Multi-protection self-adaptive analog quantity starting power supply fast switching system

Abstract

The invention relates to the technical field of power supply protection, in particular to a multi-protection self-adaptive analog quantity starting power supply rapid switching system. The system comprises a 6 / 10kV bus coupler quick switching device, a re-voltage starting direction over-current starting module for detecting whether a reverse power condition exists, a frequency voltage starting module for detecting whether voltage and frequency abnormity exists, a low-frequency no-current starting module for detecting whether current and frequency abnormity exists, and a bus coupler quick switching device, the directional overcurrent low-voltage starting module is used for detecting whether voltage abnormity exists or not; and if the reverse power or the abnormality exists, the 6 / 10kV bus coupler quick switching device starts control to disconnect the fault line with the reverse power or the abnormality, and meanwhile, the line between the electric equipment corresponding to the non-fault line and the fault line is connected. The problems that an original power supply rapid switching device is single in analog quantity starting mode, poor in applicability and poor in capability of identifying voltage sag of an external network of a power supply system, so that the power supply system cannot rapidly send a switching command to execute power supply rapid switching are solved.

Description

Technical Field

[0001] The invention relates to the technical field of power supply protection, and in particular to a multi-protection adaptive analog quantity starting power supply fast switching system. Background Art

[0002] The power system power rapid switching device is an important technical measure to resist power shaking in the power system of refining and chemical enterprises. When the power supply system fault causes a temporary voltage drop, whether the power rapid switching device can play a role depends on the performance of the analog startup method with rapid identification of different fault capabilities of the external network.

[0003] In order to achieve rapid and disturbance-free switching of power supply when the power supply system fails and the voltage drops temporarily, the use of adaptive multiple analog startup methods is a practical key technical measure. Although the current power supply fast switching device on the market has several analog startup methods, some analog startup methods cannot be used because the device only collects analog parameters of one voltage level of the power system.

[0004] When the user has his own generator set, synchronous motor set and power rapid switching device connected to the user's main transformer secondary low-voltage system, the reverse power analog starting mode of the power rapid switching device has poor applicability to the generator set grid-connected voltage level and cannot be put into use. However, the non-generator set grid-connected voltage level on the primary side of the user's power incoming main transformer requires the reverse power analog starting mode. When the user's generator set is connected to the grid and a serious short circuit fault occurs in the external power supply system, causing a temporary voltage drop, the fastest reverse power analog starting mode is not used in this fault situation, and the power rapid switching device does not start switching in the first time, failing to meet the technical requirements of rapid identification and switching.

[0005] The existing method of effectively starting and automatically switching power when the voltage drops due to external network faults in the power supply system can effectively start when the voltage drops due to external network faults, but it is not the fastest starting method for some fault types. As a result, when the voltage drops due to certain faults, the power switching command cannot be issued immediately to execute the power supply fast switching, affecting the safe and stable operation of the production equipment. Summary of the invention

[0006] The present invention proposes a multi-protection adaptive analog quantity starting power supply rapid switching system to solve the defects of the original power supply rapid switching device, such as single analog quantity starting mode and poor applicability, and poor ability to identify temporary voltage drop of the power supply system external network, resulting in the inability to quickly issue a switching command to execute power supply rapid switching.

[0007] According to one aspect of the present invention, there is provided a multi-protection adaptive analog quantity starting power supply fast switching system, comprising: a 6 / 10kV busbar fast switching device; The 6 / 10kV busbar quick-cut device is respectively connected to the re-voltage starting direction overcurrent starting module, the frequency-voltage starting module, the low-frequency no-current starting module, the direction overcurrent low-voltage starting module and the power supply line; When the overcurrent starting module in the re-pressure starting direction detects that one of the two power supply lines has reverse power, it determines whether the power shake is caused by a short circuit fault of the external network or the upper adjacent line. If so, the power supply line is a faulty line; When the frequency-voltage startup module detects that one of the two power supply lines has abnormal voltage and frequency, it determines whether it is a remote power grid fault or a power generation enterprise and power grid disconnection fault. If so, the power supply line is a faulty line; When the low-frequency no-current starting module detects that the current and frequency of one of the two power supply lines are abnormal, it is determined that the upper switch of the external power supply line is tripped, and the power supply line is a faulty line; When the directional overcurrent low voltage starting module detects that there is a voltage abnormality in one of the two power supply lines, it is determined whether it is an external fault of the power supply system. If so, the power supply line is a faulty line; The 6 / 10kV busbar quick-cut device starts controlling to disconnect the faulty line, and at the same time connects the line between the non-faulty line and the electrical equipment corresponding to the faulty line.

[0008] Preferably, the determining whether the power fluctuation is caused by a short circuit fault in an external network or an upper adjacent line includes: Determine whether one of the line voltages between the three phases in the power supply line is less than the first voltage threshold value, or whether the negative sequence voltage in the power supply line is greater than the second voltage threshold value. If so, when reverse power occurs in the power supply line, it is a power shake caused by a short circuit fault in the external network or the upper adjacent line.

[0009] Preferably, the voltage and frequency anomalies are: If the line voltages between the three phases in the power supply line are greater than the first predetermined voltage setting and the frequency is greater than the predetermined high frequency setting, or the line voltages between the three phases in the power supply line are less than the second predetermined voltage setting and the frequency is less than the predetermined low frequency setting, then the voltage and frequency are abnormal.

[0010] Preferably, the determining whether it is a remote power grid fault or a power generation enterprise disconnection fault from the power grid includes: It is determined whether the minimum voltage in the power supply line is greater than a predetermined voltage range, and whether the current value of the power supply line is less than a predetermined current value. If so, it is a remote power grid fault or a power generation enterprise disconnection fault from the power grid.

[0011] Preferably, the current and frequency anomalies are: If the current value in the power supply line is less than a predetermined no-current set value, and the frequency is less than a predetermined low-frequency set value, the current and frequency are abnormal.

[0012] Preferably, the low-frequency no-current starting module further includes: When the low-frequency no-current starting module detects that there is current and frequency abnormality in one of the two power supply lines, it simultaneously determines whether the maximum voltage in the power supply line is less than 90V. If so, it means that the upper switch of the external network power supply line has tripped.

[0013] Preferably, the voltage anomaly is: If the line voltages between the three phases in the power supply line are all less than the set values, it is the voltage abnormality.

[0014] Preferably, the determining whether it is an external fault of the power supply system includes: Determine whether the maximum current value in the power supply line is less than the directional overcurrent blocking value, and the direction is pointing to the load side. If so, it is an external fault of the power supply system.

[0015] Preferably, it also includes: a non-directional overcurrent low voltage starting module; The non-directional overcurrent low-voltage starting module is connected to the 6 / 10kV bus fast-cut device; When the non-directional overcurrent low-voltage starting module detects that the line voltages between the three phases of one of the two power supply lines are all lower than the set value, it determines whether the voltage drop is not caused by the startup of the electrical equipment. If so, the 6 / 10kV busbar quick-cutting device controls the disconnection of the faulty line, and at the same time connects the line between the non-fault line and the electrical equipment corresponding to the faulty line.

[0016] Preferably, the determining whether the voltage drop is not caused by the startup of the electrical equipment includes: Determine whether the maximum current value in the power supply line is less than the overcurrent shutdown setting value. If so, the voltage drop is not caused by the startup of the electrical equipment.

[0017] The present invention has at least the following beneficial effects: The present invention proposes a multi-protection adaptive analog starting power supply fast switching system, which adopts a modular combination method and is composed of a plurality of protection devices and a power supply fast switching device. It can realize effective fast starting and automatic power supply switching when voltage drops are caused by all faults in the external network of the power supply system, and truly improve the ability to resist external network power shaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present invention and, together with the specification, are used to explain the technical solutions of the present invention.

[0019] Figure 1 A schematic diagram showing the structure of a multi-protection adaptive analog quantity starting power supply fast switching system according to an embodiment of the present invention is shown; Figure 2 A control principle diagram of an overcurrent starting module in a re-pressure starting direction according to an embodiment of the present invention is shown; Figure 3 A control principle diagram of a frequency-voltage startup module according to an embodiment of the present invention is shown; Figure 4 A control principle diagram of a low-frequency no-current starting module according to an embodiment of the present invention is shown; Figure 5 A control principle diagram of a directional overcurrent low voltage startup module according to an embodiment of the present invention is shown; Figure 6 A control principle diagram of a non-directional overcurrent low-voltage startup module according to an embodiment of the present invention is shown. Implementation

[0020] Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0021] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0022] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0023] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0024] Figure 1 A schematic diagram showing the structure of a multi-protection adaptive analog quantity starting power supply fast switching system according to an embodiment of the present invention is shown; Figure 2 A control principle diagram of an overcurrent starting module in a re-pressure starting direction according to an embodiment of the present invention is shown; Figure 3 A control principle diagram of a frequency-voltage startup module according to an embodiment of the present invention is shown; Figure 4 A control principle diagram of a low-frequency no-current starting module according to an embodiment of the present invention is shown; Figure 5 A control principle diagram of a directional overcurrent low voltage startup module according to an embodiment of the present invention is shown; Figure 6 FIG. 2 shows a control principle diagram of a non-directional overcurrent low voltage startup module according to an embodiment of the present invention. Figure 1-6 As shown, a multi-protection adaptive analog starting power supply fast switching system includes: a 6 / 10kV busbar fast switching device; the 6 / 10kV busbar fast switching device is respectively connected to a re-voltage starting direction overcurrent starting module, a frequency-voltage starting module, a low-frequency no-current starting module, a direction overcurrent low-voltage starting module and a power supply line; when the re-voltage starting direction overcurrent starting module detects that one of the two power supply lines has a reverse power situation, it determines whether it is a power shake caused by a short circuit fault of an external network or an upper adjacent line. If so, the power supply line is a faulty line; when the frequency-voltage starting module detects that one of the two power supply lines has a voltage and frequency anomaly, it determines whether it is If there is a remote power grid fault or a power generation enterprise is disconnected from the power grid, the power supply line is a faulty line; when the low-frequency no-current starting module detects that one of the two power supply lines has current and frequency abnormalities, it is determined that the upper switch of the external power supply line has tripped, and the power supply line is a faulty line; when the directional overcurrent low-voltage starting module detects that one of the two power supply lines has voltage abnormalities, it is determined whether it is an external fault of the power supply system, and if so, the power supply line is a faulty line; the 6 / 10kV busbar fast-cutting device starts and controls to disconnect the faulty line, and at the same time connects the line between the non-fault line and the electrical equipment corresponding to the faulty line.

[0025] In an embodiment of the present invention, the incoming line voltage level of the user's main substation is 35KV, 66KV or 110KV, and the 35 / 66 / 110kV power supply system is respectively provided with two sections of power supply, including section I power bus and section II power bus; section I power bus is connected to the corresponding motor and other electrical equipment through the power supply line I composed of 35 / 66 / 110kV#1 incoming line switch, #1 main transformer and 6 / 10kV#1 incoming line switch; section II power bus is connected to the corresponding motor and other electrical equipment through the power supply line II composed of 35 / 66 / 110kV#2 incoming line switch, #2 main transformer and 6 / 10kV#2 incoming line switch, the main transformer is a two-turn transformer or a three-turn transformer, and the secondary side voltage level of the main transformer is 6kV or 10kV.

[0026] The 6 / 10kV bus coupler quick-cut device is respectively connected to power supply line I, power supply line II, 35 / 66 / 110kV#1 incoming line switch, 35 / 66 / 110kV#2 incoming line switch, 6 / 10kV#1 incoming line switch and 6 / 10kV#2 incoming line switch. At the same time, the line between the 6 / 10kV#1 incoming line switch and the corresponding power equipment, as well as the line between the 6 / 10kV#2 incoming line switch and the corresponding power equipment, are respectively connected to the 6 / 10kV bus coupler quick-cut device through the 6 / 10kV bus coupler switch.

[0027] The 6 / 10kV busbar quick-cut device is connected to two 35 / 66 / 110kV incoming line protection devices respectively. Each 35 / 66 / 110kV incoming line protection device contains the corresponding re-voltage start direction overcurrent start module, frequency voltage start module, low frequency no current start module and direction overcurrent low voltage start module. The two 35 / 66 / 110kV incoming line protection devices are connected to their corresponding power supply lines respectively.

[0028] During the operation of the power supply system, in the initial state, the 35 / 66 / 110kV#1 incoming line switch, 35 / 66 / 110kV#2 incoming line switch, 6 / 10kV#1 incoming line switch and 6 / 10kV#2 incoming line switch are in the closed state, and the 6 / 10kV bus tie switch is in the open state.

[0029] The overcurrent start module in the re-voltage start direction detects the current direction and voltage parameter changes on the primary side of the main transformer in the corresponding power supply line in real time. When reverse power occurs in power supply line I or power supply line II, it can be judged that the reverse power is caused by the power shake caused by the short circuit fault of the external network or the upper adjacent line. Then the overcurrent start module in the re-voltage start direction will send a power switching signal to the 6 / 10kV busbar fast-cut device. At the same time, the faulty 35 / 66 / 110kV#1 incoming line switch or 35 / 66 / 110kV#2 incoming line switch is controlled to trip.

[0030] The frequency-voltage start module detects the voltage and frequency of the primary side of the main transformer in the corresponding power supply line in real time. When the voltage and frequency of power supply line I or power supply line II are abnormal, it can be judged that the voltage and frequency abnormality is caused by a remote power grid fault or power grid decoupling. Then the frequency-voltage start module will send a power switching signal to the 6 / 10kV busbar quick-cut device. At the same time, the faulty 35 / 66 / 110kV#1 incoming line switch or 35 / 66 / 110kV#2 incoming line switch will be controlled to trip.

[0031] The low-frequency no-current starting module detects the current and frequency of the primary side of the main transformer in the corresponding power supply line in real time. When the current and frequency of power supply line I or power supply line II are abnormal, it can be judged that the current and frequency abnormality is caused by the upper switch of the external power supply line. Then the low-frequency no-current starting module will send a power switching signal to the 6 / 10kV bus fast-cut device. At the same time, it controls the faulty 35 / 66 / 110kV#1 incoming line switch or 35 / 66 / 110kV#2 incoming line switch to trip.

[0032] The directional overcurrent low voltage start module detects the voltage value of the primary side of the main transformer in the corresponding power supply line in real time. When the voltage is abnormal and it is judged that the voltage abnormality is not caused by the internal fault of the power supply system, the low-frequency no-current start module will send a power switching signal to the 6 / 10kV bus fast-cut device. At the same time, the faulty 35 / 66 / 110kV#1 incoming line switch or 35 / 66 / 110kV#2 incoming line switch will be controlled to trip.

[0033] When power supply line Ⅰ fails due to power shaking, the 6 / 10kV busbar quick-cut device receives the #1 power switching signal and controls the faulty line, that is, the 6 / 10kV #1 incoming line switch on power supply line Ⅰ is tripped, disconnecting the line between section Ⅰ power bus and the corresponding power-consuming equipment. At the same time, the 6 / 10kV busbar switch is controlled to close, connecting the line between the 6 / 10kV #2 incoming line switch and the power-consuming equipment corresponding to power supply line Ⅰ, thereby supplying power to the power-consuming equipment corresponding to power supply line Ⅰ through section Ⅱ power bus and power supply line Ⅱ, ensuring the normal operation of the power-consuming equipment.

[0034] When power supply line II fails due to power shaking, the 6 / 10kV busbar quick-cut device receives the #2 power switching signal and controls the faulty line, that is, the 6 / 10kV #2 incoming line switch on power supply line II is tripped, disconnecting the line between section II power bus and the corresponding power-consuming equipment. At the same time, the 6 / 10kV busbar switch is controlled to close, connecting the line between the 6 / 10kV #1 incoming line switch and the power-consuming equipment corresponding to power supply line II, thereby supplying power to the power-consuming equipment corresponding to power supply line I through section I power bus and power supply line II, ensuring the normal operation of the power-consuming equipment.

[0035] In the present invention, the judgment of whether the power fluctuation is caused by a short circuit fault in the external network or an upper adjacent line includes: judging whether one of the line voltages between the three phases in the power supply line is less than a first voltage threshold value, or whether the negative sequence voltage in the power supply line is greater than a second voltage threshold value; if so, when a reverse power condition occurs in the power supply line, the power fluctuation is caused by a short circuit fault in the external network or an upper adjacent line.

[0036] In the embodiment of the present invention, the re-voltage starting directional overcurrent starting module includes directional overcurrent protection, low voltage protection and overvoltage protection.

[0037] The directional overcurrent protection is used to detect in real time whether one or more of the three-phase lines A, B, and C on the primary side of the main transformer of the corresponding power supply line has reverse power; the low voltage protection is used to detect in real time the line voltage U between the three phases on the primary side of the main transformer of the corresponding power supply line. AB , U BC , U CA Whether one or more of them is less than the first voltage threshold value; the overvoltage protection is used to detect in real time whether the negative sequence voltage U2 on the primary side of the main transformer in the power supply line is greater than the second voltage threshold value.

[0038] like Figure 2 As shown, ≥ is or, δ is and. When the directional overcurrent protection corresponding to the power supply line I or the power supply line II detects that the power supply line has reverse power, it means that the power supply line I or the power supply line II has an abnormality. At the same time, the low voltage protection detects that one of the line voltages between the three phases on the primary side of the main transformer is less than the first voltage threshold value, or the overvoltage protection detects that the negative sequence voltage is greater than the second voltage threshold value, then the corresponding 35 / 66 / 110kV#1 incoming line switch on the power supply line I or the 35 / 66 / 110kV#2 incoming line switch on the power supply line II where reverse power occurs is cut off (tripped), and at the same time, a power switching signal is sent to the busbar fast-cut device to cut off (trip) the corresponding 6 / 10kV#1 incoming line switch on the power supply line I or the 6 / 10kV#2 incoming line switch on the power supply line II, that is, disconnect (trip) the fault line, and at the same time control the 6 / 10kV busbar switch to close, and supply power through the non-fault power supply line I or power supply line II.

[0039] When reverse power occurs in the power supply line, if the reverse power is caused by power swing due to a short circuit fault of the external network or the upper adjacent line, the line voltage between the three phases of the power supply line will be lower than the first voltage threshold value, or the negative sequence voltage U2 will be greater than the second voltage threshold value; if it is not a short circuit fault of the external network or the upper adjacent line, but an internal fault of the system, it will be positive power instead of reverse power; the re-voltage starting direction overcurrent starting module uses the directional current module to determine whether the reverse power is abnormally caused by a short circuit fault of the external network or the upper adjacent line. By increasing the three-phase voltage and negative sequence voltage judgment criteria, the accuracy of the reverse power starting method caused by the short circuit fault of the external network or the upper adjacent line is improved, thereby preventing the 6 / 10kV busbar quick-cut device from starting incorrectly.

[0040] When starting, the overcurrent starting module in the re-pressure starting direction needs to detect whether the circuit breaker closing current of the incoming switch, the low voltage protection input pressure plate, the overvoltage protection input pressure plate and the overcurrent starting module in the re-pressure starting direction (overcurrent protection input pressure plate in the re-pressure starting direction) are all in the input state. If they are all in the input state normally, the overcurrent starting module in the re-pressure starting direction starts the open protection.

[0041] Among them, the first voltage threshold value and the second voltage threshold value are set according to the critical value of the voltage state in the power supply line when the specific power-consuming equipment is guaranteed to be used normally. The starting mode of the overcurrent starting module in the re-pressure starting direction is particularly suitable for the rapid start of the mother-coupler quick cut when the 35 / 66 / 110KV system shakes due to a short circuit fault in the external power supply line or other power supply line when the generator set is connected to the grid.

[0042] In the present invention, the voltage and frequency anomalies are: if the line voltages between the three phases in the power supply line are greater than the first predetermined voltage setting and the frequency is greater than the predetermined high-frequency setting, or the line voltages between the three phases in the power supply line are less than the second predetermined voltage setting and the frequency is less than the predetermined low-frequency setting, then the voltage and frequency anomalies are.

[0043] In the embodiment of the present invention, in the power supply lines of most enterprises, if the line voltage and frequency between the three phases on the primary side of the main transformer decrease at the same time and are lower than the set value, and the fault voltage decreases slowly and the frequency deviation is large, it means that the power supply capacity is insufficient due to the fault of the remote power grid. For power generation enterprises, when the power grid is disconnected, the voltage and frequency between the three phases may increase and exceed the set value. Therefore, it is necessary to detect two abnormal situations.

[0044] In the present invention, the judgment of whether it is a remote power grid fault or a power generation enterprise disconnecting from the power grid fault includes: judging whether the minimum voltage in the power supply line is greater than a predetermined voltage range, and whether the current value of the power supply line is less than a predetermined current value. If so, it is the remote power grid fault or the power generation enterprise disconnecting from the power grid fault.

[0045] In the embodiment of the present invention, the frequency-voltage startup module includes a frequency-voltage protection, wherein the frequency-voltage protection is used to detect the line voltage U between the three phases of the primary side of the main transformer of the corresponding power supply line in real time. AB , U BC , U CA Are they both greater than the first predetermined voltage value U GY and frequency F m Is it greater than the predetermined high frequency value F? wHqd , or the line voltage U between the three phases on the primary side of the main transformer AB , U BC , U CA Are they all less than the second predetermined voltage value U DY and frequency F m Is it less than the preset low frequency value F? wLqd .

[0046] like Figure 3As shown, when the frequency-voltage protection corresponding to the power supply line I or the power supply line II detects that the line voltage between the three phases of the power supply line I or the power supply line II is greater than the first predetermined voltage setting value and the frequency is greater than the predetermined high-frequency setting value, or the line voltage between the three phases is less than the second predetermined voltage setting value and the frequency is less than the predetermined low-frequency setting value, it indicates that the power supply line I or the power supply line II is abnormal. At the same time, the frequency-voltage starting module detects that the minimum voltage Umin on the primary side of the main transformer in the power supply line I or the power supply line II is greater than the predetermined voltage range and the current value I (a, b, c) on the primary side of the main transformer of the power supply line I or the power supply line II is less than the predetermined current setting value I DL , then cut off (trip) the 35 / 66 / 110kV#1 incoming switch on the corresponding power supply line I or the 35 / 66 / 110kV#2 incoming switch on the power supply line II, and send a power switching signal to the bus fast-cut device to cut off (trip) the corresponding 6 / 10kV#1 incoming switch on the power supply line I or the 6 / 10kV#2 incoming switch on the power supply line II, that is, disconnect (trip) the fault line, and control the 6 / 10kV bus tie switch to close, and supply power through the non-faulty power supply line II or power supply line I. Among them, the minimum voltage range of frequency detection is 10-30V, that is, the predetermined voltage range is 10-30V.

[0047] When the voltage and frequency of the power supply line are abnormal, the accuracy of frequency detection is increased by setting the minimum voltage of the power supply line frequency detection to 10-30V. By setting the maximum starting current setting, the current at startup is less than the preset current setting, which increases the reliability of this starting method and prevents the 6 / 10kV busbar quick-cut device from starting inadvertently.

[0048] When the frequency-voltage starting module is started, it is necessary to detect whether the circuit breaker closing current of the incoming switch and the frequency-voltage protection input pressure plate are both in the input state. If both are normally input, the frequency-voltage starting module starts the open protection.

[0049] Among them, the first predetermined voltage setting, the second predetermined voltage setting, the predetermined high-frequency setting, the predetermined low-frequency setting and the predetermined current setting are set according to the critical values ​​of the voltage, current and frequency states in the power supply line when the specific electrical equipment ensures the minimum normal use.

[0050] In the present invention, the current and frequency anomalies are: if the current value in the power supply line is less than a predetermined no-current set value, and the frequency is less than a predetermined low-frequency set value, then the current and frequency anomalies are.

[0051] In an embodiment of the present invention, when the upper switch of the 35 / 66 / 110KV external power supply line trips, the power supply line is directly without voltage and current. By detecting the current value and frequency on the primary side of the main transformer in the power supply line, it can be determined whether there is an abnormality in the power supply line.

[0052] In the present invention, the low-frequency no-current starting module also includes: when the low-frequency no-current starting module detects that there are current and frequency abnormalities in one of the two power supply lines, it simultaneously determines whether the maximum voltage in the power supply line is less than 90V. If so, it means that the upper switch of the external network power supply line has tripped.

[0053] In the embodiment of the present invention, the low-frequency no-current starting module includes a low-frequency no-current protection, wherein the low-frequency no-current protection is used to detect whether the current value I (a, b, c) on the primary side of the main transformer on the power supply line is less than a predetermined no-current setting value I wl And whether the frequency is less than the predetermined low frequency value F wLqd .

[0054] like Figure 4 As shown, when the low-frequency no-current protection corresponding to the power supply line I or the power supply line II detects that the current value I (a, b, c) of the power supply line I or the power supply line II is less than the preset no-current setting value I wl and frequency F m When it is less than the preset low-frequency set value FwLqd, it indicates that the power supply line I or the power supply line II is abnormal. At the same time, when the low-frequency no-current starting module detects that the maximum voltage value Umax on the primary side of the main transformer of the power supply line I or the power supply line II is less than 90V and the minimum voltage value Umin is greater than 10-30V, the corresponding 35 / 66 / 110kV#1 incoming line switch on the power supply line I or the 35 / 66 / 110kV#2 incoming line switch on the power supply line II is cut off (tripped), and a power switching signal is sent to the busbar fast-cutting device to cut off (trip) the corresponding 6 / 10kV#1 incoming line switch on the power supply line I or the 6 / 10kV#2 incoming line switch on the power supply line II, that is, to disconnect (trip) the faulty line and control the 6 / 10kV busbar switch to close, and supply power through the non-faulty power supply line II or power supply line I or power supply line II.

[0055] When the power supply system is operating normally, the maximum voltage in the power supply line should be greater than 90V, and the minimum voltage value of the power supply line frequency should be accurately detected to be no less than 10-30V; the low-frequency no-current starting module can accurately detect the minimum voltage through the maximum voltage and frequency to determine whether the abnormality is caused by the upper switch of the external power supply line, thereby preventing the 6 / 10kV busbar quick-cutting device from starting up incorrectly.

[0056] When the low-frequency no-current starting module is started, it is necessary to detect whether the low-frequency no-current protection input pressure plates are all in the input state. If they are all normally input, the low-frequency no-current starting module starts the open protection.

[0057] Among them, the predetermined low-frequency constant is set according to the critical value of the frequency state when the specific electrical equipment is in normal use; the predetermined no-current constant is set according to the minimum current when the specific power line is in normal use.

[0058] In the present invention, the voltage abnormality is: if the line voltages between the three phases in the power supply line are all less than the first set value, it is the voltage abnormality.

[0059] In the present invention, the determination of whether it is an external fault of the power supply system includes: determining whether the maximum current value in the power supply line is less than the directional overcurrent closing value, and the direction points to the load side. If so, it is an external fault of the power supply system.

[0060] In the embodiment of the present invention, the directional overcurrent low voltage starting module includes a first low voltage fast switching protection, wherein the first low voltage fast switching protection is used to detect the line voltage U between the three phases of the primary side of the main transformer of the power supply line in real time. AB , U BC , U CA Are they all less than the first set value?

[0061] like Figure 5 As shown, when the first low-voltage fast switching protection corresponding to the power supply line I or the power supply line II detects that the line voltages between the three phases of the power supply line I or the power supply line II are all less than the first set value, it indicates that the power supply line I or the power supply line II is abnormal. At the same time, the directional overcurrent low-voltage starting module detects that the maximum current I (a, b, c) max on the primary side of the main transformer in the power supply line I or the power supply line II is less than the directional overcurrent closing lock value, and the direction points to the load side, then the corresponding 35 / 66 / 110kV#1 incoming line switch on the power supply line I or the 35 / 66 / 110kV#2 incoming line switch on the power supply line II is cut off (tripped), and at the same time, a power switching signal is sent to the bus fast-cut device to cut off (trip) the corresponding 6 / 10kV#1 incoming line switch on the power supply line I or the 6 / 10kV#2 incoming line switch on the power supply line II, that is, disconnect (trip) the fault line, and at the same time control the 6 / 10kV bus switch to close, and supply power through the non-faulty power supply line II or power supply line I.

[0062] When the line voltages between the three phases of the power supply line are simultaneously less than the first set value, if the voltage drop is caused by an external fault in the power supply system, the current direction of the power supply line will change and be less than the directional overcurrent blocking value; the directional overcurrent low-voltage starting module can determine whether it is an external fault of the power supply system based on the line voltages between the three phases and the maximum directional current, thereby preventing the 6 / 10kV busbar quick-cutting device from mistakenly starting when there is an internal fault in the power supply system.

[0063] When the directional overcurrent locking low-voltage starting module is started, it is necessary to detect whether the circuit breaker closing current of the incoming switch and the first low-voltage fast switching protection input pressure plate are both in the input state. If both are normally input, the directional overcurrent low-voltage starting module starts the open protection.

[0064] Among them, the first set value of the predetermined voltage is set according to the specific electrical equipment to ensure that it is greater than the minimum voltage value by a certain margin when in normal use; the predetermined directional overcurrent closing set value is set according to the maximum current of the specific power line when in normal use.

[0065] The directional overcurrent low-voltage starting module is used as a backup starting method for the main bus fast-cutting device when the external network line fails and the power is shaken. It realizes the backup starting method of the above starting method for voltage fluctuations caused by all external network faults, so as to realize rapid identification and judgment and rapid issuance of switching commands without considering the voltage drop caused by the normal starting of a large number of motors. Among them, the value of the first set value is set to 85%UN according to the minimum allowable voltage value.

[0066] In the present invention, it also includes: a non-directional overcurrent low-voltage starting module; the non-directional overcurrent low-voltage starting module is connected to the 6 / 10kV bus coupler quick-cutting device; when the non-directional overcurrent low-voltage starting module detects that the line voltages between the three phases of one of the two power supply lines are all less than the second set value, it is determined whether the voltage drop is not caused by the startup of the electrical equipment. If so, the 6 / 10kV bus coupler quick-cutting device controls the disconnection of the faulty line, and at the same time connects the line between the non-fault line and the electrical equipment corresponding to the faulty line.

[0067] In the present invention, the determination of whether the voltage drop is not caused by the startup of the electrical equipment includes: determining whether the maximum current value in the power supply line is less than the overcurrent shutdown setting value; if so, the voltage drop is not caused by the startup of the electrical equipment.

[0068] In the embodiment of the present invention, the 6 / 10kV busbar quick-cut device is respectively connected to two 6 / 10kV incoming line protection devices, each of which includes a corresponding non-directional overcurrent low-voltage starting module. The two 6 / 10kV incoming line protection devices are respectively connected to their corresponding power supply lines.

[0069] The non-directional overcurrent low voltage starting module includes a second low voltage fast switching protection, wherein the second low voltage fast switching protection is used to detect the line voltage U between the three phases of the secondary side of the main transformer of the power supply line in real time. AB , U BC , U CA Are they all less than the second set value?

[0070] like Figure 6As shown, when the second low-voltage fast switching protection corresponding to the power supply line I or the power supply line II detects that the line voltages between the three phases of the power supply line I or the power supply line II are all less than the second set value, it indicates that the power supply line I or the power supply line II is abnormal. At the same time, the non-directional overcurrent low-voltage starting module detects that the maximum current I (a, b, c) max on the secondary side of the main transformer in the power supply line I or the power supply line II is less than the overcurrent closing value, and then sends a power switching signal to the bus fast-cut device to cut off the corresponding 6 / 10kV#1 incoming line switch on the power supply line I or the 6 / 10kV#2 incoming line switch on the power supply line II, thereby disconnecting the faulty line, and at the same time controlling the 6 / 10kV bus switch to close, and supplying power through the power supply line II.

[0071] When the line voltages between the three phases of the power supply line are simultaneously less than the second set value, if the voltage drop is caused by an internal short circuit fault in the power supply system, the maximum current of the power supply line will be greater than the overcurrent shutdown value; the non-directional overcurrent low-voltage starting module can determine whether the voltage drop is caused by an internal short circuit fault based on the line voltages and maximum current between the three phases, thereby preventing the 6 / 10kV busbar quick-cutting device from starting incorrectly.

[0072] When the non-directional overcurrent low-voltage starting module is started, it is necessary to detect whether the circuit breaker closing current of the incoming switch and the second low-voltage fast switching protection input pressure plate are both in the input state. If both are normally input, the directional overcurrent low-voltage starting module starts the open protection.

[0073] The second set value of the predetermined voltage is set according to the minimum voltage value when the specific power equipment is in normal use; the predetermined non-directional overcurrent blocking value is set according to the maximum current of the motor group of the specific power line. The non-directional overcurrent low-voltage starting module and the directional overcurrent low-voltage starting module form a double low-voltage starting bus fast-cut mode that cooperates with each other, which serves as a backup analog starting mode for the 6 / 10kV bus fast-cut device when the external network fails and the power is shaken. The value of the second set value of the voltage is set to 75%UN according to the minimum allowable voltage value.

[0074] A 100ms delay start module is provided between the re-pressure start directional overcurrent start module, the frequency-voltage start module, the directional overcurrent low-voltage start module and the non-directional overcurrent low-voltage start module and the 6 / 10kV bus coupler quick-cut device. The delay start module is used to reserve time for the start action of each component of the above start module to avoid the main protection action time of the external power grid short-circuit fault. A 20ms delay start module is provided between the low-frequency no-current start module and the 6 / 10kV bus coupler quick-cut device to confirm the change of the switch position from closed to open.

[0075] It can be understood that the above-mentioned various method embodiments mentioned in the present invention can be combined with each other to form a combined embodiment without violating the principle logic. Due to space limitations, the present invention will not go into details.

[0076] The present invention adopts an original multi-protection adaptive analog startup power supply fast switching device, which is composed of multiple startup modules and bus-coupled fast switching devices to realize the judgment of external network power shaking faults, and realize the rapid automatic identification and power switching of the external network voltage drop within 100ms. The modular combination method has strong applicability and powerful user programmable functions. The user's main substation can meet the requirements of automatic and fast power switching by using a set of the present invention's devices, and achieve excellent performance in the enterprise power system's anti-power shaking ability.

[0077] The present invention breaks through the technical bottleneck that the existing busbar quick-cut device only collects analog parameters of one voltage level of the power system, resulting in poor on-site applicability of some analog starting methods, and develops a multi-protection adaptive analog starting power supply quick switching device, which adopts a modular combination method, is flexible and convenient, and has strong applicability. The system is suitable for the enterprise's 35KV, 66KV, 110KV and 6 / 10KV power supply systems, and meets the effective coordination requirements of the enterprise's power supply automatic switching device with generator sets and synchronous motor sets.

[0078] For short-circuit faults of external power supply lines, remote power grid faults, serious short-circuit faults of upper adjacent lines, and upper switch trip faults of external power supply lines, the original combination of four busbar quick-cut starting logics, namely, the re-pressure starting direction overcurrent starting module, the frequency-voltage starting module, the low-frequency no-current starting module, and the direction overcurrent low-voltage starting module, can meet the effective coordination requirements of generator sets and synchronous units, and realize the quick and automatic identification of the external network voltage drop caused by all external network faults within 100ms and send a start command to the 6 / 10KV busbar quick-cut device. After receiving the start signal, the quick-cut device quickly trips the faulty incoming line switch and closes the busbar switch, realizing the disturbance-free rapid switching of the power supply without affecting the normal operation of electrical equipment such as motors, and truly improving the ability to resist external network voltage drops. The non-directional overcurrent low-voltage starting module collects the user's 6 / 10kV side voltage analog parameters, and cooperates with the directional overcurrent locking low-voltage starting mode as a backup analog starting mode when the external network fails and shakes the power. When the above four starting methods are not effectively started, the starting method implements the starting switching command to the 6 / 10KV busbar quick-cut device in 100ms, quickly trips the faulty incoming line switch, closes the busbar switch, and realizes the disturbance-free quick switching of the power supply. The invention can increase the fault accuracy recognition rate to 100%, increase the synchronous switching probability of the busbar quick-cut device to more than 80%, improve the safety of production operation by 100%, and reduce the labor intensity by 80%.

[0079] During the experimental application of the present invention, two short-circuit faults occurred in the adjacent lines of the enterprise's 66kV1# line external network. The overcurrent start module of the re-pressure start direction set by the 66kV1# line protection of the main transformer issued a start-up fast-cut command after 98ms, and the two sets of 6kV busbar fast-cut devices of the main transformer realized the disturbance-free fast switching of the 6kV system power supply in 75ms and 72ms respectively. In the "420" and "830" external network power shaking accidents, the precedent of disturbance-free fast switching of the busbar fast-cut device was opened in the event of an accident. No machine pump stopped, and the production equipment was not affected in any way.

[0080] The present invention is applicable to all power-consuming enterprises with high requirements on power supply reliability, and is particularly applicable to refining and chemical enterprises. The achievement has certain prospects for promotion and application in group refining and chemical enterprises or other domestic refining and chemical enterprises.

[0081] The present invention was applied in Harbin Petrochemical Company on December 25, 2021. After nine external network shaking and power failures, all of them achieved a precedent of rapid switching without disturbance, without downtime, and without impact during accidents. The loss caused by a temporary voltage drop was calculated to be 5 million yuan. There were only five external network shaking in 2022 and two external network shaking failures in 2023, which avoided economic losses of 35 million yuan. The application of the present invention has enabled the company to surpass the group goal of "power shaking does not stop the device" and achieve the ideal ultimate goal of "power shaking does not affect the device"! The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A multi-protection adaptive analog starting power supply fast switching system, characterized in that: include: 6 / 10kV busbar quick-cut device; The 6 / 10kV busbar quick-cut device is respectively connected to the re-voltage starting direction overcurrent starting module, the frequency-voltage starting module, the low-frequency no-current starting module, the direction overcurrent low-voltage starting module and the power supply line; When the overcurrent starting module in the re-pressure starting direction detects that one of the two power supply lines has reverse power, it determines whether the power shake is caused by a short circuit fault of the external network or the upper adjacent line. If so, the power supply line is a faulty line; When the frequency-voltage startup module detects that one of the two power supply lines has abnormal voltage and frequency, it determines whether it is a remote power grid fault or a power generation enterprise disconnection fault from the power grid. If so, the power supply line is a faulty line; When the low-frequency no-current starting module detects that the current and frequency of one of the two power supply lines are abnormal, it is determined that the upper switch of the external power supply line is tripped, and the power supply line is a faulty line; When the directional overcurrent low voltage starting module detects that there is a voltage abnormality in one of the two power supply lines, it is determined whether it is an external fault of the power supply system. If so, the power supply line is a faulty line; The 6 / 10kV busbar quick-cut device starts controlling to disconnect the faulty line, and at the same time connects the line between the non-faulty line and the electrical equipment corresponding to the faulty line.

2. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The step of judging whether the power fluctuation is caused by a short circuit fault in an external network or an upper adjacent line includes: Determine whether one of the line voltages between the three phases in the power supply line is less than the first voltage threshold value, or whether the negative sequence voltage in the power supply line is greater than the second voltage threshold value. If so, when reverse power occurs in the power supply line, it is a power shake caused by a short circuit fault in the external network or the upper adjacent line.

3. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The voltage and frequency anomalies are: If the line voltages between the three phases in the power supply line are greater than the first predetermined voltage setting and the frequency is greater than the predetermined high frequency setting, or the line voltages between the three phases in the power supply line are less than the second predetermined voltage setting and the frequency is less than the predetermined low frequency setting, then the voltage and frequency are abnormal.

4. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The determination of whether it is a remote power grid fault or a power generation enterprise disconnection fault from the power grid includes: It is determined whether the minimum voltage in the power supply line is greater than a predetermined voltage range, and whether the current value of the power supply line is less than a predetermined current value. If so, it is a remote power grid fault or a power generation enterprise disconnection fault from the power grid.

5. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The current and frequency anomalies are: If the current value in the power supply line is less than a predetermined no-current set value, and the frequency is less than a predetermined low-frequency set value, the current and frequency are abnormal.

6. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The low-frequency no-current starting module further includes: When the low-frequency no-current starting module detects that there is current and frequency abnormality in one of the two power supply lines, it simultaneously determines whether the maximum voltage in the power supply line is less than 90V. If so, it means that the upper switch of the external network power supply line has tripped.

7. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The voltage anomaly is: If the line voltages between the three phases in the power supply line are all less than the set values, it is the voltage abnormality.

8. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 1 is characterized in that: The determining whether the fault is external to the power supply system includes: Determine whether the maximum current value in the power supply line is less than the directional overcurrent blocking value, and the direction is pointing to the load side. If so, it is an external fault of the power supply system.

9. The multi-protection adaptive analog starting power supply fast switching system according to any one of claims 1 to 8, characterized in that: Also includes: Non-directional overcurrent low voltage starting module; The non-directional overcurrent low-voltage starting module is connected to the 6 / 10kV bus fast-cut device; When the non-directional overcurrent low-voltage starting module detects that the line voltages between the three phases of one of the two power supply lines are all lower than the set value, it determines whether the voltage drop is not caused by the startup of the electrical equipment. If so, the 6 / 10kV busbar quick-cutting device controls the disconnection of the faulty line, and at the same time connects the line between the non-fault line and the electrical equipment corresponding to the faulty line.

10. The multi-protection adaptive analog quantity starting power supply fast switching system according to claim 9, characterized in that: The determining whether the voltage drop is not caused by the startup of the electrical equipment includes: Determine whether the maximum current value in the power supply line is less than the overcurrent shutdown setting value. If so, the voltage drop is not caused by the startup of the electrical equipment.

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