Auxiliary power system
By setting up a current limiting circuit and current limiting device in the factory power system to increase the line impedance, the problem of insufficient short-circuit resistance of high-end factories in the existing technology is solved, and the effect of low-cost and rapid transformation is achieved.
Patent Information
- Application Number
- CN202420420263.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-04
- Publication Date
- 2025-02-18
- Estimated Expiration
- 2034-03-04
AI Technical Summary
The existing methods to improve the short-circuit resistance of high-factory variables are costly and have a long transformation time, making it difficult to effectively solve the mechanical damage and temperature rise problems of factory power systems during short-circuit failures.
A factory power system is designed, including a power supply module, a power control module and a current limiting circuit. By setting up a current limiting device on the high-voltage side and the low-voltage side, the line impedance is increased and the short-circuit current is reduced.
It effectively improves the short-circuit resistance of the factory power system, reduces the impact of the short-circuit current on high-plant changes, and reduces the cost and time of transformation.
Smart Images
Figure CN222508783U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of factory electricity, in particular to a factory electricity system. Background Art
[0002] The high-voltage transformer of a power plant is an important electrical equipment that supplies electricity to the power plant for its own use. The high-voltage side is connected to the generator outlet and the low-voltage side of the main transformer. The voltage level of the low-voltage side is generally 6kV and 10kV. It is connected to the power load system of the power plant, including electrical equipment such as lines, high-voltage switch cabinets, and high-voltage auxiliary machines. When a short-circuit fault occurs in the line, high-voltage switch cabinet, or high-voltage auxiliary machine, the short-circuit current is very large, which will cause great mechanical damage and temperature rise to the winding. If it is not cut off or limited in time, the short-circuit current will cause problems such as winding deformation, winding insulation breakdown, and short-circuit burning. This is especially serious when the power protection device of the power plant refuses to operate, the incoming high-voltage switch, the auxiliary machine switch cannot be opened, or the switch itself has a short-circuit fault. Many high-voltage transformer damage incidents caused by short circuits in the nearby area indicate that the short-circuit resistance of some in-service high-voltage transformers is insufficient. The existing methods to improve the short-circuit resistance of high-voltage transformers include increasing the thickness of the core, increasing the width of the winding, using low-resistance and high-conductivity materials for the winding wire, and improving the internal insulation quality. These methods are costly and time-consuming to transform, and are not easy to implement and promote. Utility Model Content
[0003] In view of this, the utility model provides a factory power system to solve the problems of high cost and long transformation time in the existing method for improving the short-circuit resistance capability.
[0004] In a first aspect, the utility model provides a factory power system, the system comprising: a power supply module, a power control module and a current limiting circuit, wherein:
[0005] A power supply module, whose output end is connected to the input end of the current limiting circuit, and is used to provide high voltage to the current limiting circuit;
[0006] A power control module, whose input end is connected to the output end of the current limiting circuit, and whose output end is connected to the external electrical equipment, is used to control the current limiting circuit to output a low voltage to supply power to the external electrical equipment;
[0007] When the power control module or external electrical equipment is short-circuited to generate short-circuit current, and the power control module cannot disconnect the power supply to the external electrical equipment, the current limiting circuit is connected in series to increase the line impedance and reduce the current passing through the current limiting circuit.
[0008] The utility model provides an industrial power system, when a power control module or external electrical equipment has a short circuit fault and the power control module cannot be disconnected to supply power to the external electrical equipment, the line impedance is increased by a current limiting circuit to reduce the current of the line, thereby improving the short circuit resistance of the industrial power system. The current limiting circuit has a low cost and a simple structure, and is convenient for modifying the industrial power system.
[0009] In an optional implementation, the power control module includes: a master control switch and a plurality of single control switches, wherein:
[0010] A master control switch, one end of which is connected to the output end of the current limiting circuit, and the other end of which is connected to one end of the plurality of single control switches, for controlling whether the plurality of single control switches are powered on;
[0011] A single-control switch has one end connected to one end of the main control switch and the other end connected to an external electrical device, and is used to control whether the external electrical device connected to it is powered on.
[0012] The factory power system provided by the utility model controls the power supply to external electrical equipment by setting a master control switch and multiple single control switches. When a fault occurs, the corresponding single control switch and the master control switch are disconnected first, thereby ensuring the safety of the factory power system.
[0013] In an optional implementation, the current limiting circuit includes: a transformer and a plurality of current limiting devices, wherein:
[0014] A transformer, whose input end inputs high voltage, whose output end outputs low voltage, and whose grounding end is grounded, is used to convert the input high voltage into low voltage to supply power to external electrical equipment;
[0015] Multiple current limiting devices are installed at the input and output ends of the transformer respectively. When the short-circuit current is greater than a preset threshold, the current limiting devices are connected in series to the line to increase the line impedance and reduce the current passing through the current limiting circuit.
[0016] The utility model provides a factory power system, which limits the current in the line by arranging a plurality of current limiting devices at both ends of the transformer, thereby improving the short-circuit resistance of the transformer.
[0017] In an optional implementation, the transformer is a high-voltage transformer.
[0018] In an optional implementation, the power supply module is a generator.
[0019] The utility model provides a plant power system in which the generator directly provides power to the high-voltage transformer, thereby reducing the energy loss of the line. The cost of the high-voltage transformer is very high, and the cost of replacing the high-voltage transformer after the high-voltage transformer is damaged by short-circuit current is reduced by current limiting the high-voltage transformer.
[0020] In an optional implementation, the current limiting circuit further includes:
[0021] The first resistor has a first end connected to the ground terminal of the transformer and a second end connected to the ground.
[0022] The utility model provides a power supply system for a factory, which avoids the occurrence of electrical accidents and ensures the safety of people and the power supply system for a factory by connecting a resistor in series at the grounding end of the transformer.
[0023] In an optional embodiment, the current limiting device includes: a high-pressure side current limiting device and a low-pressure side current limiting device, wherein:
[0024] A high-voltage side current limiting device, whose input end is input with high voltage and whose output end is connected to the input end of the transformer, is used for increasing its impedance to reduce the current passing through the current limiting circuit when the short-circuit current is greater than a first preset threshold value;
[0025] A low-voltage side current limiting device, whose input end is connected to the output end of the transformer and whose output end outputs low voltage, is used for increasing its impedance to reduce the current passing through the current limiting circuit when the short-circuit current is greater than the second preset threshold and less than the first preset threshold.
[0026] The utility model provides a plant power system, which limits the impact of short-circuit current in the vicinity on the high-voltage plant transformer by setting current limiting devices with different thresholds on the low-voltage side and the high-voltage side, thereby enhancing the short-circuit resistance of the plant power system when a short circuit occurs in the vicinity of the high-voltage plant transformer.
[0027] In an optional implementation, the current limiting device includes: a first switch, a second switch, and a reactor, wherein:
[0028] The first switch forms a first branch;
[0029] The second switch is connected in series with the reactor to form a second branch, and the first branch is connected in parallel with the second branch;
[0030] When the current passing through the current limiting device is less than a preset threshold, the first switch is closed and the second switch is opened; when the current passing through the current limiting device is greater than the preset threshold, the first switch is opened and the second switch is closed.
[0031] The utility model provides a factory power system, which sets two branches of a current limiting device, switches the two branches according to actual current values, changes the reactance in the line, thereby limiting the current in the line and preventing short-circuit current from damaging equipment in the factory power system. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0033] Figure 1 It is a structural diagram of the existing plant power system;
[0034] Figure 2It is a structural schematic diagram of a factory power system according to an embodiment of the utility model;
[0035] Figure 3 It is a structural schematic diagram of a specific embodiment of a plant power system according to an embodiment of the utility model;
[0036] Figure 4 It is a structural schematic diagram of a current limiting device in a factory power system according to an embodiment of the utility model. DETAILED DESCRIPTION
[0037] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.
[0038] The existing power plant power system is as follows Figure 1 As shown, it includes: high-voltage power transformer, lines, power control switches, generators and high-voltage switchgear, high-voltage auxiliary equipment and other electrical equipment. When a single-phase ground short circuit or phase-to-phase short circuit occurs somewhere in the power load system, if the line switch K1 serving as the main switch in the line and the branch switches (K2, K3, K4, K5) where the short-circuit point is located cannot be disconnected in time or the switch itself has a short-circuit fault, the short-circuit current will have an impact on the high-voltage power transformer.
[0039] An embodiment of the present invention provides a plant power system, in which current limiting devices are respectively arranged on the high-voltage side and the low-voltage side of a high-voltage plant transformer in the plant power system to improve the short-circuit resistance of the high-voltage plant transformer at a low cost.
[0040] According to an embodiment of the utility model, a factory power system embodiment is provided. Figure 2 Schematic diagram of the structure of the power supply system of the plant according to the embodiment of the utility model, such as Figure 2 As shown, the system includes: a power supply module 1, a power control module 2 and a current limiting circuit 3, wherein:
[0041] The power supply module 1 has an output end connected to the input end of the current limiting circuit 3 and is used to provide high voltage to the current limiting circuit 3 .
[0042] In some optional embodiments, the power supply module 1 is a generator.
[0043] In the plant power system provided in this embodiment, the generator directly provides power to the high-voltage transformer, reducing the energy loss of the line. The cost of the high-voltage transformer is very high. By limiting the current of the high-voltage transformer, the cost of replacing the high-voltage transformer after it is damaged by short-circuit current is reduced.
[0044] The power consumption control module 2 has an input end connected to the output end of the current limiting circuit 3 and an output end connected to an external electrical device, and is used to control the current limiting circuit 3 to output a low voltage to supply power to the external electrical device.
[0045] When the power control module 2 or external electrical equipment is short-circuited to generate short-circuit current, and the power control module 2 cannot be disconnected to supply power to the external electrical equipment, the current limiting circuit 3 is connected in series to increase the line impedance and reduce the current passing through the current limiting circuit.
[0046] Specifically, when a short-circuit fault occurs in an external electrical device, generating a short-circuit current, and the power control module fails and cannot control the disconnection of power supply to the external electrical device, if no measures are taken, the short-circuit current will enter the line where the current limiting circuit is located and damage the equipment. After adding the current limiting circuit, when a short-circuit current is generated, the current limiting circuit is controlled to connect impedance to the line to increase the impedance in the line and reduce the current.
[0047] The factory power system provided in this embodiment increases the line impedance and reduces the line current through a current limiting circuit when a power control module or external electrical equipment has a short-circuit fault and the power control module cannot disconnect the power supply to the external electrical equipment, thereby improving the short-circuit resistance of the factory power system. The current limiting circuit has a low cost and a simple structure, and is easy to modify the factory power system.
[0048] In some optional embodiments, such as Figure 3 As shown, the power control module 2 includes: a master control switch 21 and a plurality of single control switches 22, wherein:
[0049] A master control switch 21, one end of which is connected to the output end of the current limiting circuit, and the other end of which is connected to one end of the plurality of single control switches 22, for controlling whether the plurality of single control switches 22 are powered on;
[0050] The single-control switch 22 has one end connected to one end of the master control switch 21 and the other end connected to an external electrical device, and is used to control whether the external electrical device connected thereto is powered on.
[0051] Specifically, the external electrical equipment and the power control module 2 together constitute the factory power load system. The master control switch 21 is the incoming line switch of the external electrical equipment, and the single control switch 22 is the high-voltage auxiliary machine switch of the external electrical equipment. The external electrical equipment is a high-voltage switch cabinet, a high-voltage auxiliary machine, etc., which is only taken as an example, but not limited to this.
[0052] The factory power system provided in this embodiment controls the power supply to external electrical equipment by setting a master control switch and multiple single control switches. When a fault occurs, the corresponding single control switch and the master control switch are disconnected first, thereby ensuring the safety of the factory power system.
[0053] In some optional embodiments, such as Figure 3 As shown, the current limiting circuit 3 includes: a transformer 31 and a plurality of current limiting devices, the current limiting devices include: a high-voltage side current limiting device 321 and a low-voltage side current limiting device 322, wherein:
[0054] The transformer 31 has a high voltage input at its input end, a low voltage output at its output end, and a grounding end connected to ground, and is used to convert the input high voltage into a low voltage to supply power to external electrical equipment. Specifically, the transformer 31 is a high-voltage transformer.
[0055] A plurality of current limiting devices are respectively installed at the input and output ends of the transformer 31. When the short-circuit current is greater than a preset threshold, the current limiting devices are connected in series to the line to increase the line impedance and reduce the current passing through the current limiting circuit.
[0056] Specifically, at least one current limiting device is connected to the high-pressure side and the low-pressure side of the high-voltage transformer. Here, it is taken as an example that each side is connected to one current limiting device, but the present invention is not limited thereto.
[0057] The high-voltage side current limiting device 321 has a high voltage input at its input end and an output end connected to the input end of the transformer 31. When the short-circuit current is greater than a first preset threshold, the high-voltage side current limiting device 321 increases its impedance to reduce the current passing through the current limiting circuit.
[0058] The low-voltage side current limiting device 322 has an input end connected to the output end of the transformer 31 and an output end outputting a low voltage. When the short-circuit current is greater than the second preset threshold and less than the first preset threshold, the low-voltage side current limiting device 322 increases its impedance to reduce the current passing through the current limiting circuit.
[0059] The plant power system provided in this embodiment limits the impact of short-circuit current in the vicinity on the high-voltage plant transformer by setting current limiting devices with different thresholds on the low-voltage side and the high-voltage side, thereby enhancing the short-circuit resistance of the plant power system when a short circuit occurs in the vicinity of the high-voltage plant transformer.
[0060] Specifically, when a short-circuit fault occurs in the plant power load system on the low-voltage side of the high-voltage transformer, the plant power protection device refuses to operate, the incoming high-voltage switch and auxiliary switch cannot be opened, or the switch itself has a short-circuit fault, the short-circuit current in the line is greater than the current during normal operation. If the short-circuit current is less than the maximum short-circuit current that the low-voltage side of the high-voltage transformer can withstand, the reactor in the current limiting device on the low-voltage side is put into operation; if the short-circuit current is greater than the maximum short-circuit current that the low-voltage side of the high-voltage transformer can withstand, the reactors in the current limiting devices on the high-voltage and low-voltage sides are put into operation at the same time, which effectively limits the short-circuit current, reduces the electromagnetic force and temperature rise on the high-voltage transformer winding, and promptly avoids damage to the high-voltage transformer caused by winding deformation and winding short-circuit.
[0061] The auxiliary power system provided in this embodiment limits the current in the line by arranging a plurality of current limiting devices at both ends of the transformer, thereby improving the short-circuit resistance of the transformer.
[0062] In some optional embodiments, such as Figure 3 As shown, the current limiting circuit 3 also includes:
[0063] The first resistor R1 has a first end connected to the ground terminal of the transformer 31 and a second end connected to the ground.
[0064] Specifically, a resistor is connected in series at the grounding end of the transformer 31, so that a part of the fault current can be introduced into the ground, thereby reducing the fault current and thus reducing the loss.
[0065] The auxiliary power system provided in this embodiment avoids the occurrence of electrical accidents by inserting a resistor in series at the grounding terminal of the transformer, thereby ensuring the safety of personnel and the auxiliary power system.
[0066] In some optional embodiments, such as Figure 4 As shown, the current limiting device includes: a first switch K6, a second switch K7, and a reactor L, wherein:
[0067] The first switch K6 forms a first branch.
[0068] The second switch K7 is connected in series with the reactor L to form a second branch, and the first branch is connected in parallel with the second branch.
[0069] Specifically, the first switch K6 is an incoming line switch, and the second switch K7 is a high-voltage auxiliary machine switch, which is only taken as an example, but not limited to this. The reactor is a device that can achieve current limiting, and can also be a resistor. Here, the reactor is taken as an example, but not limited to this.
[0070] When the current passing through the current limiting device is less than the preset threshold, the first switch K6 is closed and the second switch K7 is opened. When the current passing through the current limiting device is greater than the preset threshold, the first switch K6 is opened and the second switch K7 is closed.
[0071] The factory power system provided in this embodiment sets two branches of the current limiting device, switches the two branches according to the actual current value, changes the reactance in the line, thereby limiting the current in the line and preventing short-circuit current from damaging equipment in the factory power system.
[0072] Specifically, Figure 3 In the plant power system shown in the figure, taking the 6kV plant power system as an example, the actual maximum short-circuit current on the low-voltage side of the high-voltage plant transformer can reach 40kA. In the short-circuit strength calculation report provided by the manufacturer, the short-circuit current on the low-voltage side of the high-voltage plant transformer is 15.44k. When a short-circuit fault occurs somewhere in the plant power load system (that is, the power control module and its connected external electrical equipment), the current limiting of the plant power system is carried out from the following aspects:
[0073] (1) If the incoming line switch K1 and the high-voltage auxiliary machine switch (K2-K5) operate normally and open, the high-voltage side current limiting device and the low-voltage side current limiting device on both sides of the high-voltage transformer will not be put into use, that is, the high-voltage side current limiting device and the low-voltage side current limiting device will not operate, and the first switch K6 of the high-voltage side current limiting device and the low-voltage side current limiting device will be closed and the second switch K7 will be opened;
[0074] (2) If a short circuit occurs in the high-voltage auxiliary equipment and the connecting line, the incoming line switch K1 operates normally and opens, and the high-voltage auxiliary equipment switches (K2-K5) refuse to operate and do not open, then the high-voltage side current limiting devices and the low-voltage side current limiting devices on both sides of the high-voltage transformer are not put into use, and the first switch K6 of the high-voltage side current limiting device and the low-voltage side current limiting device is closed, and the second switch K7 is opened;
[0075] (3) If a short circuit occurs in the high-voltage auxiliary equipment and the connecting line, the incoming line switch K1 refuses to operate and does not open, and the high-voltage auxiliary equipment switches (K2-K5) refuse to operate and do not open, the action of the current limiting device connected to the circuit is determined according to the magnitude of the short-circuit current, as follows:
[0076] a. If the short-circuit current is greater than the second preset threshold value and less than the first preset threshold value, the low-voltage side current limiting device of the high-voltage transformer is put into use, and the high-voltage side current limiting device of the high-voltage transformer is not put into use. The first switch K6 of the low-voltage side current limiting device is disconnected and the second switch K7 is closed. The first switch K6 of the high-voltage side current limiting device is closed and the second switch K7 is disconnected. Here, the first preset threshold value is the normal current size in the line when the plant power system and the plant power load system are working normally (the specific size is calculated according to the actual situation, and the calculation method is not limited). The second preset threshold value is the short-circuit circuit threshold value of the high-voltage transformer set by the manufacturer (15.44kA, for example only, but not limited thereto);
[0077] b. If the short-circuit current is greater than the first preset threshold, the low-voltage side current limiting device and the high-voltage side current limiting device of the high-voltage transformer are put into use at the same time, the first switch K6 of the low-voltage side current limiting device is disconnected, the second switch K7 is closed, and the first switch K6 of the high-voltage side current limiting device is disconnected, and the second switch K7 is closed;
[0078] When a short circuit occurs on the 6kV busbar, the incoming switch K1 operates normally and opens, then the high-voltage side current limiting device and the low-voltage side current limiting device on both sides of the high-voltage transformer are not put into use, the first switch K6 of the high-voltage side current limiting device and the low-voltage side current limiting device is closed, and the second switch K7 is opened; when a short circuit occurs on the 6kV busbar or a short circuit occurs on the incoming switch K1, the incoming switch refuses to operate and does not open, then the action of the current limiting device is determined according to the size of the short-circuit current, as follows:
[0079] c. If the short-circuit current is greater than the second preset threshold value and less than the first preset threshold value, the low-voltage side current limiting device of the high-voltage transformer is put into use, and the high-voltage side current limiting device of the high-voltage transformer is not put into use. The first switch K6 of the low-voltage side current limiting device is disconnected and the second switch K7 is closed, and the first switch K6 of the high-voltage side current limiting device is closed and the second switch K7 is disconnected. Here, the first preset threshold value is the normal current size in the line when the plant power system and the plant power load system are working normally (the specific size is calculated according to the actual situation, and the calculation method is not limited), and the second preset threshold value is the short-circuit circuit threshold value of the high-voltage transformer set by the manufacturer (15.44kA, for example only, but not limited thereto);
[0080] d. If the short-circuit current is greater than the first preset threshold, the low-voltage side current limiting device and the high-voltage side current limiting device of the high-voltage transformer are put into use at the same time, the first switch K6 of the low-voltage side current limiting device is disconnected and the second switch K7 is closed, and at the same time, the first switch K6 of the high-voltage side current limiting device is disconnected and the second switch K7 is closed.
[0081] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.
Claims
1. A factory power system, characterized in that: The system includes: a power supply module, a power consumption control module and a current limiting circuit, wherein: A power supply module, whose output end is connected to the input end of the current limiting circuit, and is used to provide high voltage for the current limiting circuit; A power control module, whose input end is connected to the output end of the current limiting circuit, and whose output end is connected to an external electrical device, and is used to control the current limiting circuit to output a low voltage to supply power to the external electrical device; When the power control module or the external electrical device is short-circuited to generate a short-circuit current, and the power control module cannot disconnect the power supply to the external electrical device, the current limiting circuit is connected in series to increase the line impedance and reduce the current passing through the current limiting circuit.
2. The system according to claim 1, characterized in that The power control module includes: a master control switch and multiple single control switches, wherein: A master control switch, one end of which is connected to the output end of the current limiting circuit, and the other end of which is connected to one end of the plurality of single control switches, for controlling whether the plurality of single control switches are powered on; A single-control switch, one end of which is connected to one end of the master control switch, and the other end of which is connected to one of the external electrical devices, is used to control whether the external electrical device connected thereto is powered on.
3. The system according to claim 1, characterized in that The current limiting circuit comprises: a transformer and a plurality of current limiting devices, wherein: A transformer, whose input end inputs high voltage, whose output end outputs low voltage, and whose grounding end is grounded, is used to convert the input high voltage into low voltage to supply power to external electrical equipment; A plurality of current limiting devices are respectively installed at the input end and the output end of the transformer. When the short-circuit current is greater than a preset threshold, the current limiting device is connected in series to the line to increase the line impedance and reduce the current passing through the current limiting circuit.
4. The system according to claim 3, characterized in that The transformer is a high-voltage transformer.
5. The system according to claim 3, characterized in that The power supply module is a generator.
6. The system according to claim 3, characterized in that The current limiting circuit further includes: A first resistor has a first end connected to the ground terminal of the transformer and a second end connected to the ground.
7. The system according to claim 3, characterized in that The current limiting device comprises: a high-pressure side current limiting device and a low-pressure side current limiting device, wherein: A high-voltage side current limiting device, whose input end is input with high voltage and whose output end is connected to the input end of the transformer, is used for increasing its impedance to reduce the current passing through the current limiting circuit when the short-circuit current is greater than a first preset threshold value; A low-voltage side current limiting device, whose input end is connected to the output end of the transformer and whose output end outputs low voltage, is used for increasing its impedance to reduce the current passing through the current limiting circuit when the short-circuit current is greater than the second preset threshold and less than the first preset threshold.
8. The system according to claim 3, characterized in that The current limiting device includes: a first switch, a second switch, and a reactor, wherein: The first switch forms a first branch; The second switch is connected in series with the reactor to form a second branch, and the first branch is connected in parallel with the second branch; When the current passing through the current limiting device is less than a preset threshold, the first switch is closed and the second switch is opened; when the current passing through the current limiting device is greater than the preset threshold, the first switch is opened and the second switch is closed.