Multifunctional replacement device for failure battery of direct-current storage battery pack of transformer substation

Abstract

The invention relates to a multifunctional replacement device for a failure battery of a direct-current storage battery pack of a transformer substation, which comprises a multifunctional storage battery junction box, a controller U1 is arranged in the multifunctional storage battery junction box, and the input end of the controller U1 is connected with a reference voltage unit for providing reference voltage for the controller U1 and a measuring unit for measuring the voltage of a storage battery. The input end of the measuring unit is connected with a battery short circuit unit; the output end of the controller U1 is connected with an optical coupling isolation drive circuit, and the output end of the optical coupling isolation drive circuit is connected with the input end of the battery short circuit unit. The device has the advantages that the structure is reasonable, online replacement can be achieved without power failure, polarity reverse connection misoperation is prevented, and the replacement speed is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of substation direct current systems, and in particular relates to a multifunctional replacement device for failed batteries of a direct current storage battery group in a substation. Background Art

[0002] At present, the secondary DC system of the power control system is mainly powered by batteries. Due to the failure of the battery power supply, power facilities are damaged, DC system fails, accidents expand to grid failures, and even cause personal injury and death. Therefore, it is very necessary to study the battery maintenance technology in the secondary DC system; the battery is known as the "blood" of the DC power supply system and is the best line of defense to ensure the normal operation of the equipment, especially in ultra-high voltage substations. Once a DC battery group fails, it will cause immeasurable consequences; the current domestic method for replacing a single unqualified battery is generally to disconnect the battery group from the DC bus and the floating charger, remove the unqualified battery, and perform three charge and discharge tests separately. If it is still unqualified, replace it with a new single qualified battery, and then add the DC bus and floating charger to the connection after the wiring is correct; this method of replacing unqualified batteries not only greatly reduces the replacement speed, but also has the following disadvantages: 1) When removing and replacing the unqualified battery pool, the group needs to be shut down 1) When a single battery group is operated for a long time, if the operating battery charger fails to output a fault, the DC bus will be completely stopped, affecting the reliability of the DC system and easily causing other safety accidents; 2) When replacing the battery, there is a need to rewire the connection, and there is a risk of reverse polarity. If the polarity is reversed, there is a risk of battery explosion, causing harm to personnel and equipment; 3) During the battery replacement process, the current and voltage of the battery group will change, and the change cannot be grasped in time. If the change exceeds the limit and the operator is unaware of it, it will also affect the reliability of the DC system and easily cause other safety accidents; 4) After removing the unqualified battery, it is necessary to continue to carry out verification charging and discharging experiments to check whether the capacity of other batteries is qualified. The wiring also needs to be rewired and the polarity needs to be checked. If the polarity is reversed, it will cause dangers such as battery explosion; therefore, it is very necessary to provide a multifunctional replacement device for failed batteries of DC battery groups in substations that has a reasonable structure, can be replaced online without power outage, prevents reverse polarity connection and misoperation, and increases the replacement speed. Summary of the invention

[0003] 1. Technical issues

[0004] In view of the above-mentioned existing technical status, this application mainly addresses the following technical problems:

[0005] 1. When removing and replacing unqualified battery cells, the battery group needs to be shut down, which will cause the DC bus to stop completely, affecting the reliability of the DC system and easily causing other safety accidents;

[0006] 2. When replacing the battery, there is a risk of rewiring the battery, which may cause the battery to explode, causing damage to personnel and equipment.

[0007] 3. During the battery replacement process, the battery pack current and voltage will change, which will affect the reliability of the DC system and easily cause other safety accidents;

[0008] 4. After removing the unqualified battery, it is necessary to continue to carry out the verification charge and discharge test to check whether the capacity of other batteries is qualified. It is also necessary to change the wiring and check the polarity. If the polarity is connected in reverse, it may cause danger such as battery explosion.

[0009] (II) Technical solution

[0010] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a multifunctional replacement device for failed batteries of a DC battery pack in a substation which has a reasonable structure, is easy to operate and use, and reduces the pain.

[0011] The objective of the present invention is achieved as follows: a multifunctional replacement device for failed batteries of a DC battery pack in a substation, comprising a multifunctional battery junction box, wherein a controller U1 is provided in the multifunctional battery junction box, wherein the input end of the controller U1 is connected to a reference voltage unit for providing a reference voltage to the controller U1 and a measuring unit for measuring the battery voltage, wherein a battery short-circuiting unit is connected to the input end of the measuring unit; an output end of the controller U1 is connected to an optocoupler isolation drive circuit, wherein the output end of the optocoupler isolation drive circuit is connected to the input end of the battery short-circuiting unit.

[0012] Furthermore, the reference voltage unit includes a resistor R1, a resistor R3 connected in series with the resistor R1, and a capacitor C4 connected in parallel with the resistor R1; one end of the resistor R1 is grounded, and the other end is connected to the input end of the controller U1 and connected to a high level through the resistor R3.

[0013] Furthermore, the measuring unit includes resistors R7, R8 and a diode VD1; one end of the resistor R7 is connected to the input end of the controller U1, the other end is grounded via the diode VD1, and connected to the anode of the thyristor VS via the resistor R8.

[0014] Furthermore, the battery multifunctional junction box also includes an alarm unit, which includes indicator lights H1, H2, and H3; the positive pole of the indicator light H1 is connected to a high level, the negative pole is connected to the controller U1 via a resistor R4, and is connected to the cathode of the thyristor VS via a resistor R4; the alarm form of the alarm unit is to prompt through the indicator light.

[0015] Furthermore, the multifunctional battery junction box also includes an anti-error unit, which includes diodes VD2, VD3 and an optocoupler isolation module U2; the VCC terminal of the optocoupler isolation module U2 is connected to the power supply terminal Vcc (+5V), the GND terminal is grounded, the A terminal is connected to the power supply terminal Vcc (+5V) via a resistor R2, the K terminal is connected to the P1.5 terminal of the controller U1, and the VO terminal is connected to the control electrode (G) of the thyristor VS via a resistor R9.

[0016] Furthermore, the cathode of the diode VD2 is connected to the control electrode (G) of the thyristor VS, and the anode is connected to the anode of the diode VD3.

[0017] Furthermore, the cathode of the diode VD3 is connected to the cathode (K) of the thyristor VS, and the cathode is grounded; the cathode (K) of the thyristor VS is connected to the negative electrode of the battery, and the anode (A) is connected to the positive electrode of the battery.

[0018] Furthermore, the battery multifunctional junction box also includes a power supply unit, which includes a DC-DC power converter U3; the Vin- terminal of the DC-DC power converter U3 is connected to the negative electrode of the 12V high-performance lithium battery, and the Vin+ terminal is connected to the positive electrode of the 12V high-performance lithium battery via a fuse F1.

[0019] Furthermore, a polarity capacitor C1 and a capacitor C2 are provided between the Vin- terminal and the Vin+ terminal of the DC-DC power converter U3; a polarity capacitor C3 and a capacitor C5 are provided between the COM terminal and the Vo+ terminal of the DC-DC power converter U3; the positive electrode of the polarity capacitor C3 is connected to the power supply terminal Vcc (+5V), and the negative electrode is grounded.

[0020] Furthermore, the multifunctional battery junction box also includes a status display unit, which is composed of a detection circuit, a 16-bit A / D conversion module, a built-in 5PPM voltage reference source and an integrated board.

[0021] (III) Beneficial effects

[0022] 1. The multifunctional replacement device for outdated batteries proposed in the present invention can replace outdated batteries in floating charge state without exiting charging and releasing dual standby, and can monitor the changes of battery current and voltage in real time to prevent the occurrence of erroneous operations such as reverse polarity connection, thus fully ensuring the safe and reliable operation of the DC system of the substation;

[0023] 2. The device of the present invention realizes efficient work load reduction through real-time display of current, improves work efficiency, reduces the operating risks of substation automation and protection equipment during the DC system battery maintenance process, ensures the safe and stable operation of the power grid, and has promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the multifunctional battery wiring device of the present invention.

[0025] Figure 2 It is a circuit diagram of each part of the power supply of the present invention.

[0026] Figure 3 It is the electrical principle wiring diagram of the present invention.

[0027] Figure 4 This is a composition diagram of the substation DC system of the present invention.

[0028] Figure 5 This is a schematic diagram of the battery pack of the present invention supplying power to the outside.

[0029] Figure 6 It is a structural diagram of a battery of the present invention.

[0030] Figure 7 It is a structural diagram of a lead-acid battery of the present invention.

[0031] Figure 8 This is a circuit diagram of the battery polarity automatic judgment function of the present invention.

[0032] Fig. 9 This is a voltage digital-to-analog conversion principle diagram of the present invention.

[0033] Fig.10 It is the voltage acquisition circuit diagram of the present invention.

[0034] Fig.11 It is a schematic diagram of the operation of the battery pack of the present invention.

[0035] Fig.12 It is a schematic diagram of battery jumper of the present invention. DETAILED DESCRIPTION

[0036] The key point to ensure the normal operation of the secondary DC system is to maintain the power supply of the battery pack. In the substation, as the last line of defense for the entire DC power supply system to provide power supply guarantee for the equipment network, the importance of the battery pack in the substation DC system is self-evident. Once the battery is not properly maintained, it will bring potential risks to the safe and stable operation of the power grid; because when the substation occupies the power supply and causes a power outage, it is very easy to cause a power grid accident; to ensure the safe and stable operation of the power grid, it is necessary to replace a single, multiple faulty batteries or the entire battery pack in the operating battery pack; after the application of the new multifunctional battery wiring device, the battery explosion caused by wrong wiring is avoided, the personal injury and equipment risk are minimized, and the influence of grounding on secondary equipment is avoided, ensuring the reliability of the power grid.

[0037] Domestic and foreign power companies and power industry enterprises have been exploring and researching battery maintenance for quite a long time. The main research direction is to strengthen online monitoring and intelligent analysis of batteries. When problems are found in batteries, they need to be replaced quickly, but there is no good solution. At present, domestic replacement of failed batteries generally involves disconnecting the DC power supply, connecting the spare battery to the charger, and then withdrawing the battery to be replaced, which greatly reduces the replacement speed and affects the safety of DC system operation. In view of this, the present invention provides an online battery replacement device that does not require power outages and can directly replace batteries, thereby increasing the replacement speed while ensuring safety. The purpose of the present invention is to solve the current problem that batteries cannot be replaced without power outages, so as to improve labor productivity, improve enterprise economic benefits and quality service levels.

[0038] The present invention is further described below in conjunction with embodiments and / or drawings.

[0039] Example 1

[0040] like Figure 1-12 As shown, a multifunctional replacement device for failed batteries of a DC battery pack in a substation includes a multifunctional battery junction box, in which a controller U1 is provided, an input end of the controller U1 is connected to a reference voltage unit for providing a reference voltage to the controller U1 and a measuring unit for measuring the battery voltage, and a battery short-circuiting unit is connected to the input end of the measuring unit; an output end of the controller U1 is connected to an optocoupler isolation drive circuit, and the output end of the optocoupler isolation drive circuit is connected to the input end of the battery short-circuiting unit.

[0041] The reference voltage unit includes a resistor R1, a resistor R3 connected in series with the resistor R1, and a capacitor C4 connected in parallel with the resistor R1; one end of the resistor R1 is grounded, and the other end is connected to the input end of the controller U1 and connected to a high level through the resistor R3.

[0042] The measuring unit includes resistors R7, R8 and a diode VD1; one end of the resistor R7 is connected to the input end of the controller U1, and the other end is grounded via the diode VD1 and connected to the anode of the thyristor VS via the resistor R8.

[0043] The multifunctional battery junction box also includes an alarm unit, which includes indicator lights H1, H2, and H3; the positive pole of the indicator light H1 is connected to a high level, and the negative pole is connected to the controller U1 via a resistor R4, and is connected to the cathode of the thyristor VS via the resistor R4; the alarm unit uses an indicator light to prompt the alarm.

[0044] The multifunctional battery junction box also includes an anti-error unit, which includes diodes VD2, VD3 and an optocoupler isolation module U2; the VCC terminal of the optocoupler isolation module U2 is connected to the power supply terminal Vcc (+5V), the GND terminal is grounded, the A terminal is connected to the power supply terminal Vcc (+5V) via a resistor R2, the K terminal is connected to the P1.5 terminal of the controller U1, and the VO terminal is connected to the control electrode (G) of the thyristor VS via a resistor R9.

[0045] The cathode of the diode VD2 is connected to the control electrode (G) of the thyristor VS, and the anode is connected to the anode of the diode VD3.

[0046] The cathode of the diode VD3 is connected to the cathode (K) of the thyristor VS, and the cathode is grounded; the cathode (K) of the thyristor VS is connected to the negative electrode of the battery, and the anode (A) is connected to the positive electrode of the battery.

[0047] In the present invention, the error prevention unit mainly plays the role of positive and negative phase voltage stabilization clamping.

[0048] The battery multifunctional junction box also includes a power supply unit, which includes a DC-DC power converter U3. Figure 2 As shown; the Vin- terminal of the DC-DC power converter U3 is connected to the negative electrode of the 12V high-performance lithium battery, and the Vin+ terminal is connected to the positive electrode of the 12V high-performance lithium battery via the fuse F1.

[0049] A polarity capacitor C1 and a capacitor C2 are provided between the Vin- terminal and the Vin+ terminal of the DC-DC power converter U3; a polarity capacitor C3 and a capacitor C5 are provided between the COM terminal and the Vo+ terminal of the DC-DC power converter U3; the positive electrode of the polarity capacitor C3 is connected to the power supply terminal Vcc (+5V), and the negative electrode is grounded.

[0050] In the present invention, the 12V voltage of the 12V high-performance lithium battery is stepped down to 5V by the DC-DC power converter U3, and the stepped-down 5V voltage is supplied to the jumper device; thus, the goal of safely removing or replacing the tested battery and then putting it into operation is achieved without affecting the continuous power supply of the DC system.

[0051] The present invention is a multifunctional replacement device for failed batteries of a DC battery pack in a substation. During use, the device of the present invention can determine the wiring polarity, has an audible and visual alarm, and also has current and voltage display. The junction box equipped with multiple quick wiring posts is convenient for on-site testing and improves on-site work efficiency. The present invention effectively solves the problem that the positive and negative poles need to be distinguished before connecting the battery, and the polarity of the battery to be replaced needs to be manually determined. The present invention can realize online operation, and the lagging battery can be replaced in a floating charge state without exiting charging to release the double standby, and can monitor the battery current and voltage changes in real time to prevent the occurrence of erroneous operations such as reverse polarity connection, and fully ensure the safe and reliable operation of the DC system of the substation. The present invention solves the problem that the battery cannot be replaced online, avoids the battery explosion caused by wrong wiring, minimizes personal injury and equipment risks, and avoids the influence of grounding on secondary equipment, ensures the reliability of the power grid, and is of great significance for the maintenance of the DC system of the substation. The present invention has the advantages of reasonable structure, online replacement without power outage, prevention of erroneous operation due to reverse polarity connection, and increased replacement speed.

[0052] Example 2

[0053] like Figure 1-12 As shown, a multifunctional replacement device for failed batteries of a DC battery pack in a substation includes a multifunctional battery junction box, in which a controller U1 is provided, an input end of the controller U1 is connected to a reference voltage unit for providing a reference voltage to the controller U1 and a measuring unit for measuring the battery voltage, and a battery short-circuiting unit is connected to the input end of the measuring unit; an output end of the controller U1 is connected to an optocoupler isolation drive circuit, and the output end of the optocoupler isolation drive circuit is connected to the input end of the battery short-circuiting unit.

[0054] The multifunctional battery junction box also includes a status display unit, which is composed of a detection circuit, a 16-bit A / D conversion module, a built-in 5PPM voltage reference source and an integrated board.

[0055] In the present invention, the status display unit can display the working status of the replacement jumper working battery pack, including parameter information such as voltage and current.

[0056] The function of the battery voltage test is mainly to detect the voltage of the batteries in the entire battery pack. The detection system is mainly composed of a detection circuit, a 16-bit A / D conversion module and an integrated board. First, the collected battery voltage is amplified and filtered, and then input into the integrated board after A / D conversion. The integrated board encodes the data and realizes data transmission through communication with the main circuit of the device, and finally displays the data on the screen.

[0057] At the same time, in order to ensure the integrity and stability of the voltage measurement value, the module has a built-in 5PPM voltage reference source and a 16-bit high-speed A / D conversion chip, which is used to ensure that the voltage measurement error is less than 0.1 and solve the problem of temperature drift. Its working principle is as follows Fig. 9 shown.

[0058] In order to ensure that the system can work normally and orderly and to ensure the accuracy and integrity of voltage detection, the voltage sampling circuit uses a linear optocoupler isolation chip HCNR201, which consists of an AIGASLED and two photosensitive diodes PD1 and PD2; among them, the main function of PD1 is to suppress the drift of the light emitted by the LED, improve the linearity of the LED light, and monitor the intensity of the light emitted by the LED; and the PD2 photosensitive diode is used to emit a set of photocurrents proportional to the intensity of the LED light; because PD1 and PD2 are in the same chip, their characteristics are almost the same, so when the LED emits light, the photosensitive diodes PD1 and PD2 can both receive the light of the LED at the same time, and the amount received is also proportional, which can effectively avoid unnecessary external influences and make it have good and stable linearity. The voltage detection circuit diagram is as follows Fig.10 shown.

[0059] The method of monitoring the battery current is relatively simple, mainly by embedding an integrated current transformer to complete the current collection; specifically, a current transformer of appropriate capacity is installed on the positive and negative buses of the device test circuit, and then the detected current value is converted through an A / D conversion chip, and finally the obtained data is displayed on the monitoring system.

[0060] The multifunctional battery junction box also includes a jumper unit.

[0061] In the present invention, although it is possible to detect the battery internal resistance in time to find the battery that is about to fail, this method cannot be guaranteed to be absolutely reliable. Some batteries appear normal during detection, but the internal structure is close to the end. Once the AC power supply is lost at this time, the high-intensity power supply current of the system under the DC power supply state will cause the defective battery to collapse quickly, and the entire system will lose power in an instant, which will cause irreparable huge losses.

[0062] from Fig.11From the working diagram of the battery pack, it can be seen that at this time, the entire battery pack will provide a working current Ia and generate a voltage drop VRb on each internal resistance Rb. If battery E2 fails, Rbz increases, and VRb: increases accordingly. The terminal voltage of this battery Vb2=EYVRb2. If IA=20A, when the internal resistance Rb increases to 200mΩ, VRb will reach 4V. When the internal resistance of the battery continues to increase, the reverse voltage generated at both ends of the battery will increase sharply, causing the power supply circuit to collapse or even the failed battery to explode.

[0063] The decoupling of the power supply system will cause a large-scale system collapse, the economic losses will be extremely huge, and the social impact will be immeasurable. The triggering point is that there is a very serious safety hazard in the use of the battery pack. In order to ensure the safety and stability of the system, operation and maintenance personnel often need to replace all batteries in advance according to the working life of the batteries. Through a lot of data analysis and research, it is found that the actual service life of the battery is often only 55% of the design life cycle.

[0064] In the present invention, in the design of the multifunctional battery connection device of the substation, a gapless bridging method of the failed battery is adopted to provide an additional current path I for the faulty battery (E2) circuit. B (like Fig.12 When the battery pack is running, the total current of the whole battery pack is I A If one of the batteries fails (assuming it is E2), the current I through the failed battery E2 is E It will become smaller due to the increase of its internal resistance Rb2. At this time, another current path I is provided. B For current I A Perform controllable diversion and obtain the following expression I A =I B +I E , thus completing the seamless automatic cross-connection of the faulty battery, fundamentally eliminating the adverse impact on the entire power grid caused by the sudden failure of a certain battery, and ensuring the reliability and safety of the power grid to the greatest extent.

[0065] In the present invention, the device of the present invention can be operated in the following three states: 1. The battery pack is not disconnected from the charger, and the battery pack is in a floating charge state, and the faulty battery can be directly replaced; 2. During the replacement process, if the charger input end is powered off or the charger fails, the faulty battery can be directly replaced; 3. During the replacement process, if a high-power reclosing device is activated, the faulty battery can be directly replaced.

[0066] The present invention is a multifunctional replacement device for failed batteries of a DC battery pack in a substation. During use, the device of the present invention can determine the wiring polarity, has an audible and visual alarm, and also has current and voltage display. The junction box equipped with multiple quick wiring posts is convenient for on-site testing and improves on-site work efficiency. The present invention effectively solves the problem that the positive and negative poles need to be distinguished before connecting the battery, and the polarity of the battery to be replaced needs to be manually determined. The present invention can realize online operation, and the lagging battery can be replaced in a floating charge state without exiting charging to release the double standby, and can monitor the battery current and voltage changes in real time to prevent the occurrence of erroneous operations such as reverse polarity connection, and fully ensure the safe and reliable operation of the DC system of the substation. The present invention solves the problem that the battery cannot be replaced online, avoids the battery explosion caused by wrong wiring, minimizes personal injury and equipment risks, and avoids the influence of grounding on secondary equipment, ensures the reliability of the power grid, and is of great significance for the maintenance of the DC system of the substation. The present invention has the advantages of reasonable structure, online replacement without power outage, prevention of erroneous operation due to reverse polarity connection, and increased replacement speed.

[0067] The present invention further describes the solution of the present invention to facilitate understanding of the technical solution of the present invention, and the specific contents are as follows:

[0068] ① Composition and characteristics of substation DC system

[0069] The DC system is a very important component of the substation. Its main task is to provide power to relay protection devices, circuit breaker operations, and various signal circuits. The normal operation of the DC system will directly affect whether the relay protection circuit and circuit breaker can work properly, which will in turn affect the reliable operation of the entire substation and even the entire regional power grid. When the substation is working normally, it provides the energy required for closing the circuit breaker in the substation. When a substation fails, it provides the required power to relay protection, automatic devices, circuit breaker tripping and closing, communications, substation machinery and other equipment. Therefore, the reliable operation of the DC system directly determines the safety of the power system. The composition of the DC system is as follows: Figure 4 .

[0070] DC charging devices are easily affected by the outside world. Loss of AC voltage will affect the output. Aging and damage of electronic equipment and components will cause device failure or instability. DC loads cannot be powered off and require a stable and reliable power supply. Storage battery packs are independent of other power sources and are not affected by the outside world. They have the characteristics of stable output, good voltage quality, and are limited by capacity.

[0071] The DC system of a substation is the heart of the substation, and the most important part of the DC system is the battery pack. The battery pack is the most important link in the entire DC system and is also the most arduous link in maintenance work. Only by maintaining the battery pack well can the safe and reliable operation of the DC system be ensured. At present, most substations are equipped with valve-regulated lead-acid batteries. This type of lead-acid battery will sulfide in harsh working environments or if it is not properly maintained, which directly affects the charge and discharge performance of the battery pack. The "Technical Regulations for Operation and Maintenance of Battery DC Power Supply Devices for Power Systems" stipulates that the DC power supply system of a substation must be inspected and maintained once a year. During maintenance, the battery needs to be subjected to a verification charge and discharge test to eliminate sulfide, extend the battery life, and improve the charge and discharge performance.

[0072] During the discharge and routine maintenance process, if the lagging battery has low voltage at the beginning of discharge, or even open circuit, heat and other emergency conditions, and the battery pack cannot continue to perform discharge detection, the current on-site method is to disassemble the lagging battery and then connect the circuit to continue discharging. The disassembly process is complicated and there is a great safety risk. There is no safe and effective protection method. Another solution is to use a simple jumper device (such as a jumper). Although it avoids battery disassembly, its fixed embedding effect can easily cause irreversible damage to the lagging battery and misjudge the capacity of the entire battery group. In daily maintenance work, a device is also needed to detect lagging single batteries that are inconvenient to disassemble but need to be operated online for a long time.

[0073] ②The influence of battery internal resistance on discharge capacity

[0074] When the AC power fails and the rectifier module loses its ability to supply power to the DC system, the battery pack starts to supply power to the DC system. Figure 5 As shown, because each battery has internal resistance, a voltage opposite to the battery voltage will be generated at both ends of the battery. The voltage is: I 放 *R 内阻 (The product of discharge current and internal resistance); Under normal circumstances, the internal resistance of the battery is extremely small, generally in the milliohm level, so the voltage drop is also extremely small, and the voltage drop across the battery is limited.

[0075] When the internal resistance of a battery suddenly increases, the voltage drop will increase sharply, and the voltage across the battery will quickly drop below the discharge voltage. At this time, the excessive voltage drop will also aggravate the deterioration of the battery, entering a vicious circle, and ultimately causing insufficient group pressure or directly causing the battery to be damaged and open-circuited due to the excessive voltage drop, completely losing the ability to supply power to the outside.

[0076] ③Battery open circuit reason

[0077] Since the battery pack is composed of single batteries connected in series by connecting strips and then connected to the busbar, there are relatively many connecting wires in each normally operating battery pack. Therefore, damage to the connecting wires and loose fixation are also reasons for the open circuit of the battery pack. Generally, staff will regularly perform visual inspections and sanitation cleaning on the battery pack. After the connecting wires are disconnected, the sorting module will no longer charge the battery pack because there is no complete charging circuit. The battery will generate an alarm due to the loss of its own capacity, resulting in a drop in voltage. Therefore, the battery open circuit caused by the connecting lines will be detected by the staff in a timely manner.

[0078] ④ Principle of online bypass of lagging battery

[0079] The battery pack is an independent and stable power source, not restricted by the AC power supply. When any emergency occurs in the power plant or substation, even if all the AC power supplies have problems, the DC system can still supply power normally, and the electrical equipment works reliably and continuously with stable voltage. At the same time, it can also be used as the emergency lighting power supply for the entire plant and the entire station. This is the last barrier to ensure that the power supply is not interrupted. The battery pack is composed of multiple battery packs connected in series and in parallel. During the long-term working process, the battery pack will gradually fail due to various physical and chemical reaction factors. This failure process is usually caused by a single or partial singularity that causes the entire battery to fail. The battery pack is composed of multiple battery packs connected in series. In the series circuit, if any battery unit fails, this will cause the charge and discharge capacity of the entire battery to be reduced or lost. In the battery's In the early stages, undervoltage conditions such as low voltage or high temperature may occur, causing the battery pack to be unable to detect discharge; currently, when there is a lagging battery pack, almost all battery packs are replaced. Replacing the battery pack means a very expensive price, which includes the purchase, disassembly, installation and transportation costs of the battery pack. The biggest cost is also the environmental pollution caused by battery waste. When the battery pack is connected to the load, the voltage of each single battery is measured, and the voltage is lower than that of the reverse battery. Principle: The reverse battery refers to a battery with a large internal resistance. When the internal resistance becomes larger, the internal resistance of the battery actually becomes part of the load, and a voltage drop occurs. Therefore, the normal battery voltage is basically the same, and the battery end lags behind. The voltage drop caused by the internal resistance is opposite to the polarity of the battery and is offset by a part, so the terminal voltage is lower.

[0080] For the current DC system battery pack capacity detection discharge and routine maintenance process, the battery pack has low voltage, even open circuit, heat and other emergency situations in the early stage of discharge, and the discharge detection problem cannot be continued. The battery at the rear is partially disassembled, and then the discharge connection ring is continued. The disassembly process is complicated and there are great safety hazards. There is no safe and effective protection method. Another solution is to use a simple bridging device. Although it avoids the disassembly of the battery, its fixed embedding effect may cause irreversible damage to the rear battery and misjudge the entire battery capacity result. In daily maintenance work, a device is also needed. The device finds that the disassembly of the rear battery pack is inconvenient, but requires long-term online operation.

[0081] ⑤Technical solution of the present invention

[0082] The purpose of the present invention is to solve the problem that it is currently impossible to better use batteries without power failure, so as to improve labor productivity, improve enterprise economic benefits and quality service levels; the functions of the device proposed by the present invention include: (1) automatic judgment of battery memory: before connecting the battery, the device needs to distinguish the positive and negative poles, and manually judge the polarity of the battery to be replaced, and then connect it; (2) simple battery wiring function: a multifunctional DC battery junction box, including a junction box, which is provided with a group of test circuits, a main circuit, two parallel multi-head quick wiring posts and a display circuit; (3) battery working status monitoring function: a multifunctional DC battery junction box, which is provided with a group of display circuits, which are connected to a display screen, and the display screen displays the current parameters passing through the main circuit, and monitors in real time whether the online battery group is interrupted; its structural schematic diagram is shown as follows Figure 3 shown.

[0083] ⑥ Study the problems existing in the operation of existing battery replacement methods and analyze the conditions required for online replacement of backward batteries

[0084] Before connecting the battery, the junction box (with a diode inside) must distinguish the positive and negative poles, and manually judge the polarity of the battery to be replaced before connecting it. If it is connected incorrectly, it will cause a battery short circuit (short-circuit DC current is 200-400A, and the AC current of a general welding machine is around 120-200A). In addition, the space between battery layers is very low, which can easily cause the DC system to be grounded, which may cause drastic fluctuations in the DC system voltage, resulting in burning of substation equipment or tripping of protection action.

[0085] After connection, the connection status cannot be reflected in real time. One person needs to clamp the circuit with a DC clamp to monitor the power supply of the circuit. When replacing the entire battery group and incorporating the temporary battery group, the battery fuse is under the cabinet and very close to the cabinet body, and the fuse terminal is wide. The temporary battery terminal clamp cannot be clamped and connected at one time when connected. It is necessary to repeatedly change the direction of the clamp to find the most stable position. The two groups of batteries will repeatedly contact due to the voltage difference, which will cause sparks and DC system voltage fluctuations, which will affect and damage the DC system control unit and measurement and control components; the battery structure is as follows: Figure 6-7 shown.

[0086] Since the wiring of the capacity meter is divided into current and voltage wiring clamps, a total of 4 clamps, during capacity testing, there is often not enough space under the fuse to clamp all 4 clamps at the same time, which affects the disconnection of the battery pack.

[0087] The positive and negative wires of the junction box cannot be removed when not in use, which is inconvenient to carry and store. The wires are exposed and can easily be crushed and scattered during transportation, causing electric shock and equipment risks.

[0088] ⑦ Research on automatic battery polarity determination technology and multiple detection and protection technology during online replacement

[0089] Before connecting the battery, the junction box (with a diode inside) must distinguish the positive and negative poles, and manually judge the polarity of the battery to be replaced before connecting it. If it is connected incorrectly, it will cause a short circuit in the battery. The space between the battery layers is very low, which may easily cause the DC system to be grounded, which may cause a sharp fluctuation in the DC system voltage, resulting in the burning of the substation equipment or the tripping of the protection action. Therefore, the equipment should have a current direction indication function and an automatic reminder function; its functional circuit is as follows: Figure 8 shown.

[0090] ⑧ Research and develop simple wiring mode for battery replacement and overall design of the device

[0091] The research and design of a jumper device can directly replace the battery without causing power outages in the substation. The technical path of this design is a jumper device behind the battery, which is connected by a wire, a central control unit, and a battery pole clamping device at both ends of the wire. The device is designed to be easy to operate, capable of trouble-free replacement of batteries in the substation, and capable of directly replacing the battery online.

[0092] When replacing a whole set of batteries and incorporating a temporary battery pack, the battery fuse is located under the cabinet, very close to the cabinet body, and the fuse terminal is wide. The temporary battery terminal clamp cannot be clamped and connected at once during connection. It is necessary to repeatedly change the direction of the clamp to find the most stable position. Repeated contact between the two battery groups due to the voltage difference may cause sparks and DC system voltage fluctuations, which will affect and damage the DC system control unit and measurement and control components.

[0093] The multifunctional DC battery junction box comprises a junction box, inside which a group of test circuits, a main pass circuit, two parallel multi-head quick terminal posts and a display circuit are arranged.

[0094] The positive and negative output lines of the test circuit are parallel to the positive and negative output lines of the junction box; an audible and visual alarm is also provided in series with the test circuit.

[0095] The positive and negative outgoing wires of the test circuit are parallel to the positive and negative outgoing wires of the main circuit and are electrically independent.

[0096] The positive and negative poles of the main circuit are each provided with two DC fast terminals, and a current shunt is connected in series in the circuit, and a display circuit is added in parallel with the shunt.

[0097] The display circuit is connected to the display screen, which displays the current parameters passing through the main circuit and monitors in real time whether the online battery pack is interrupted. The overall circuit design is as follows: Figure 3 shown.

[0098] The two parallel multi-head quick-connect terminals have the following functions:

[0099] (1) Lead the power supply from the upper end of the main fuse at the bottom of the panel cabinet to the junction box. Since the junction box quick connector is not integrated with the temporary battery at this time, sparking and voltage instability are avoided during operation;

[0100] (2) When checking the battery capacity, provide multiple terminals to the capacity checker to meet the test clip sampling requirements;

[0101] (3) The wiring of the junction box can be easily removed and the line can be put back into the device to protect the wiring of the junction box and facilitate transportation.

[0102] The function of the test circuit is to test connect the two poles of the faulty battery with the same polarity of the test circuit before using the main circuit to jumper the damaged faulty battery. When the polarity is reversed, there will be an audible and visual alarm to remind the staff of the wrong position.

[0103] The multifunctional battery wiring device for a substation of the present invention is equivalent to a unidirectionally conducting diode, which can withstand reverse voltage and ensure that the replaced battery is bypassed; when a battery failure occurs in a battery pack in the substation, the multifunctional battery wiring device is directly connected to bypass the faulty battery, which will not cause an internal short circuit in the battery and power failure of the battery pack; when a battery failure occurs in the battery pack and the battery pack power supply cannot be withdrawn, the method for handling the battery failure is: directly use a battery in series with the multifunctional battery wiring device, and connect the two ends of the faulty battery in parallel, so as to replace the faulty battery; the total voltage of the battery pack remains unchanged, and the battery pack can operate normally after the failure is resolved.

[0104] 1. The device of the present invention replaces a faulty battery. After testing, the faulty battery is determined to be a defective battery. In order to replace the battery in operation without powering off, the faulty battery needs to be bridged and the main circuit passage is maintained.

[0105] The operation process is as follows:

[0106] Step 1: Determine the battery position before and after the faulty battery;

[0107] Step 2: To ensure that the batteries before and after the jumper barrier battery do not short-circuit, the positive pole of the battery in front of the barrier battery must be connected to the negative pole of the main circuit of the junction box, and the negative pole of the battery behind the barrier battery must be connected to the positive pole of the main circuit of the junction box;

[0108] Step 3: To prevent wrong connection during jumper connection, use a test circuit to test the poles of the batteries to be connected before connecting.

[0109] Step 4: Isolate the faulty battery through jumper connection and remove it. During the operation, the current flowing through the battery pack is displayed in real time to understand whether the jumper circuit is working properly.

[0110] 2. The present invention performs capacity test wiring on the entire group of batteries to be tested for capacity.

[0111] For example, before conducting capacity verification on a 110kV substation, it is necessary to connect a temporary battery group with the same pole in parallel on the load side of the lower part of the battery group to be verified, and then pull out the fuse to isolate the battery group to be verified. Since the fuse is in a narrow position and is close to the panel cabinet, the fuses are of different sizes, resulting in a small contact area at the bottom, and the surrounding space is narrow. There are many wiring clamps on the battery verification instrument, making wiring difficult. Repeated wiring is prone to sparks, and the possibility of loosening and touching the panel cabinet grounding may occur during the wiring process.

[0112] 3. Innovations of the present invention:

[0113] (1) Propose a test circuit function module to test and confirm polarity before replacement to avoid misjudgment and improve safety;

[0114] (2) Propose multiple monitoring and protection functions, design monitoring and display function modules, perform real-time sampling of voltage and current, and confirm that the wiring is reliable;

[0115] (3) Design bypass and protection modules to achieve the goal of replacing a single battery without shutting down the battery group and removing the double backup, and ensure the normal operation of the system when the system is activated during replacement or the charger is powered off or fails;

[0116] (4) Can be measured online or offline, connected between batteries as a battery bypass connection;

[0117] (5) High safety and good insulation, which can eliminate interference such as electromagnetic interference, ripple current, parasitic capacitance, etc.

[0118] (6) Ability to withstand high current discharge;

[0119] (7) Safe and reliable, with automatic identification and analysis of battery direction;

[0120] (8) A single deteriorated battery can be replaced online without shutting down the battery pack in operation;

[0121] (9) The instrument uses engineering plastic as its shell, which has good insulation performance and is safe and reliable to use.

[0122] IV. Application prospects of the present invention

[0123] The device of the present invention is used for online replacement of single-fault batteries in a battery pack, which can greatly improve the uninterruptible power supply guarantee capability; the single-battery jumper device adopts a unique circuit design and operation method, which can easily realize the replacement of faulty cells in the battery pack; if there is no suitable spare battery, the short circuit of the jumper device can also be temporarily used to replace the spare battery and the jumper; the present invention is connected according to the unique circuit design principle and fixed in a heat-insulating frame, and the frame is placed in a waterproof and sturdy box together with related tools and connecting wires; the online unit battery jumper does not need to exit the running battery pack, and a single deteriorated battery can be replaced online; at the same time, the single cell is compatible with 2V, 6V, and 12V, is safe and reliable, and the battery direction analysis is automatically identified; it is light in weight, easy to carry, and can replace batteries; in addition, the device is also equipped with a safe and simple wiring tool; when the battery pack is discharged, it can bridge the batteries that have reached the protection voltage, extend the discharge time to a certain extent, and protect the batteries connected at both ends of the battery.

[0124] Aiming at the problem that the battery pack has low voltage, even open circuit, heating and other emergency situations at the initial stage of discharge, and cannot continue the discharge detection, the present invention provides a novel non-stop replacement device for failed batteries of DC battery packs in substations, which is used for online replacement of single failed batteries of battery packs. The unique circuit design and operation method are adopted to conveniently replace failed units of battery packs. The present invention solves the unsafe hidden danger that the lagging batteries reduce the capacity of the whole group, so that the problem batteries (open circuit and failure) do not affect the safe operation of the equipment, and the battery capacity detection work can be carried out stably, orderly and conveniently. The present invention is suitable for all the current 500kV, 220kV, 110kV and 35kV substations, and has a wide range of applications. It is a reliable device for lagging batteries in substations, and has considerable application prospects.

Claims

1. A multifunctional replacement device for failed batteries of a DC battery pack in a substation, comprising a multifunctional battery junction box, characterized in that: A controller U1 is provided in the battery multifunctional junction box, the input end of the controller U1 is connected to a reference voltage unit for providing a reference voltage to the controller U1 and a measuring unit for measuring the battery voltage, and the input end of the measuring unit is connected to a battery short-circuiting unit; the output end of the controller U1 is connected to an optocoupler isolation drive circuit, and the output end of the optocoupler isolation drive circuit is connected to the input end of the battery short-circuiting unit.

2. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 1, characterized in that: The reference voltage unit includes a resistor R1, a resistor R3 connected in series with the resistor R1, and a capacitor C4 connected in parallel with the resistor R1; one end of the resistor R1 is grounded, and the other end is connected to the input end of the controller U1 and connected to a high level through the resistor R3.

3. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 2, characterized in that: The measuring unit includes resistors R7, R8 and a diode VD1; one end of the resistor R7 is connected to the input end of the controller U1, and the other end is grounded via the diode VD1 and connected to the anode of the thyristor VS via the resistor R8.

4. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 3, characterized in that: The multifunctional battery junction box also includes an alarm unit, which includes indicator lights H1, H2, and H3; the positive pole of the indicator light H1 is connected to a high level, and the negative pole is connected to the controller U1 via a resistor R4, and is connected to the cathode of the thyristor VS via the resistor R4; the alarm unit uses an indicator light to prompt the alarm.

5. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 4, characterized in that: The multifunctional battery junction box also includes an anti-error unit, which includes diodes VD2, VD3 and an optocoupler isolation module U2; the VCC terminal of the optocoupler isolation module U2 is connected to the power supply terminal Vcc, the GND terminal is grounded, the A terminal is connected to the power supply terminal Vcc via a resistor R2, the K terminal is connected to the P1.5 terminal of the controller U1, and the VO terminal is connected to the control electrode of the thyristor VS via a resistor R9.

6. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 5, characterized in that: The cathode of the diode VD2 is connected to the control electrode of the thyristor VS, and the anode is connected to the anode of the diode VD3.

7. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 6, characterized in that: The cathode of the diode VD3 is connected to the cathode of the thyristor VS, and the cathode is grounded; the cathode of the thyristor VS is connected to the negative electrode of the battery, and the anode is connected to the positive electrode of the battery.

8. A multifunctional replacement device for failed batteries of a DC storage battery pack in a substation as claimed in claim 5, characterized in that: The battery multifunctional junction box also includes a power supply unit, which includes a DC-DC power converter U3; the Vin- end of the DC-DC power converter U3 is connected to the negative electrode of the 12V high-performance lithium battery, and the Vin+ end is connected to the positive electrode of the 12V high-performance lithium battery via a fuse F1.

9. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 8, characterized in that: A polarity capacitor C1 and a capacitor C2 are provided between the Vin- terminal and the Vin+ terminal of the DC-DC power converter U3; a polarity capacitor C3 and a capacitor C5 are provided between the COM terminal and the Vo+ terminal of the DC-DC power converter U3; the positive electrode of the polarity capacitor C3 is connected to the power supply terminal Vcc, and the negative electrode is grounded.

10. A multifunctional replacement device for failed batteries of a DC battery pack in a substation as claimed in claim 8, characterized in that: The multifunctional battery junction box also includes a status display unit, which is composed of a detection circuit, a 16-bit A / D conversion module, a built-in 5PPM voltage reference source and an integrated board.

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