is connected with the middle points of the MOSFET tubes Q9 and Q10, and the other end of the primary coil is connected with the middle points of the capacitors C6 and C7;
the secondary coil of the isolation transformer T1 is divided into two sections by taking a middle point as a boundary, the upper end and the lower end of the secondary coil are respectively connected with MOSFET tubes Q11 and Q12 of the H bridge in series, the other ends of the MOSFET tubes Q11 and Q12 are connected in parallel and then electrically connected with a power supply direct current bus KM2+, and the middle point of the secondary coil of the isolation transformer T1 is electrically connected with the power supply direct current bus KM 2-.
The primary coil of the isolation transformer T1 is connected in series with the capacitor C8, and both ends of the primary coil connected in series with the capacitor C8 are electrically connected to the middle point of the MOSFET transistors Q9 and Q10 and the middle point of the capacitors C6 and C7, respectively.
And a capacitor C9 is arranged at the connecting end of the module B3 and the power supply direct current bus KM2+ and KM2-, and a capacitor C5 is arranged at the connecting end of the module B3 and the module B1/B2.
The H bridge in the module B1 consists of MOSFET (metal oxide semiconductor field effect transistor) tubes Q1-Q4, the MOSFET tubes Q1 and Q2 are connected in series, the MOSFET tubes Q3 and Q4 are connected in series, an inductor L1 is arranged between the middle points of the two series branches, and the two ends of the MOSFET tubes Q3 and Q4 are electrically connected with the module B2;
an H bridge in the module B2 consists of MOSFET (metal oxide semiconductor field effect transistor) tubes Q5-Q8, the MOSFET tubes Q5 and Q6 are connected in series, the MOSFET tubes Q7 and Q8 are connected in series, an inductor L2 is arranged between the middle points of the two series branches, and two ends of the MOSFET tubes Q7 and Q8 are electrically connected with the module B1;
and the grids S1 to S12 of the MOSFET tubes Q1 to Q12 are electrically connected with the output end of the controller U1.
The voltage loss compensation method of the self-healing direct current system with the intelligent bus voltage loss compensation function comprises the following specific steps:
step1, initializing parameters in the controller U1, including a voltage difference allowable threshold value U1, a compensation mode and compensation parameters;
switching on direct-current breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 of a Step2, a 1# direct-current system and a 2# direct-current system, and keeping a bus-tie change-over switch 1ZK4 disconnected;
step3, the controller U1 monitors voltage values detected by the voltage detection devices 1DV3 and 2DV3, states of the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 and states of the bus-coupled transfer switch 1ZK 4;
step4, when the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 are in a closing state and the bus tie change-over switch 1ZK4 is in an opening state, otherwise, the Step5 is entered, the voltage difference value between the two sections of buses detected by the voltage detection devices 1DV3 and 2DV3 is smaller than a voltage difference allowable threshold value U1, the voltage values of the two sections of buses are both in an allowable range, at the moment, the direct current system is in a normal working state, at the moment, the modules B1-B3 are in a stopping state, and the MOSFET tubes S1-S12 are in a closing state;
step4.1, when detecting that the voltage difference value between two sections of buses is greater than or equal to a voltage difference allowable threshold value U1 and the voltage of one section of bus is lower than the threshold value and exceeds allowable time, starting the bidirectional DC-DC compensator DC1, firstly judging the voltage between a power supply direct current bus KM1+ and KM 1-and a power supply direct current bus KM2+ and KM2-, and determining the input and output directions;
step4.2, when the voltage of the power supply direct current bus KM1+ and KM 1-is higher than that of the power supply direct current bus KM2+ and KM2-, the module B1 and the module B3 work, the power supply direct current bus KM1+ and KM 1-supply power to the power supply direct current bus KM2+ and KM2-, the duty ratio of the MOSFET control end Q1-Q4 of the module B1 is adjusted according to the voltage difference U between the power supply direct current bus KM1+ and the module B3, so that the voltage value input to the module B1 by the module B1 is adjusted, the power supply direct current bus KM2+ and KM 2-is gradually increased until the voltage is equal to that of the power supply direct current bus KM1+ and KM1-, and the module B1-are gradually withdrawn, the module B1 adjusts the duty ratio of the MOSFET control end Q1-Q4 to gradually reduce the input voltage, at the moment, when the power supply direct current bus KM2+ and KM 2-can be maintained in the set voltage range, the module B1 finally withdraws from the two ends and separately run, and if the power supply direct current bus KM2+ and KM 2-can not be maintained in the set voltage range, the direct current bus KM2+ and the direct current bus KM 2-can be continuously compensated;
step4.3, when the voltage of the power supply direct current bus KM1+ and KM 1-is lower than that of the power supply direct current bus KM2+ and KM2-, the module B2 and the module B3 work, the power supply direct current bus KM2+ and KM 2-supply power to the power supply direct current bus KM1+ and KM1-, the duty ratio of the MOSFET control end Q5-Q8 of the module B2 is adjusted according to the voltage difference U between the power supply direct current bus KM2+ and the module B3, so that the voltage value output by the module B2 to the power supply direct current bus KM1+ and KM 1-is adjusted, the voltage value input by the power supply direct current bus KM1+ and KM 1-is gradually increased until the voltage is equal to that of the power supply direct current bus KM2+ and KM2-, and then the module B2 enters a voltage stabilizing and gradually quits the mode, the module B2 adjusts the duty ratio of the MOSFET control end Q5-Q8 to gradually decrease the voltage input, and when the power supply direct current bus KM1+ and KM 1-can be maintained in the set voltage range, the module B2 finally quits, the two ends separately operate, and if the power supply direct current bus KM1+ and KM 1-can be continuously compensated to the direct current bus KM1+ and the power supply direct current bus KM 1-is maintained in the set voltage range;
step5, when one of the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 is completely disconnected, and the bus tie change-over switch 1ZK4 is in a disconnected state, immediately starting the bidirectional DC-DC compensator DC1, when the direct current circuit breaker 1ZK1-1ZK3 is disconnected, starting the modules B2 and B3, supplying power to the power supply direct current buses KM1+ and KM1 through the power supply direct current buses KM2+ and KM2-, and adjusting the voltage ratio between the input end of the module B3 and the output end of the module B2 to be 1;
when the direct current circuit breaker 2ZK1-2ZK3 is disconnected, the modules B1 and B3 are started, power is supplied to the power supply direct current buses KM2+ and KM 2-through the power supply direct current buses KM1+ and KM1-, and the voltage ratio between the input end of the module B1 and the output end of the module B3 is adjusted to 1.
A module B1 and a module B2 containing an H bridge are arranged on the side of a bus of one direct current system, a module B3 containing the combination of the H bridge and an isolation transformer T1 is arranged on the side of a bus of the other direct current system, the bidirectional compensation between two sets of direct current systems is realized by combining the fixed transformation ratio and the bidirectional flow of the isolation transformer T1 with the current flow direction control of the module B1/the module B2, a zero-current switch ZCS is realized by the module B3, and a zero-voltage switch ZVS is realized at the module B1/the module B2, so that high-voltage spikes of MOSFET tubes in the H bridge are avoided, high efficiency and high power density are realized at the module B1/the module B2, and the high-power module DC power supply system is suitable for being used in a high-power direct current power supply system.
The invention provides a self-healing direct current system with an intelligent bus voltage loss compensation function and a compensation method, which can timely compensate bus voltage by detecting the bus voltage at two ends and the working condition of a switch, when one section of bus is powered off and a bus-coupled switch cannot work normally, a bidirectional DC-DC change-over switch can also serve as the bus-coupled switch function, one section of bus supplies power to the other section of bus, and the bus voltage is slowly and gradually boosted by the coordination of modules B1-B3 during compensation, so that the impact on a load is reduced.
Drawings
The invention is further illustrated with reference to the following figures and examples:
FIG. 1 is a schematic circuit diagram of a DC system of the present invention;
FIG. 2 is a block diagram of a control structure of the bidirectional DC-DC compensator DC 1;
fig. 3 is a schematic diagram of the electrical connection of the controller U1.
Detailed Description
As shown in fig. 1-3, the self-healing dc system with the function of intelligent bus voltage loss compensation includes two sets of dc systems 1# and 2# connected to each other;
a power supply direct current bus KM1+ and KM 1-are arranged in the 1# direct current system;
a charger 1AD of a 1# direct current system is connected with a power supply direct current bus KM1+ and KM 1-through a direct current breaker 1ZK 1;
the 1# storage battery module is connected with a charger 1AD of the 1# direct current system through a direct current breaker 1ZK 2;
the 1# storage battery module is connected with a power supply direct current bus KM1+ and KM 1-through a direct current breaker 1ZK3,
a power supply direct current bus KM2+ and KM 2-is arranged in the 2# direct current system;
a charger 2AD of the 2# direct current system is connected with a power supply direct current bus KM2+ and KM 2-through a direct current breaker 2ZK 1;
the 2# storage battery module is connected with a charger 2AD of the 2# direct current system through a direct current breaker 2ZK 2;
the 2# storage battery module is connected with a power supply direct current bus KM2+ and KM 2-through a direct current breaker 2ZK3,
the power supply direct-current buses KM1 and KM 1-are connected with the power supply direct-current buses KM2 and KM 2-through a bus coupler change-over switch 1ZK4, a bidirectional DC-DC compensator DC1 is further arranged between the power supply direct-current buses KM1 and KM 1-and the direct-current buses KM2 and KM2-, and two ends of the bidirectional DC-DC compensator DC1 are respectively connected with a 1# direct-current bus and a 2# direct-current bus.
The bidirectional DC-DC compensator DC1 is controlled by a controller U1;
voltage detection devices 1DV3 and 2DV3 are respectively arranged on the power supply direct current buses KM1 & lt- & gt and the power supply direct current buses KM2 & lt- & gt and KM2 & lt- >
the voltage detection devices 1DV3 and 2DV3 are electrically connected to an input terminal of the controller U1.
The direct-current circuit breakers 1ZK1-1ZK3, 2ZK1-2ZK3 and the bus coupler change-over switch 1ZK4 are electrically connected with the input end of the controller U1.
The bidirectional DC-DC compensator DC1 comprises three modules B1, B2 and B3 containing H bridges, an isolation transformer T1 is arranged between the H bridges in the module B3, one end of the H bridge of the module B1 is electrically connected with power supply direct current buses KM1+ and KM1-, the other end of the H bridge of the module B1 is electrically connected with one end of the H bridge of the module B2, the other end of the H bridge of the module B2 is electrically connected with the power supply direct current buses KM1+ and KM1-, the positive and negative poles of the H bridge of the module B1 and the H bridge connecting end of the module B2 are connected with the H bridge input end in the module B3, and the H bridge output end in the module B3 is connected with the power supply direct current buses KM2+ and KM 2-.
Through an isolation transformer T1 in the module B3, the power supply direct current buses KM1+ and KM 1-and the power supply direct current buses KM2+ and KM 2-are electrically isolated, the current between the buses can be bidirectional current, the 1# direct current system can supply power to the 2# direct current system, and the 2# direct current system can also supply power to the 1# direct current system;
meanwhile, the H-bridge connection structure of the module B1/the module B2 can realize accurate voltage regulation through duty ratio regulation of H-bridge MOSFET tubes in the module B1 and the module B2, when the 1# direct current system supplies power to the 2# direct current system, the power supply direct current buses KM1+ and KM 1-are used as input ends of the module B1, power is provided for the power supply direct current buses KM2+ and KM 2-through the module B3, when the 2# direct current system supplies power to the 1# direct current system, the power supply direct current buses KM2+ and KM 2-are used as input ends of the module B3, and power is provided for the direct current buses KM1+ and KM 1-through the module B2.
The H bridge in the module B3 consists of MOSFET tubes Q9-Q12, the two ends of the MOSFET tubes Q9 and Q10 are electrically connected with the H bridge of the module B1 and the positive and negative electrodes of the H bridge connecting end of the module B2, capacitors C6 and C7 which are connected in series are connected with the two ends of the MOSFET tubes Q9 and Q10 in parallel, one end of a primary coil of an isolation transformer T1 is connected with the middle points of the MOSFET tubes Q9 and Q10, and the other end of the primary coil is connected with the middle points of the capacitors C6 and C7;
the secondary coil of the isolation transformer T1 is divided into two sections by taking the middle point as a boundary, the upper end and the lower end of the secondary coil are respectively connected with the MOSFET tubes Q11 and Q12 of the H bridge in series, the other ends of the MOSFET tubes Q11 and Q12 are electrically connected with the power supply direct current bus KM2+ after being connected in parallel, and the middle point of the secondary coil of the isolation transformer T1 is electrically connected with the power supply direct current bus KM 2-.
The isolation transformer T1 in the module B3 has the function of electrically isolating two ends of the bidirectional DC-DC compensator DC1, the primary coil and the secondary coil can be bidirectionally switched, so that the DC1 has bidirectional voltage conversion capability, current can bidirectionally flow, and meanwhile, the fixed transformation ratio of the primary coil and the secondary coil of the isolation transformer T1 is matched with the on-off matching of the MOSFET tubes Q9-Q12 to enable voltage lifting with fixed ratio to be provided.
The primary coil of the isolation transformer T1 is connected in series with the capacitor C8, and both ends of the primary coil connected in series with the capacitor C8 are electrically connected to the middle point of the MOSFET transistors Q9 and Q10 and the middle point of the capacitors C6 and C7, respectively.
The transformation ratio between the first section of the bus and the second section of the bus of the isolation transformer T1 is 1.
By adding a smaller capacitor C8 at the primary coil side, the self-resonant frequency of the capacitor C8 and the leakage inductance of the isolation transformer T1 can provide a zero current switch ZCS, namely, by using the inherent resonant frequency of the current at the primary coil side of the isolation transformer T1, the MOSFET of the module B3 can be switched at the zero crossing point of the resonant part of the MOSFET; when the resonant current reaches zero, Q9-Q12 are always switched on and off; specifically, in the operating mode of the module B3, taking the case of the 1# dc system to the 2# dc system as an example, when Q9 and Q11 are turned on, i.e., during the period from t1 to t2, the primary side resonant current I3 flows in a sine wave manner until it reaches the zero position, and then Q10 and Q12 are turned on, i.e., during the period from t2 to t3, and the primary side resonant current I3 still maintains the shape of a sine wave and flows in the opposite direction;
the switching losses of the above-mentioned bidirectional DC-DC compensator DC1 are close to zero, so that the switches within the modules B1-B3 can operate at very high switching frequencies, very high power densities can be achieved, and by implementing a complete zero-current switch ZCS on the secondary winding and a partial ZCS on the primary winding.
And a capacitor C9 is arranged at the connecting end of the module B3 and the power supply direct current bus KM2+ and KM2-, and a capacitor C5 is arranged at the connecting end of the module B3 and the module B1/B2.
The H bridge in the module B1 consists of MOSFET (metal oxide semiconductor field effect transistor) tubes Q1-Q4, the MOSFET tubes Q1 and Q2 are connected in series, the MOSFET tubes Q3 and Q4 are connected in series, an inductor L1 is arranged between the middle points of the two series branches, and the two ends of the MOSFET tubes Q3 and Q4 are electrically connected with the module B2;
an H bridge in the module B2 consists of MOSFET (metal oxide semiconductor field effect transistor) tubes Q5-Q8, the MOSFET tubes Q5 and Q6 are connected in series, the MOSFET tubes Q7 and Q8 are connected in series, an inductor L2 is arranged between the middle points of the two serial branches, and two ends of the MOSFET tubes Q7 and Q8 are electrically connected with the module B1;
the gates S1-S12 of the MOSFET transistors Q1-Q12 are electrically connected to the output of the controller U1.
A capacitor C1 is arranged at the connecting section of the module B1 and the power supply direct current bus KM1+ and KM1-, and a capacitor C3 is arranged at the connecting end between the module B1 and the module B3;
the connecting section of the module B2 and the power supply direct current bus KM1+ and KM 1-is provided with a capacitor C3, and the connecting end between the module B2 and the module B3 is provided with a capacitor C4.
The module B1/the module B2 can provide accurate voltage regulating and stabilizing functions, the B1 and the B2 have the same structure, and bidirectional compensation voltage and current are provided in a power supply system, so the current directions are opposite, the current directions are formed by the on-off matching of MOSFET (metal oxide semiconductor field effect transistor) tubes of an internal H bridge, when one section of bus supplies power to the bus at the other end, the voltage of the bus to be supplied can be stably increased through the duty ratio regulation of the module B1/the module B2, and the voltage cannot be directly increased to the voltage of the power supply bus, so that flexible voltage boosting can be realized, a load can obtain enough strain time, and current impact caused by sudden voltage boosting is reduced;
in the conversion process of the module B1/the module B2, the controller U1 can be placed in a zero-voltage switch lifting control mode to realize zero-voltage conversion, and high efficiency and high power density can be realized in the module B1/the module B2 due to the adoption of the zero-voltage switch ZVS.
As shown in fig. 1 and 2, in actual operation, the switches 1ZK1-1ZK3 of the 1# dc system and the switches 2ZK1-2ZK3 of the 2# dc system are in a closed state, the controller U1 detects the bus voltages at two ends through the voltage detection devices 1DV3 and 2DV3, if the voltage drop of one of the buses exceeds a threshold, the other bus is used as an input, the bus with the voltage drop exceeding the threshold is used as a receiving end, the current voltage value of the voltage-loss bus is used as an initial value through the accurate voltage regulation of the module B1/the module B2, and soft start boosting operation is performed, so that the bus voltages at two ends are equal and are in a qualified range;
when one set of direct current bus of 1# and 2# is totally under-voltage and the bus tie switch 1ZK4 is not switched on, the other set of direct current system can supply power through the bidirectional DC-DC compensator DC1, and the two sets of systems are electrically isolated.
The voltage loss compensation method of the self-healing direct current system with the intelligent bus voltage loss compensation function comprises the following specific steps:
step1, initializing parameters in the controller U1, including a voltage difference allowable threshold value U1, a compensation mode and compensation parameters;
switching on direct-current breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 of a Step2, a 1# direct-current system and a 2# direct-current system, and keeping a bus-tie change-over switch 1ZK4 disconnected;
step3, the controller U1 monitors the voltage values detected by the voltage detection devices 1DV3 and 2DV3, the states of the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 and the state of the bus-coupled transfer switch 1ZK 4;
step4, when the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 are in a closing state and the bus tie change-over switch 1ZK4 is in an opening state, otherwise, the bus tie change-over switch enters Step5, the voltage difference value between the two sections of buses detected by the voltage detection devices 1DV3 and 2DV3 is smaller than a voltage difference allowable threshold value U1, the voltage values of the two sections of buses are within an allowable range, the direct current system is in a normal working state, the modules B1-B3 are in a stopping state, and the MOSFET tubes S1-S12 are in a closing state;
step4.1, when detecting that the voltage difference value between two sections of buses is greater than or equal to a voltage difference allowable threshold value U1 and the voltage of one section of bus is lower than the threshold value and exceeds allowable time, starting the bidirectional DC-DC compensator DC1, firstly judging the voltage between a power supply direct current bus KM1+ and KM 1-and a power supply direct current bus KM2+ and KM2-, and determining the input and output directions;
step4.2, when the voltage of the power supply direct current bus KM1+ and KM 1-is higher than that of the power supply direct current bus KM2+ and KM2-, the module B1 and the module B3 work, the power supply direct current bus KM1+ and KM 1-supply power to the power supply direct current bus KM2+ and KM2-, the duty ratio of the MOSFET control end Q1-Q4 of the module B1 is adjusted according to the voltage difference U between the power supply direct current bus KM1+ and the module B3, so that the voltage value input to the module B1 by the module B1 is adjusted, the power supply direct current bus KM2+ and KM 2-is gradually increased until the voltage is equal to that of the power supply direct current bus KM1+ and KM1-, and the module B1-are gradually withdrawn, the module B1 adjusts the duty ratio of the MOSFET control end Q1-Q4 to gradually reduce the input voltage, at the moment, when the power supply direct current bus KM2+ and KM 2-can be maintained in the set voltage range, the module B1 finally withdraws from the two ends and separately run, and if the power supply direct current bus KM2+ and KM 2-can not be maintained in the set voltage range, the direct current bus KM2+ and the direct current bus KM 2-can be continuously compensated;
step4.3, when the voltage of the power supply direct current bus KM1+ and KM 1-is lower than that of the power supply direct current bus KM2+ and KM2-, the module B2 and the module B3 work, the power supply direct current bus KM2+ and KM 2-supply power to the power supply direct current bus KM1+ and KM1-, the duty ratio of the MOSFET control end Q5-Q8 of the module B2 is adjusted according to the voltage difference U between the power supply direct current bus KM2+ and the module B3, so that the voltage value output by the module B2 to the power supply direct current bus KM1+ and KM 1-is adjusted, the voltage value input by the power supply direct current bus KM1+ and KM 1-is gradually increased until the voltage is equal to that of the power supply direct current bus KM2+ and KM2-, and then the module B2 enters a voltage stabilizing and gradually quits the mode, the module B2 adjusts the duty ratio of the MOSFET control end Q5-Q8 to gradually decrease the voltage input, and when the power supply direct current bus KM1+ and KM 1-can be maintained in the set voltage range, the module B2 finally quits, the two ends separately operate, and if the power supply direct current bus KM1+ and KM 1-can be continuously compensated to the direct current bus KM1+ and the power supply direct current bus KM 1-is maintained in the set voltage range;
step5, when all the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 are disconnected, and the bus tie change-over switch 1ZK4 is in a disconnected state, immediately starting the bidirectional DC-DC compensator DC1, when the direct current circuit breakers 1ZK1-1ZK3 are disconnected, starting the modules B2 and B3, supplying power to the power supply direct current buses KM1+ and KM1 through the power supply direct current buses KM2+ and KM2-, and adjusting the voltage ratio between the input end of the module B3 and the output end of the module B2 to be 1;
when the direct current circuit breaker 2ZK1-2ZK3 is disconnected, the modules B1 and B3 are started, power is supplied to the power supply direct current buses KM2+ and KM 2-through the power supply direct current buses KM1+ and KM1-, and the voltage ratio between the input end of the module B1 and the output end of the module B3 is adjusted to 1.
Claims (8)
1. Self-healing direct current system with intelligent bus decompression compensation function, including two sets of interconnect's direct current system 1# and 2#, its characterized in that:
a power supply direct current bus KM1+ and KM 1-is arranged in the 1# direct current system;
a charger 1AD of a 1# direct current system is connected with a power supply direct current bus KM1+ and KM 1-through a direct current breaker 1ZK 1;
the 1# storage battery module is connected with a charger 1AD of the 1# direct current system through a direct current breaker 1ZK 2;
the 1# storage battery module is connected with a power supply direct current bus KM1+ and KM 1-through a direct current breaker 1ZK3,
a power supply direct current bus KM2+ and KM 2-is arranged in the 2# direct current system;
a charger 2AD of the 2# direct current system is connected with a power supply direct current bus KM2+ and KM 2-through a direct current breaker 2ZK 1;
the 2# storage battery module is connected with a charger 2AD of the 2# direct current system through a direct current breaker 2ZK 2;
the 2# storage battery module is connected with a power supply direct current bus KM2+ and KM 2-through a direct current breaker 2ZK3,
the power supply direct-current buses KM1 and KM 1-are connected with the power supply direct-current buses KM2 and KM 2-through a bus coupler change-over switch 1ZK4, a bidirectional DC-DC compensator DC1 is further arranged between the power supply direct-current buses KM1 and KM 1-and the direct-current buses KM2 and KM2-, and two ends of the bidirectional DC-DC compensator DC1 are respectively connected with a 1# direct-current bus and a 2# direct-current bus.
2. A self-healing DC system with intelligent bus voltage loss compensation function according to claim 1, wherein the bidirectional DC-DC compensator DC1 is controlled by a controller U1;
voltage detection devices 1DV3 and 2DV3 are respectively arranged on the power supply direct current buses KM1 & lt- & gt and the power supply direct current buses KM2 & lt- & gt and KM2 & lt- >
the voltage detection devices 1DV3 and 2DV3 are electrically connected with the input end of the controller U1;
the direct current circuit breakers 1ZK1-1ZK3, 2ZK1-2ZK3 and the bus coupler change-over switch 1ZK4 are electrically connected with the input end of the controller U1.
3. A self-healing DC system with an intelligent bus voltage loss compensation function according to claim 2, wherein the bidirectional DC-DC compensator DC1 is composed of three modules B1, B2 and B3 including H bridges, an isolation transformer T1 is provided between the H bridges in the module B3, one end of the H bridge of the module B1 is electrically connected to the DC supply bus KM1+ and KM1-, the other end of the H bridge of the module B1 is electrically connected to one end of the H bridge of the module B2, the other end of the H bridge of the module B2 is electrically connected to the DC supply bus KM1+ and KM1-, the H bridge of the module B1 and the positive and negative electrodes of the H bridge connection end of the module B2 are connected to the H bridge input end of the module B3, and the H bridge output end of the module B3 is connected to the DC supply bus KM2+ and KM 2-.
4. A self-healing dc system with intelligent bus voltage loss compensation function according to claim 3, wherein the H-bridge in the module B3 is composed of MOSFET tubes Q9-Q12, two ends of MOSFET tubes Q9 and Q10 are electrically connected to the positive and negative electrodes of the H-bridge of the module B1 and the H-bridge connection end of the module B2, capacitors C6 and C7 connected in series are connected in parallel to two ends of MOSFET tubes Q9 and Q10, one end of the primary coil of the isolation transformer T1 is connected to the middle point of MOSFET tubes Q9 and Q10, and the other end is connected to the middle point of capacitors C6 and C7;
the secondary coil of the isolation transformer T1 is divided into two sections by taking a middle point as a boundary, the upper end and the lower end of the secondary coil are respectively connected with MOSFET tubes Q11 and Q12 of the H bridge in series, the other ends of the MOSFET tubes Q11 and Q12 are connected in parallel and then electrically connected with a power supply direct current bus KM2+, and the middle point of the secondary coil of the isolation transformer T1 is electrically connected with the power supply direct current bus KM 2-.
5. A self-healing DC system with intelligent bus voltage loss compensation function according to claim 4, wherein the primary coil of the isolation transformer T1 is connected in series with a capacitor C8, and two ends of the primary coil connected in series with the capacitor C8 are respectively and electrically connected with the middle point of the MOSFET transistors Q9 and Q10 and the middle point of the capacitors C6 and C7.
6. A self-healing DC system with intelligent bus voltage loss compensation function according to claim 5, wherein a capacitor C9 is provided at the connection end of the module B3 and the power supply DC bus KM2+ and KM2-, and a capacitor C5 is provided at the connection end of the module B3 and the module B1/B2.
7. A self-healing direct-current system with an intelligent bus voltage loss compensation function according to claim 6, wherein an H bridge in the module B1 is composed of MOSFET tubes Q1-Q4, the MOSFET tubes Q1 and Q2 are connected in series, the MOSFET tubes Q3 and Q4 are connected in series, an inductor L1 is arranged between middle points of two series branches, and two ends of the MOSFET tubes Q3 and Q4 are electrically connected with the module B2;
an H bridge in the module B2 consists of MOSFET (metal oxide semiconductor field effect transistor) tubes Q5-Q8, the MOSFET tubes Q5 and Q6 are connected in series, the MOSFET tubes Q7 and Q8 are connected in series, an inductor L2 is arranged between the middle points of the two serial branches, and two ends of the MOSFET tubes Q7 and Q8 are electrically connected with the module B1;
and the grids S1 to S12 of the MOSFET tubes Q1 to Q12 are electrically connected with the output end of the controller U1.
8. The voltage loss compensation method of the self-healing direct current system with the intelligent bus voltage loss compensation function according to claim 7 is characterized by comprising the following specific steps:
step1, initializing parameters in the controller U1, including a voltage difference allowable threshold value U1, a compensation mode and compensation parameters;
switching on direct-current breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 of a Step2, a 1# direct-current system and a 2# direct-current system, and keeping a bus-tie change-over switch 1ZK4 disconnected;
step3, the controller U1 monitors the voltage values detected by the voltage detection devices 1DV3 and 2DV3, the states of the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 and the state of the bus-coupled transfer switch 1ZK 4;
step4, when the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 are in a closing state and the bus tie change-over switch 1ZK4 is in an opening state, otherwise, the Step5 is entered, the voltage difference value between the two sections of buses detected by the voltage detection devices 1DV3 and 2DV3 is smaller than a voltage difference allowable threshold value U1, the voltage values of the two sections of buses are both in an allowable range, at the moment, the direct current system is in a normal working state, at the moment, the modules B1-B3 are in a stopping state, and the MOSFET tubes S1-S12 are in a closing state;
step4.1, when the voltage difference value between two sections of buses is detected to be more than or equal to a voltage difference allowable threshold value U1 and the voltage of one section of bus is lower than the threshold value and exceeds allowable time, starting the bidirectional DC-DC compensator DC1, firstly judging the voltage between a power supply direct current bus KM1+ and a power supply direct current bus KM 1-and a power supply direct current bus KM2+ and a power supply direct current bus KM 2-and determining the input and output directions;
step4.2, when the voltage of the power supply direct current bus KM1+ and KM 1-is higher than that of the power supply direct current bus KM2+ and KM2-, the module B1 and the module B3 work, the power supply direct current bus KM1+ and KM 1-supplies power to the power supply direct current bus KM2+ and KM2-, the duty ratio of the MOSFET tube control end Q1-Q4 of the module B1 is adjusted according to the voltage difference U between the two, so as to adjust the voltage value input by the module B1 to the module B3, and gradually increase the power supply direct current bus KM2+ and KM 2-until the voltage is equal to that of the power supply direct current bus KM1+ and KM1-, and then the module B1 enters a voltage stabilization mode and gradually exits, the module B1 adjusts the duty ratio of the MOSFET tube control end Q1-Q4 to gradually decrease the input voltage, at this time, when the power supply direct current bus KM2+ and KM 2-can be maintained in the set voltage range, the module B1 finally exits, and both ends separately operate, and if the power supply direct current bus KM2+ and KM 2-cannot be maintained in the set voltage range, the module B1 + and KM2+ and compensate the direct current bus KM 2-again;
step4.3, when the voltage of the power supply direct current bus KM1+ and KM 1-is lower than that of the power supply direct current bus KM2+ and KM2-, the module B2 and the module B3 operate, the power supply direct current bus KM2+ and KM 2-supplies power to the power supply direct current bus KM1+ and KM1-, the duty ratio of the MOSFET tube control end Q5-Q8 of the module B2 is adjusted according to the voltage difference U between the two, so as to adjust the voltage value output by the module B2 to the power supply direct current bus KM1+ and KM1-, and realize the gradual increase of the power supply direct current bus KM1+ and KM 1-until the voltage is equal to that of the power supply direct current bus KM2+ and KM2-, then the module B2 enters a voltage stabilizing and gradually quitting mode, the module B2 adjusts the duty ratio of the MOSFET tube control end Q5-Q8 to gradually decrease the voltage input thereto, at this time, when the power supply direct current bus KM1+ and KM 1-can be maintained within the set voltage range, the module B2 finally operates with the two ends separated, and if the power supply direct current bus KM1+ and KM 1-is not maintained within the set voltage range of the power supply direct current bus KM1+ and KM 1-is continuously compensated;
step5, when one of the direct current circuit breakers 1ZK1-1ZK3 and 2ZK1-2ZK3 is completely disconnected, and the bus tie change-over switch 1ZK4 is in a disconnected state, immediately starting the bidirectional DC-DC compensator DC1, when the direct current circuit breaker 1ZK1-1ZK3 is disconnected, starting the modules B2 and B3, supplying power to the power supply direct current buses KM1+ and KM1 through the power supply direct current buses KM2+ and KM2-, and adjusting the voltage ratio between the input end of the module B3 and the output end of the module B2 to be 1;
when the direct current circuit breaker 2ZK1-2ZK3 is disconnected, the modules B1 and B3 are started, power is supplied to the power supply direct current buses KM2+ and KM 2-through the power supply direct current buses KM1+ and KM1-, and the voltage ratio between the input end of the module B1 and the output end of the module B3 is adjusted to 1.
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| CN202211326544.8A CN115693634B (en) | 2022-10-27 | 2022-10-27 | Self-healing direct current system with intelligent bus voltage loss compensation function and compensation method |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN211351821U (en) * | 2019-10-30 | 2020-08-25 | 武汉市豪迈电力自动化技术有限责任公司 | Storage battery pack open circuit monitoring and voltage loss compensation device |
| CN216720997U (en) * | 2021-08-20 | 2022-06-10 | 云南电网有限责任公司保山供电局 | Bus voltage loss protection system |
| CN115714370A (en) * | 2022-10-27 | 2023-02-24 | 国网湖北省电力有限公司宜昌供电公司 | Self-healing direct current system with intelligent bus voltage loss compensation function |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN211351821U (en) * | 2019-10-30 | 2020-08-25 | 武汉市豪迈电力自动化技术有限责任公司 | Storage battery pack open circuit monitoring and voltage loss compensation device |
| CN216720997U (en) * | 2021-08-20 | 2022-06-10 | 云南电网有限责任公司保山供电局 | Bus voltage loss protection system |
| CN115714370A (en) * | 2022-10-27 | 2023-02-24 | 国网湖北省电力有限公司宜昌供电公司 | Self-healing direct current system with intelligent bus voltage loss compensation function |
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