CN115693634B - 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
The self-healing type direct current system with the intelligent bus voltage loss compensation function and the compensation method thereof are characterized in that power supply direct current buses KM1+, KM 1-in the 1# direct current system and power supply direct current buses KM2+, KM 2-in the 2# direct current system are connected through a bus change-over 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. The bus voltage compensation device has the advantages that the bus voltage at two ends and the working condition of the switch are detected, so that the bus voltage is compensated timely, when one section of bus is powered down and the bus switch fails to work normally, the bidirectional DC-DC conversion switch can serve as the bus switch function, one section of bus supplies power to the other section of bus, and the bus is boosted slowly and gradually under the coordination of the modules B1-B3 during compensation, so that the impact on loads is reduced.
Description
Technical Field
The invention relates to the technical field of direct current systems of 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 as an example to ensure continuous operation of power supply equipment, two sections of buses are usually arranged, the two sections of buses are respectively supplied with power uninterruptedly by two chargers and a storage battery, when one section of buses fails and loses voltage, a bus-to-bus change-over switch between the two sections of buses is switched on, so that the buses which are not in voltage loss provide power for the buses which are in voltage loss, and stable operation of loads of the two sections of buses is ensured.
In order to solve the above problem, a voltage loss compensation device is adopted between 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 arranged between two end buses, and an H bridge between two end buses is electrically isolated through a transformer mutual inductance coil, so that when one end bus loses voltage, the other end bus compensates voltage, and electrical isolation is realized, when compensation is performed, no direct hardware connection is arranged between the two end buses, and the fault of one end bus can be timely cut off from the other end bus through the turn-off of a MOSFET tube, so that the 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 the discharge of the mutual inductance coil can cause the high voltage peak of the switching MOSFET, so that the application of the H bridge as DC-DC in a DC system can only be applied to a small-sized transformer station, and when the DC load of a large-sized transformer station 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 bus parts at two ends are mutually compensated, one section of bus is directly used for supplying power to the other section of bus after voltage conversion during compensation, the voltage difference easily impacts loads and equipment, meanwhile, the DC-DC converter is not interacted with switching between a bus-bar switch and a circuit breaker, and 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 for two direct current buses of a high-power direct current system.
In order to solve the technical problems, the invention adopts the following technical scheme:
self-healing direct current system with intelligent busbar decompression compensation function, including two sets of interconnect's direct current system 1# and 2#, its characterized in that:
A power supply direct current busbar KM1+ and KM 1-are arranged in the 1# direct current system;
The charger 1AD of the No. 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 a 1# direct current system through a direct current breaker 1ZK 2;
the No. 1 storage battery module is connected with power supply DC buses KM1+, KM1-through a DC breaker 1ZK3,
A power supply direct current busbar KM2+ and KM 2-are arranged in the 2# direct current system;
The charger 2AD of the No. 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 No. 2 storage battery module is connected with a charger 2AD of a No. 2 direct current system through a direct current breaker 2ZK 2;
the No. 2 storage battery module is connected with the power supply DC buses KM2+, KM2-through a DC breaker 2ZK3,
The power supply direct current buses KM1+, KM 1-and the power supply direct current buses KM2+, KM 2-are connected through a bus transfer switch 1ZK4, a bidirectional DC-DC compensator DC1 is further arranged between the power supply direct current buses KM1+, KM 1-and the direct current buses KM2+, 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+, KM1-and the power supply direct current buses KM2+, KM2-;
the voltage detection devices 1DV3 and 2DV3 are electrically connected with the input end of the controller U1;
the direct current breakers 1ZK1-1ZK3, 2ZK1-2ZK3 and the bus-tie transfer switch 1ZK4 are electrically connected with the input end of the controller U1.
The bidirectional DC-DC compensator DC1 is composed of 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 DC bus KM1+, 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 DC bus KM1+, KM1-, the positive and negative electrodes 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 DC buses KM2+, KM 2-.
The H bridge in the module B3 consists of MOSFET transistors Q9-Q12, two ends of the MOSFET transistors Q9 and Q10 are electrically connected with the H bridge of the module B1 and the anode and cathode of the H bridge connecting end of the module B2, capacitors C6 and C7 connected in series are connected with two ends of the MOSFET transistors Q9 and Q10 in parallel, one end of a primary coil of the isolation transformer T1 is connected with the middle point of the MOSFET transistors Q9 and Q10, and the other end of the primary coil of the isolation transformer T1 is connected with the middle point 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 an H bridge in series, the other ends of the MOSFET tubes Q11 and Q12 are connected in parallel and then are 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 KM2-.
The primary winding of the isolation transformer T1 is connected in series with the capacitor C8, and both ends of the primary winding connected in series with the capacitor C8 are electrically connected to the intermediate points of the MOSFET transistors Q9 and Q10 and the intermediate points of the capacitors C6 and C7, respectively.
The connection end of the module B3 and the power supply DC buses KM2+, KM 2-is provided with a capacitor C9, and the connection end of the module B3 and the module B1/B2 is provided with a capacitor C5.
The H bridge in the module B1 is composed of MOSFET transistors Q1-Q4, the MOSFET transistors Q1 and Q2 are connected in series, the MOSFET transistors Q3 and Q4 are connected in series, an inductor L1 is arranged between the middle points of the two series branches, and two ends of the MOSFET transistors Q3 and Q4 are electrically connected with the module B2;
The H bridge in the module B2 consists of MOSFET (metal-oxide-semiconductor field effect transistor) transistors Q5-Q8, the MOSFET transistors Q5 and Q6 are connected in series, the MOSFET transistors 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 transistors Q7 and Q8 are electrically connected with the module B1;
The gates S1-S12 of the MOSFET transistors Q1-Q12 are electrically connected with the output end of the controller U1.
The voltage loss compensation method for 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 U1, a compensation mode and compensation parameters;
The direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 of the Step2, the 1# direct current system and the 2# direct current system are switched on, and the bus-tie transfer switch 1ZK4 is kept off;
Step3, the controller U1 monitors the voltage values detected by the voltage detection devices 1DV3 and 2DV3, the states of the direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 and the states of the bus-tie transfer switch 1ZK 4;
Step4, when the direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 are in a closing state, the bus-bar transfer switch 1ZK4 is in an opening state, otherwise, step5 is entered, the voltage difference between two sections of buses detected by the voltage detection devices 1DV3 and 2DV3 is smaller than a voltage difference allowable threshold U1, the voltage values of the two sections of buses are 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 an off state;
Step4.1, when the voltage difference between two sections of buses is detected to be greater than or equal to a voltage difference allowable threshold U1, and the voltage of one section of bus is lower than the threshold and exceeds the allowable time, starting the bidirectional DC-DC compensator DC1, firstly judging the voltage between the power supply DC buses KM1+, KM 1-and the power supply DC buses KM2+ and KM2-and determining the input and output directions;
when the voltage of the power supply direct current buses KM1+, KM 1-is higher than that of the power supply direct current buses KM2+, KM2-, the module B1 and the module B3 work, the power supply direct current buses KM2+, KM 2-are supplied with power by the power supply direct current buses KM1+, KM1-, the duty ratio of the MOSFET tube control ends Q1-Q4 of the module B1 is regulated according to the voltage difference U between the power supply direct current buses KM1+, KM 1-and the module B1, the voltage value input by the module B1 to the module B3 is regulated, the voltage of the power supply direct current buses KM2+, KM 2-is gradually increased until the voltage is equal to that of the power supply direct current buses KM1+, KM 1-and then the module B1 enters a voltage stabilizing and gradually quitting mode, the voltage input by the module B1 regulates the duty ratio of the MOSFET tube control ends Q1-Q4 to gradually decrease, at the moment, when the power supply direct current buses KM2+, KM 2-can be maintained in a set voltage range, the two-end buses are separated to operate, and if the power supply direct current buses KM2+, KM 2-cannot be maintained in a set voltage range, the module B1 continuously regulates the voltage to be regulated to the power supply direct current buses 2-and compensates;
When the voltage of the power supply direct current buses KM1+, KM 1-is lower than the voltage of the power supply direct current buses KM2+, KM2-, the module B2 and the module B3 work, the power supply direct current buses KM2+, KM 2-supply power to the power supply direct current buses KM1+, KM 1-according to the voltage difference U between the power supply direct current buses KM1+, KM 1-and the module B2, the MOSFET control ends Q5-Q8 of the module B2 are regulated according to the duty ratio, so that the voltage value output by the module B2 to the power supply direct current buses KM1+, KM 1-is regulated, the gradual rising of the power supply direct current buses KM1+, KM 1-is realized until the voltage is equal to the voltage of the power supply direct current buses KM2+, KM2-, then the module B2 enters a voltage stabilizing and gradually exits the mode, the voltage input by the module B2 is gradually reduced, when the power supply direct current buses KM1+, KM 1-can be maintained in a set voltage range, the two-end buses are separated, and if the power supply direct current buses KM1+, KM 1-cannot be maintained in the set voltage range, the voltage is regulated to the module B2, and the power supply direct current buses 1-are continuously compensated;
Step5, when one group of the direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 is completely disconnected, and the bus transfer switch 1ZK4 is in a disconnected state, the bidirectional DC-DC compensator DC1 is immediately started, when the direct current breakers 1ZK 1-1 ZK3 are disconnected, the modules B2 and B3 are started, power is supplied to the power supply direct current buses KM2+, KM 2-by the power supply direct current buses KM1+, KM1-, and the voltage ratio between the input end of the module B3 and the output end of the module B2 is adjusted to be 1:1;
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 KM2-by 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 be 1:1.
The module B1 and the module B2 containing the H bridge are arranged on the bus side of one direct current system, the module B3 containing the combination of the H bridge and the isolation transformer T1 is arranged on the bus side of the other direct current system, the fixed transformation ratio of the isolation transformer T1 and the bidirectional flow thereof are combined with the current flow direction control of the module B1/the module B2, the bidirectional compensation between the two direct current systems is realized, the zero current switch ZCS is realized by the module B3, the zero voltage switch ZVS is realized at the module B1/the module B2, the high voltage peak of MOSFET tubes in the H bridge is avoided, the high efficiency and the high power density are realized at the module B1/the module B2, and the high-power direct current power supply system is suitable for being used.
According to the self-healing direct current system with the intelligent bus voltage loss compensation function and the compensation method, the bus voltage at two ends and the working condition of the switch are detected, so that the bus voltage is timely compensated, when one section of bus is powered down and the bus switch fails to work normally, the bidirectional DC-DC conversion switch can serve as the bus switch function, one section of bus supplies power to the other section of bus, and the modules B1-B3 are used for coordination during compensation, so that the bus is boosted slowly and gradually, the impact on loads is reduced, and the direct current system is suitable for the field of direct current systems with high power density and high electric energy quality requirements.
Drawings
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
FIG. 1 is a schematic diagram of a DC system circuit of the present invention;
FIG. 2 is a control structure composition diagram of a bidirectional DC-DC compensator DC 1;
fig. 3 is a schematic diagram of electrical connection of the controller U1.
Detailed Description
As shown in fig. 1-3, the self-healing direct current system with the intelligent bus voltage loss compensation function comprises two sets of direct current systems 1# and 2# which are connected with each other;
A power supply direct current busbar KM1+ and KM 1-are arranged in the 1# direct current system;
The charger 1AD of the No. 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 a 1# direct current system through a direct current breaker 1ZK 2;
the No. 1 storage battery module is connected with power supply DC buses KM1+, KM1-through a DC breaker 1ZK3,
A power supply direct current busbar KM2+ and KM 2-are arranged in the 2# direct current system;
The charger 2AD of the No. 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 No. 2 storage battery module is connected with a charger 2AD of a No. 2 direct current system through a direct current breaker 2ZK 2;
the No. 2 storage battery module is connected with the power supply DC buses KM2+, KM2-through a DC breaker 2ZK3,
The power supply direct current buses KM1+, KM 1-and the power supply direct current buses KM2+, KM 2-are connected through a bus transfer switch 1ZK4, a bidirectional DC-DC compensator DC1 is further arranged between the power supply direct current buses KM1+, KM 1-and the direct current buses KM2+, 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+, KM1-and the power supply direct current buses KM2+, KM2-;
The voltage detection devices 1DV3 and 2DV3 are electrically connected to an input of the controller U1.
The direct current breakers 1ZK1-1ZK3, 2ZK1-2ZK3 and the bus-tie transfer switch 1ZK4 are electrically connected with the input end of the controller U1.
The bidirectional DC-DC compensator DC1 is composed of 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 DC bus KM1+, 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 DC bus KM1+, KM1-, the positive and negative electrodes 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 DC buses KM2+, KM 2-.
Through an isolation transformer T1 in the module B3, electric isolation is realized between the power supply DC buses KM1+, KM1-and the power supply DC buses KM2+, KM2-, current between the buses can be bidirectional current, a 1# DC system can supply power to a 2# DC system, and a 2# DC system can also supply power to the 1# DC system;
Meanwhile, the H bridge connection structure of the module B1/the module B2 can realize accurate voltage regulation through the duty ratio adjustment of H bridge MOSFET tubes inside the module B1/the module B2, when the 1# direct current system supplies power to the 2# direct current system, the power supply direct current buses KM1+, KM 1-serve as the input end of the module B1, the module B3 supplies power to the power supply direct current buses KM2+, KM2-, and when the 2# direct current system supplies power to the 1# direct current system, the power supply direct current buses KM2+, KM 2-serve as the input end of the module B3, and the module B2 supplies power to the direct current buses KM1+, KM 1-.
The H bridge in the module B3 consists of MOSFET transistors Q9-Q12, two ends of the MOSFET transistors Q9 and Q10 are electrically connected with the H bridge of the module B1 and the anode and cathode of the H bridge connecting end of the module B2, capacitors C6 and C7 connected in series are connected with two ends of the MOSFET transistors Q9 and Q10 in parallel, one end of a primary coil of the isolation transformer T1 is connected with the middle point of the MOSFET transistors Q9 and Q10, and the other end of the primary coil of the isolation transformer T1 is connected with the middle point 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 an H bridge in series, the other ends of the MOSFET tubes Q11 and Q12 are connected in parallel and then are 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 KM2-.
The isolation transformer T1 in the module B3 has the function of electrically isolating two ends of the bidirectional DC-DC compensator DC1, and the primary coil and the secondary coil can be converted in a bidirectional manner, so that the DC1 has bidirectional voltage conversion capability, current can flow in a bidirectional manner, 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 cooperation of the MOSFET transistors Q9-Q12, so that voltage rise and fall with fixed ratio are provided.
The primary winding of the isolation transformer T1 is connected in series with the capacitor C8, and both ends of the primary winding connected in series with the capacitor C8 are electrically connected to the intermediate points of the MOSFET transistors Q9 and Q10 and the intermediate points of the capacitors C6 and C7, respectively.
The transformation ratio between the first section bus and the second section bus of the isolation transformer T1 is 1:2, so that the voltage of two sides can be equal through the secondary side intermediate point connection structure.
By adding a smaller capacitor C8 on the primary coil side, the self-resonant frequency of the capacitor C8 can provide zero-current switching ZCS with the leakage inductance of the isolation transformer T1, namely, the MOSFET of the module B3 can be switched at the zero-crossing point of the resonant part by utilizing the inherent resonant frequency of the current on the primary coil side of the isolation transformer T1; when the resonance current reaches zero, Q9-Q12 will be always on and off; specifically, in the operation mode of the module B3, taking the 1# 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 the form of a sine wave until it reaches the zero position, after which 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 the sine wave and flows in the opposite direction;
The switching losses of the bidirectional DC-DC compensator DC1 described above are close to zero, so that the switches in 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 switching ZCS on the secondary coil and a partial ZCS on the primary coil.
The connection end of the module B3 and the power supply DC buses KM2+, KM 2-is provided with a capacitor C9, and the connection end of the module B3 and the module B1/B2 is provided with a capacitor C5.
The H bridge in the module B1 is composed of MOSFET transistors Q1-Q4, the MOSFET transistors Q1 and Q2 are connected in series, the MOSFET transistors Q3 and Q4 are connected in series, an inductor L1 is arranged between the middle points of the two series branches, and two ends of the MOSFET transistors Q3 and Q4 are electrically connected with the module B2;
The H bridge in the module B2 consists of MOSFET (metal-oxide-semiconductor field effect transistor) transistors Q5-Q8, the MOSFET transistors Q5 and Q6 are connected in series, the MOSFET transistors 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 transistors 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.
The connecting section of the module B1 and the power supply direct current buses KM1+, KM 1-is provided with a capacitor C1, and the connecting end between the module B1 and the module B3 is provided with a capacitor C2;
The connecting section of the module B2 and the power supply direct current buses KM1+, 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/module B2 can provide accurate voltage regulation and stabilization functions, the module B1 and the module B2 have the same structure, bidirectional compensation voltage and current are provided in a power supply system, so that the current directions are opposite, the current directions are formed by the on-off matching of MOSFET 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 adjustment of the module B1/module B2, and the voltage of the bus to be supplied cannot be directly increased to the voltage of the bus to be supplied, so that flexible voltage increase can be realized, the load can obtain enough strain time, and current impact caused by sudden voltage increase 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# direct current system and the switches 2ZK1-2ZK3 of the 2# direct current system are in a closed state, the controller U1 detects the voltages of the buses at two ends through the voltage detection devices 1DV3 and 2DV3, if one section of bus voltage drops beyond a threshold value, the other section of bus is taken as an input, the bus with the voltage exceeding the threshold value is taken as a receiving end, the accurate voltage regulation is performed through the modules B1/B2, the current voltage value of the bus with the voltage being lost is taken as a starting value, and the soft start boosting operation is performed, so that the voltages of the buses at two ends are equal and are within a qualified range;
When one set of direct current buses in the 1# and the 2# is completely out of voltage, and the bus-connected 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 for 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 U1, a compensation mode and compensation parameters;
The direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 of the Step2, the 1# direct current system and the 2# direct current system are switched on, and the bus-tie transfer switch 1ZK4 is kept off;
Step3, the controller U1 monitors the voltage values detected by the voltage detection devices 1DV3 and 2DV3, the states of the direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 and the states of the bus-tie transfer switch 1ZK 4;
Step4, when the direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 are in a closing state, the bus-bar transfer switch 1ZK4 is in an opening state, otherwise, step5 is entered, the voltage difference between two sections of buses detected by the voltage detection devices 1DV3 and 2DV3 is smaller than a voltage difference allowable threshold U1, the voltage values of the two sections of buses are 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 an off state;
Step4.1, when the voltage difference between two sections of buses is detected to be greater than or equal to a voltage difference allowable threshold U1, and the voltage of one section of bus is lower than the threshold and exceeds the allowable time, starting the bidirectional DC-DC compensator DC1, firstly judging the voltage between the power supply DC buses KM1+, KM 1-and the power supply DC buses KM2+ and KM2-and determining the input and output directions;
when the voltage of the power supply direct current buses KM1+, KM 1-is higher than that of the power supply direct current buses KM2+, KM2-, the module B1 and the module B3 work, the power supply direct current buses KM2+, KM 2-are supplied with power by the power supply direct current buses KM1+, KM1-, the duty ratio of the MOSFET tube control ends Q1-Q4 of the module B1 is regulated according to the voltage difference U between the power supply direct current buses KM1+, KM 1-and the module B1, the voltage value input by the module B1 to the module B3 is regulated, the voltage of the power supply direct current buses KM2+, KM 2-is gradually increased until the voltage is equal to that of the power supply direct current buses KM1+, KM 1-and then the module B1 enters a voltage stabilizing and gradually quitting mode, the voltage input by the module B1 regulates the duty ratio of the MOSFET tube control ends Q1-Q4 to gradually decrease, at the moment, when the power supply direct current buses KM2+, KM 2-can be maintained in a set voltage range, the two-end buses are separated to operate, and if the power supply direct current buses KM2+, KM 2-cannot be maintained in a set voltage range, the module B1 continuously regulates the voltage to be regulated to the power supply direct current buses 2-and compensates;
When the voltage of the power supply direct current buses KM1+, KM 1-is lower than the voltage of the power supply direct current buses KM2+, KM2-, the module B2 and the module B3 work, the power supply direct current buses KM2+, KM 2-supply power to the power supply direct current buses KM1+, KM 1-according to the voltage difference U between the power supply direct current buses KM1+, KM 1-and the module B2, the MOSFET control ends Q5-Q8 of the module B2 are regulated according to the duty ratio, so that the voltage value output by the module B2 to the power supply direct current buses KM1+, KM 1-is regulated, the gradual rising of the power supply direct current buses KM1+, KM 1-is realized until the voltage is equal to the voltage of the power supply direct current buses KM2+, KM2-, then the module B2 enters a voltage stabilizing and gradually exits the mode, the voltage input by the module B2 is gradually reduced, when the power supply direct current buses KM1+, KM 1-can be maintained in a set voltage range, the two-end buses are separated, and if the power supply direct current buses KM1+, KM 1-cannot be maintained in the set voltage range, the voltage is regulated to the module B2, and the power supply direct current buses 1-are continuously compensated;
Step5, when one group of the direct current breakers 1ZK 1-1 ZK3 and 2ZK 1-2 ZK3 is completely disconnected, and the bus transfer switch 1ZK4 is in a disconnected state, the bidirectional DC-DC compensator DC1 is immediately started, when the direct current breakers 1ZK 1-1 ZK3 are disconnected, the modules B2 and B3 are started, power is supplied to the power supply direct current buses KM2+, KM 2-by the power supply direct current buses KM1+, KM1-, and the voltage ratio between the input end of the module B3 and the output end of the module B2 is adjusted to be 1:1;
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 KM2-by 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 be 1:1.
Claims (5)
1. Self-healing direct current system with intelligent busbar decompression compensation function, including two sets of interconnect's direct current system 1# and 2#, its characterized in that:
A power supply direct current busbar KM1+ and KM 1-are arranged in the 1# direct current system;
The charger 1AD of the No. 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 a 1# direct current system through a direct current breaker 1ZK 2;
the No. 1 storage battery module is connected with power supply DC buses KM1+, KM1-through a DC breaker 1ZK3,
A power supply direct current busbar KM2+ and KM 2-are arranged in the 2# direct current system;
The charger 2AD of the No. 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 No. 2 storage battery module is connected with a charger 2AD of a No. 2 direct current system through a direct current breaker 2ZK 2;
the No. 2 storage battery module is connected with the power supply DC buses KM2+, KM2-through a DC breaker 2ZK3,
The power supply direct current buses KM1+, KM1-and KM2-are connected through a bus transfer switch 1ZK4, a bidirectional DC-DC compensator DC1 is arranged between the power supply direct current buses KM1+, KM1-and the direct current buses KM2+, 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 the controller U1;
Voltage detection devices 1DV3 and 2DV3 are respectively arranged on the power supply direct current buses KM1+, KM1-and the power supply direct current buses KM2+, KM2-;
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-tie transfer switch 1ZK4 are electrically connected with the input end of the controller U1;
The bidirectional DC-DC compensator DC1 is composed of 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 electrodes 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 KM2-.
2. The self-healing direct current system with the intelligent bus voltage loss compensation function according to claim 1, wherein the H bridge in the module B3 consists of MOSFET tubes Q9-Q12, two ends of the MOSFET tubes Q9 and Q10 are electrically connected with positive and negative poles of the H bridge of the module B1 and the H bridge connecting end of the module B2, capacitors C6 and C7 connected in series are connected with two ends of the MOSFET tubes Q9 and Q10 in parallel, one end of a primary coil of the isolation transformer T1 is connected with the middle point of the MOSFET tubes Q9 and Q10, and the other end of the primary coil of the isolation transformer T1 is connected with the middle point 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 an H bridge in series, the other ends of the MOSFET tubes Q11 and Q12 are connected in parallel and then are 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 KM2-.
3. The self-healing direct current system with intelligent bus voltage loss compensation function according to claim 2, wherein the primary coil of the isolation transformer T1 is connected with the capacitor C8 in series, and two ends of the primary coil connected with the capacitor C8 in series are respectively and electrically connected with the middle points of the MOSFET tubes Q9 and Q10 and the middle points of the capacitors C6 and C7.
4. The self-healing direct current system with intelligent bus voltage loss compensation function according to claim 3, wherein a capacitor C9 is arranged at the connecting end of the module B3 and the power supply direct current buses KM2+, KM2-, and a capacitor C5 is arranged at the connecting end of the module B3 and the module B1/B2.
5. The self-healing direct current system with the intelligent bus voltage loss compensation function according to claim 4, wherein the 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 the middle points of the two series branches, and two ends of the MOSFET tubes Q3 and Q4 are electrically connected with the module B2;
The H bridge in the module B2 consists of MOSFET (metal-oxide-semiconductor field effect transistor) transistors Q5-Q8, the MOSFET transistors Q5 and Q6 are connected in series, the MOSFET transistors 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 transistors Q7 and Q8 are electrically connected with the module B1;
The gates S1-S12 of the MOSFET transistors Q1-Q12 are electrically connected with the output end of the controller U1.
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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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