Method and device for capacitor maintenance, and method and device for transformer voltage regulation early warning

Abstract

The embodiment of the present invention discloses a method and device for capacitor maintenance, and a method and device for early warning of transformer voltage regulation. The capacitor maintenance judgment method includes: obtaining the transformation ratio, bus voltage and comprehensive impedance, and predicted maximum load of the 110kV transformer; obtaining the rated capacity of the remaining capacitor groups excluding the capacitor groups for maintenance work; calculating the minimum voltage of the 10kV bus according to the transformation ratio of the transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor groups; if the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus, it is determined that the capacitor maintenance work is not allowed to start; otherwise, it is determined that the capacitor maintenance work is allowed to start. The technical solution of the embodiment of the present invention obtains relevant data, calculates the minimum voltage of the 10kV bus and the lowest gear of the main transformer, and achieves the effect of ensuring that the 10kV bus voltage is within the qualified range based on a scientific calculation method.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power grid technology, and in particular to a capacitor maintenance method and device, and a transformer voltage regulation early warning method and device. Background Art

[0002] At present, the integration of power grid control is constantly advancing. Controllers have to take on the responsibilities of dispatching, monitoring and controlling at the same time. Among them, voltage regulation, especially 10kV bus voltage regulation, is an important task in the daily work of controllers. Specifically, the voltage regulation of 10kV bus can be achieved by switching capacitors and regulating the voltage of 10kV bus.

[0003] Among them, the 10kV bus voltage regulation depends on the switching of capacitors on the 10kV bus and the on-load regulation of the 110kV main transformer gear. When the 10kV bus voltage is adjusted by frequently switching on and off 10kV capacitors, maintenance is often required. In the prior art, the controller often judges whether maintenance is allowed based on daily work experience. There is no scientific calculation support, and it is likely to make wrong judgments. In addition, in order to prevent the frequent adjustment of the switching of 10kV capacitors, there are also defects in the use of the automatic voltage reactive control (AVC) of the power grid to adjust the grid voltage, which makes it impossible for the 110kV transformer to adjust the voltage when the load peak comes.

[0004] Based on this, grid controllers rely on daily work experience to adjust the 10kV bus voltage without scientific calculation support. Therefore, how to more scientifically ensure that the 10kV bus voltage reaches the qualified voltage has become an urgent problem to be solved in the industry. Summary of the invention

[0005] The embodiments of the present invention provide a capacitor maintenance method and device, and a transformer voltage regulation early warning method and device, so as to ensure that the 10kV bus voltage can be regulated within a qualified range when the load peak arrives.

[0006] In a first aspect, an embodiment of the present invention provides a method for determining whether to allow capacitor maintenance work to start, the determination method comprising:

[0007] Obtain the transformation ratio of the 110kV transformer, the 110kV bus voltage and comprehensive impedance, and predict the maximum load;

[0008] Obtain the rated capacity of the remaining capacitor banks on the 10kV bus bar, excluding the capacitor banks that are undergoing maintenance work;

[0009] Calculate the minimum voltage of the 10kV bus based on the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor banks;

[0010] If the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus, it is determined that the capacitor maintenance work is not allowed to start; otherwise, it is determined that the capacitor maintenance work is allowed to start.

[0011] Optionally, the method for calculating the minimum voltage of the 10kV bus includes:

[0012] According to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the remaining capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the minimum voltage of the 10kV bus.

[0013] Alternatively, the equation for the turns ratio of a 110 kV transformer is as follows:

[0014]

[0015] Where U n is 110kV bus voltage, Pmax is the predicted maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, U min is the minimum voltage of 110kV busbar, n max It is the highest gear of 110kV transformer.

[0016] Optionally, a method for obtaining the transformation ratio of a 110 kV transformer includes:

[0017] Calculate the transformation ratio according to the adjustment gear of the 110kV transformer;

[0018] And / or, the method for obtaining the comprehensive impedance of the 110kV bus includes:

[0019] The comprehensive impedance is calculated based on the line impedance of the 110kV bus and the impedance of the 110kV transformer.

[0020] In a second aspect, an embodiment of the present invention further provides a device for determining whether to allow capacitor maintenance work to start, the device comprising:

[0021] The first data acquisition module is used to obtain the transformation ratio of the 110kV transformer, the 110kV bus voltage and comprehensive impedance, and predict the maximum load;

[0022] The second data acquisition module is used to obtain the rated capacity of the remaining capacitor groups on the 10kV bus bar except for the capacitor groups that are transferred for maintenance work;

[0023] The minimum voltage calculation module is used to calculate the minimum voltage of the 10kV bus according to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor bank;

[0024] The judgment module is used to determine that if the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus, then the capacitor maintenance work is not allowed to start; otherwise, it is determined that the capacitor maintenance work is allowed to start.

[0025] In a third aspect, an embodiment of the present invention further provides a voltage regulation early warning method for a 110 kV transformer, the early warning method comprising:

[0026] Obtain 110kV bus voltage and comprehensive impedance, predict maximum load and rated capacity of capacitor bank;

[0027] Calculate the lowest gear of the 110kV transformer based on the 110kV bus voltage, comprehensive impedance, predicted maximum load, and rated capacity of the capacitor bank;

[0028] If the current gear of the 110kV transformer is lower than the lowest gear, the warning should raise the gear of the 110kV transformer to a level higher than the lowest gear.

[0029] Optionally, the method for calculating the lowest gear of the 110kV transformer includes:

[0030] According to the lowest gear of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the lowest gear of the 110kV transformer.

[0031] Alternatively, the equation for the turns ratio of a 110 kV transformer is as follows:

[0032]

[0033] Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, n min It is the lowest gear of 110kV transformer.

[0034] Optionally, the method for obtaining the comprehensive impedance of the 110kV bus includes:

[0035] The comprehensive impedance is calculated based on the line impedance of the 110kV bus and the impedance of the 110kV transformer.

[0036] In a fourth aspect, an embodiment of the present invention further provides a voltage regulation warning device for a 110 kV transformer, the device comprising:

[0037] The third data acquisition module is used to obtain the 110kV bus voltage and comprehensive impedance, predict the maximum load and the rated capacity of the capacitor bank;

[0038] The lowest gear calculation module is used to calculate the lowest gear of the 110kV transformer according to the 110kV bus voltage, comprehensive impedance, predicted maximum load, and rated capacity of the capacitor bank;

[0039] The early warning module is used to warn that if the current gear of the 110kV transformer is lower than the lowest gear, the gear of the 110kV transformer should be raised and higher than the lowest gear.

[0040] The technical solution of the embodiment of the present invention obtains the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance and the predicted maximum load, and the rated capacity of the remaining capacitor groups on the 10kV bus except the capacitor groups transferred for maintenance work, calculates the minimum voltage of the 10kV bus according to the obtained data, and compares it with the minimum value of the qualified range of the 10kV bus, and determines whether to allow the capacitor maintenance work to start based on the comparison result, thereby solving the problem that the controller judges whether the remaining capacitor groups can ensure that the 10kV bus voltage remains within the qualified range when the load peak arrives after the capacitor group is transferred for maintenance based on daily work experience, but there is no scientific calculation basis. Compared with the prior art, the embodiment of the present invention provides a scientific basis for ensuring that the 10kV bus voltage is within the qualified range, and achieves the effect of ensuring that the 10kV bus voltage is within the qualified range when the load peak arrives. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flow chart of a method for determining whether to allow capacitor maintenance work to start, provided by an embodiment of the present invention;

[0042] Figure 2 is a flow chart of another method for determining whether to allow capacitor maintenance work to start provided by an embodiment of the present invention;

[0043] Figure 3 is a schematic diagram of an impedance relationship provided by an embodiment of the present invention;

[0044] Figure 4 It is a structural diagram of a device for judging whether to allow capacitor maintenance work to start, provided by an embodiment of the present invention;

[0045] Figure 5 This is a flow chart of a voltage regulation early warning method for a 110kV transformer provided by an embodiment of the present invention;

[0046] Figure 6 It is a flow chart of another 110kV transformer voltage regulation early warning method provided by an embodiment of the present invention;

[0047] Figure 7 It is a structural diagram of a voltage regulation warning device for a 110kV transformer provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0049] As described in the background technology, the 10kV bus voltage is regulated by 10kV capacitors, which requires frequent switching of 10kV capacitors. Therefore, 10kV capacitors often need to be switched for maintenance, and sometimes they even need to be repaired on the same day. When the operator applies to the controller for the 10kV capacitor group to be switched for maintenance, the controller often judges whether the voltage can be adjusted to meet the 10kV bus voltage when the load peak comes based on daily operating experience, without scientific calculation support. It is very likely that an erroneous judgment will occur, resulting in the 10kV bus voltage exceeding the lower limit at the load peak and a lack of voltage regulation means.

[0050] Based on the above technical problems, this embodiment proposes the following solutions:

[0051] An embodiment of the present invention provides a method for determining whether to allow capacitor maintenance work to start. Figure 1 A flowchart of a method for determining whether to allow capacitor maintenance work to start is provided in an embodiment of the present invention. This embodiment can be applied to determine whether to allow capacitor maintenance work to start when the peak load of the power grid comes, so as to ensure that the 10kV bus voltage can be adjusted to a qualified range. The method can be executed by a device for determining whether to allow capacitor maintenance work to start, and the device can be implemented by software and / or hardware. The method for determining whether to allow capacitor maintenance work to start specifically includes the following steps:

[0052] S110, obtain the transformation ratio of the 110kV transformer, the 110kV bus voltage and the comprehensive impedance, and predict the maximum load.

[0053] Specifically, the transformation ratio of the 110kV transformer, that is, the voltage or current ratio between the primary winding and the secondary winding of the 110kV transformer, can be adjusted by adjusting the gear of the 110kV transformer. The transformation ratio of the 110kV transformer can be obtained by obtaining the gear of the 110kV transformer.

[0054] The 110kV bus voltage is directly connected to the large power grid. Under normal circumstances, the voltage does not change much and is basically constant near a voltage value in a short period of time. When applied to this judgment method, it can be considered to be a constant value in a short period of time. However, the 110kV bus voltage has different values ​​in different time periods. When judging whether to allow the capacitor maintenance work to start, the real-time 110kV bus voltage value is selected for calculation.

[0055] The predicted maximum load is a predicted value of the maximum power required to be consumed by the maximum load before the load peak arrives. Specifically, the predicted maximum load is determined according to the operation of the power grid. For example, the predicted maximum load changes before the daily load peak arrives.

[0056] S120. Obtain the rated capacity of the remaining capacitor groups on the 10 kV bus bar, excluding the capacitor groups that are undergoing maintenance work.

[0057] Specifically, after obtaining the rated capacity of the remaining capacitor groups on the 10kV bus that can be used for voltage regulation when the load peak arrives, it can be determined whether the remaining capacitor groups can meet the requirements of regulating the 10kV bus voltage to within the acceptable range when all the capacitor groups applying for maintenance are overhauled.

[0058] S130. Calculate the minimum voltage of the 10kV bus based on the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor banks.

[0059] Specifically, based on the acquired data such as the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load and the rated capacity of the remaining capacitor banks, an equation is established based on the transformation ratio of the 110kV transformer, thereby calculating the minimum voltage of the 10kV bus when the transformation ratio of the 110kV transformer is the largest.

[0060] S140. If the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus, it is determined that the capacitor maintenance work is not allowed to start; otherwise, it is determined that the capacitor maintenance work is allowed to start.

[0061] Exemplarily, the qualified range of 10kV bus voltage is 10.0-10.7kV. By setting the transformation ratio of 110kV transformer to the maximum, the minimum voltage of 10kV bus is calculated, and the minimum voltage of 10kV bus is compared with the minimum value of the qualified range of 10kV bus voltage to determine whether to allow the capacitor maintenance work to start. If the minimum voltage of the 10kV bus is less than the minimum value of the qualified range of the 10kV bus voltage, it means that when all the capacitor groups that apply for transfer maintenance work are overhauled, the remaining capacitor groups cannot adjust the 10kV bus voltage to the minimum value of the qualified range when the load peak arrives, resulting in the 10kV bus voltage exceeding the lower limit. Therefore, it is determined that the capacitor maintenance work is not allowed to start; if the minimum voltage of the 10kV bus is greater than or equal to the minimum value of the qualified range of the 10kV bus voltage, it means that when all the capacitor groups that apply for transfer maintenance work are overhauled, the remaining capacitor groups can adjust the 10kV bus voltage to the qualified range when the load peak arrives. Therefore, it is determined that the capacitor maintenance work is allowed to start.

[0062] The technical solution of this embodiment obtains the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance and the predicted maximum load, and the rated capacity of the remaining capacitor groups on the 10kV bus except the capacitor groups transferred for maintenance work, calculates the minimum voltage of the 10kV bus according to the obtained data, and compares it with the minimum value of the qualified range of the 10kV bus, and determines whether to allow the capacitor maintenance work to start based on the comparison result, which solves the problem that the controller judges whether the remaining capacitor groups can ensure that the 10kV bus voltage remains within the qualified range when the load peak comes after the capacitor group is transferred for maintenance based on daily work experience, but there is no scientific calculation basis. Compared with the prior art, the embodiment of the present invention provides a scientific basis for ensuring that the 10kV bus voltage is within the qualified range, and achieves the effect of ensuring that the 10kV bus voltage is within the qualified range when the load peak comes.

[0063] Optional, Figure 2 FIG. 1 is a flowchart of another method for determining whether to allow capacitor maintenance work to start provided by an embodiment of the present invention. Figure 2 , the methods for judging whether to allow capacitor maintenance work to start include:

[0064] S210, obtain the transformation ratio of the 110kV transformer, the 110kV bus voltage and the comprehensive impedance, and predict the maximum load.

[0065] in, Figure 3 is a schematic diagram of an impedance relationship provided by an embodiment of the present invention. Figure 3In the process of transmitting electric energy from the 110kV bus 10 to the 10kV bus, the comprehensive impedance Z0 can be obtained by the line impedance Z1 on the 110kV bus line 30 and the impedance Z of the 110kV transformer 40. T By adding the calculated values, the line impedance Z1 on the 110 kV bus line 30 is equal to R1 + X1, and the impedance Z of the 110 kV transformer 40 is equal to T =R T +X T , that is, Z0=Z1+Z T =(R1+X1)+(R T +X T )=(R1+R T )+(X1+X T ), let R0=R1+R T , X0=X1+X T , then Z0=R0+X0, and each impedance value is fixed. Predicted maximum load S max The maximum active power P can be predicted max and predicted maximum reactive power Q max Calculated by adding.

[0066] S220. Obtain the rated capacity of the remaining capacitor groups on the 10 kV bus bar, excluding the capacitor groups that are undergoing maintenance work.

[0067] S230. According to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the remaining capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the minimum voltage of the 10kV bus.

[0068] Specifically, according to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance and the rated capacity of the remaining capacitor bank, an equation for the transformation ratio of the 110kV transformer can be established, so that the single unknown quantity of the minimum voltage of the 10kV bus can be calculated. The transformation ratio equation of the 110kV transformer is as follows:

[0069]

[0070] Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, U min is the minimum voltage of 110kV busbar, n max It is the highest gear of 110kV transformer.

[0071] Among them, the 110kV bus voltage U n It changes in different time periods, and a stable value in a shorter time period can be selected for calculation.

[0072] The right side of the equation for the transformation ratio of the 110kV transformer is the calculation formula for the transformation ratio k. From the calculation formula, it can be seen that the transformation ratio of the 110kV transformer can be calculated using the adjustment gear n of the 110kV transformer to obtain the transformation ratio of the 110kV transformer. Specifically, in this embodiment, by setting the gear of the 110kV transformer to the highest gear n max , that is, when the transformation ratio of the 110kV transformer is the largest, the minimum voltage U of the 110kV busbar is calculated. min , if the minimum voltage U min If the minimum voltage U min If it is less than the minimum value of the qualified range of 10kV bus voltage, the remaining capacitor groups cannot ensure that the 10kV bus voltage is within the qualified range, and capacitor maintenance work is not allowed to start.

[0073] S240. If the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus, it is determined that the capacitor maintenance work is not allowed to start; otherwise, it is determined that the capacitor maintenance work is allowed to start.

[0074] It can be seen from S210-S240 that the minimum voltage of the 10kV bus can be calculated through the equation of the transformation ratio of the 110kV transformer, and the judgment on whether to start the capacitor maintenance work is made based on this. Compared with the prior art, the embodiment of the present invention uses a more scientific method to ensure that the 10kV bus voltage is within the qualified range when the load peak comes.

[0075] For example, the highest gear n of a 110 kV transformer max The 17th gear, there are two groups of capacitors on the 10kV bus, each with a rated capacity of 4.2Mvar. The operator applies to transfer one group of capacitors for maintenance. The current 110kV bus voltage U n The bus voltage is 115kV. The bus load at the peak load at noon is 46.4MW+10.6Mvar. The comprehensive impedance Z0=20+j100Ω. Based on the above data, the minimum voltage U of the bus at the peak load at noon can be calculated. min It is 10.9kV, which is much higher than the lower limit of the qualified range of 10kV bus voltage, so the maintenance work of the 10kV capacitor applied by the operating personnel can be allowed to start.

[0076] The embodiment of the present invention also provides a device for determining whether to allow capacitor maintenance work to start. Figure 41 is a structural diagram of a device for determining whether to allow capacitor maintenance work to start, provided by an embodiment of the present invention. The device 100 for determining whether to allow capacitor maintenance work to start includes:

[0077] The first data acquisition module 101 is used to obtain the transformation ratio of the 110 kV transformer, the 110 kV bus voltage and the comprehensive impedance, and predict the maximum load.

[0078] The second data acquisition module 102 is used to obtain the rated capacity of the remaining capacitor groups on the 10 kV bus bar except the capacitor groups that are in maintenance work.

[0079] The minimum voltage calculation module 103 is used to calculate the minimum voltage of the 10kV bus according to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor banks.

[0080] The judgment module 104 is used to determine that the capacitor maintenance work is not allowed to start if the lowest voltage is lower than the lowest value of the qualified range of the 10kV bus; otherwise, it is determined that the capacitor maintenance work is allowed to start.

[0081] The device 100 for determining whether to allow capacitor maintenance work to start provided in this embodiment is used to execute the method for determining whether to allow capacitor maintenance work to start provided in the embodiment of the present invention, and has functional modules and beneficial effects corresponding to the execution method.

[0082] As described in the background technology, the current power grid uses AVC technology for voltage regulation, which can ensure power quality, improve transmission efficiency and reduce network losses, but due to algorithm and other reasons, AVC technology still has some defects. When the load peak comes, usually all 10kV capacitor banks have been put into operation, and although the 110kV transformer gear has not reached the upper limit of the operating gear, the on-load voltage regulation will be locked due to the heavy or full load operation of the 110kV transformer, resulting in the 10kV bus voltage exceeding the lower limit and unable to regulate the voltage.

[0083] Based on the above technical problems, this embodiment proposes the following solutions:

[0084] The embodiment of the present invention also provides a voltage regulation early warning method for a 110kV transformer. Figure 5 This is a flow chart of a 110kV transformer voltage regulation warning method provided by an embodiment of the present invention. Figure 5 , the voltage regulation warning method of the 110kV transformer includes:

[0085] S310, obtain 110kV bus voltage and comprehensive impedance, predict maximum load and rated capacity of capacitor bank.

[0086] Specifically, the 110 kV bus voltage and comprehensive impedance and the predicted maximum load have been explained in the above embodiment and will not be described in detail here. The rated capacity of the capacitor bank is the maximum power that the capacitor can output. The data of the 110 kV bus voltage and comprehensive impedance, the predicted maximum load and the rated capacity of the capacitor bank are obtained for subsequent calculation.

[0087] S320. Calculate the lowest gear of the 110kV transformer based on the 110kV bus voltage, comprehensive impedance, predicted maximum load, and rated capacity of the capacitor bank.

[0088] Specifically, based on the acquired data such as 110kV bus voltage, comprehensive impedance, predicted maximum load and rated capacity of the capacitor bank, an equation is established based on the transformation ratio of the 110kV transformer, so as to calculate the lowest gear that the 110kV transformer needs to adjust when the lower limit of the qualified range of the 10kV bus voltage is reached, 10.0kV, to ensure that the 10kV bus voltage can be within the qualified range when the load peak arrives.

[0089] S330. If the current gear of the 110kV transformer is lower than the lowest gear, the warning should raise the gear of the 110kV transformer to a level higher than the lowest gear.

[0090] Specifically, when the 10kV bus voltage is calculated to be the lowest value of the qualified range, the 110kV transformer should be adjusted to the lowest gear, and then the current gear of the 110kV transformer is compared with the lowest gear. If the current gear of the 110kV transformer is lower than the lowest gear, it means that the current transformation ratio of the 110kV transformer cannot meet the requirements of adjusting the 10kV bus voltage to the qualified range. At this time, the gear of the 110kV transformer should be adjusted to a gear higher than the calculated lowest gear to ensure that the 10kV bus voltage can be adjusted to the qualified range when the load peak comes.

[0091] The technical solution of this embodiment, by obtaining data such as 110kV bus voltage and comprehensive impedance, predicted maximum load and rated capacity of capacitor bank, calculates according to the obtained data that when the load peak comes, the 10kV bus voltage is adjusted to the lower limit of the qualified range, and the gear of the 110kV transformer needs to be adjusted to the lowest gear, and compared with the current gear of the 110kV transformer, and the gear of the 110kV transformer is adjusted according to the comparison result, which solves the problem that when the load peak comes, the on-load voltage regulation is locked due to the heavy load or full load operation of the 110kV transformer, and the 110kV transformer cannot be regulated although it has not reached the upper limit of the operating gear, resulting in the 10kV bus voltage exceeding the lower limit. Compared with the prior art, this embodiment provides a method for early warning of the gear adjustment of the 110kV transformer, which achieves the effect of ensuring that the 10kV bus voltage is within the qualified range when the load peak comes.

[0092] Optional, Figure 6 FIG. 1 is a flow chart of another 110kV transformer voltage regulation warning method provided by an embodiment of the present invention. Figure 6 , the voltage regulation warning method includes:

[0093] S410, obtain 110kV bus voltage and comprehensive impedance, predict maximum load and rated capacity of capacitor bank.

[0094] Also see Figure 3 The method of obtaining the comprehensive impedance of the 110kV bus is similar to the above-mentioned embodiments and will not be repeated here.

[0095] S420. According to the lowest gear of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the lowest gear of the 110kV transformer.

[0096] Specifically, according to the lowest gear of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance and the rated capacity of the capacitor bank, an equation for the transformation ratio of the 110kV transformer can be established to calculate the single unknown quantity of the lowest gear of the 110kV transformer. The equation for the transformation ratio of the 110kV transformer is as follows:

[0097]

[0098] Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, n min It is the lowest gear of 110kV transformer.

[0099] Among them, the lowest value of 10kV bus voltage 10.0kV is selected for calculation, and the 110kV bus voltage U n Select a stable value within a short period of time for calculation. Predict the maximum active power P max and predicted maximum reactive power Q max It can be determined based on the operation status of the power grid.

[0100] From the transformation ratio equation of the 110kV transformer, it can be known that the lowest gear that the 110kV transformer needs to be adjusted to can be calculated using the lowest value of the 10kV bus voltage, 10.0kV. If the current gear of the 110kV transformer is lower than the lowest gear, it is necessary to warn before the load peak arrives to raise the gear to a gear higher than the lowest gear; if the current gear of the 110kV transformer is higher than the lowest gear, it means that at the load peak, the current gear of the 110kV transformer can ensure that the 10kV bus voltage is adjusted to within the acceptable range. Therefore, there is no need to warn of raising the voltage, and the gear can be lowered to keep the 10kV bus voltage within the acceptable range.

[0101] S430. If the current gear of the 110kV transformer is lower than the lowest gear, the warning should raise the gear of the 110kV transformer to a level higher than the lowest gear.

[0102] It can be seen from S410-S430 that the lowest gear that the 110kV transformer should be adjusted to at least can be calculated through the equation of the transformation ratio of the 110kV transformer, and it is judged whether to increase the gear of the 110kV transformer in advance. Compared with the prior art, the embodiment of the present invention provides a method for pre-judgment and warning voltage regulation, which can ensure that the 10kV bus voltage is within the qualified range when the load peak comes.

[0103] For example, the highest gear n of a 110 kV transformer max There are 17 gears, and the current gear n is 6 gears; there are two groups of capacitors on the 10kV bus, with a rated capacity of c×Q c is 2×4.2Mvar, the current 110kV bus voltage U n The 10kV bus load at the peak load time at noon is 46.4MW+10.6Mvar, and the comprehensive impedance Z0=20+j100Ω. Based on the above data, the lowest gear n that the 110kV transformer should be set can be calculated. min The value is 7.8, and the integer is 8, which means that when the load peak comes, the 110kV transformer's gear position should be set to 8 to ensure that the 10kV bus voltage is within the qualified range. At this time, the current gear position n of the 110kV transformer is 6, so it is necessary to raise the gear position of the 110kV transformer to 8 gears higher than the lowest gear position.

[0104] The embodiment of the present invention also provides a voltage regulation early warning device for a 110kV transformer. Figure 7 This is a structural diagram of a voltage regulation warning device for a 110kV transformer provided by an embodiment of the present invention, see Figure 7 , the voltage regulation warning device 200 of the 110kV transformer includes:

[0105] The third data acquisition module 201 is used to obtain the 110 kV bus voltage and comprehensive impedance, the predicted maximum load and the rated capacity of the capacitor bank.

[0106] The lowest gear calculation module 202 is used to calculate the lowest gear of the 110kV transformer according to the 110kV bus voltage, comprehensive impedance, predicted maximum load, and rated capacity of the capacitor bank.

[0107] The early warning module 203 is used to warn that if the current gear of the 110kV transformer is lower than the lowest gear, the gear of the 110kV transformer should be raised and higher than the lowest gear.

[0108] The 110kV transformer voltage regulation warning device 200 provided in this embodiment is used to execute the 110kV transformer voltage regulation warning method provided in the embodiment of the present invention, and has corresponding functional modules and beneficial effects of the execution method.

[0109] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for determining whether to allow capacitor maintenance work to start, characterized in that: include: Obtain the transformation ratio of the 110kV transformer, the 110kV bus voltage and comprehensive impedance, and predict the maximum load; Obtain the rated capacity of the remaining capacitor banks on the 10kV bus bar, excluding the capacitor banks that are undergoing maintenance work; Calculate the minimum voltage of the 10kV bus according to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor bank; If the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus, it is determined that the capacitor maintenance work is not allowed to start; Otherwise, it is determined that the capacitor maintenance work is allowed to start; Wherein, the method for calculating the minimum voltage of the 10kV bus includes: According to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the remaining capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the minimum voltage of the 10kV bus; The equation for the transformation ratio of the 110 kV transformer is as follows: Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, U min is the minimum voltage of 10kV busbar, n max It is the highest gear of 110kV transformer; Among them, n max The value includes 17.

2. The method for determining whether to allow capacitor maintenance work to start according to claim 1, characterized in that: The method for obtaining the transformation ratio of the 110kV transformer includes: Calculating the transformation ratio according to the adjustment gear of the 110kV transformer; And / or, the method for obtaining the comprehensive impedance of the 110kV bus includes: The comprehensive impedance is calculated based on the line impedance of the 110 kV bus and the impedance of the 110 kV transformer.

3. A device for determining whether to allow capacitor maintenance work to start, characterized in that: include: The first data acquisition module is used to obtain the transformation ratio of the 110kV transformer, the 110kV bus voltage and comprehensive impedance, and predict the maximum load; The second data acquisition module is used to obtain the rated capacity of the remaining capacitor groups on the 10kV bus bar except for the capacitor groups that are transferred for maintenance work; A minimum voltage calculation module, used for calculating the minimum voltage of the 10kV bus according to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the remaining capacitor bank; A judgment module, used for judging that the capacitor maintenance work is not allowed to start if the minimum voltage is lower than the minimum value of the qualified range of the 10kV bus; Otherwise, it is determined that the capacitor maintenance work is allowed to start; Wherein, the method for calculating the minimum voltage of the 10kV bus includes: According to the transformation ratio of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the remaining capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the minimum voltage of the 10kV bus; The equation for the transformation ratio of the 110 kV transformer is as follows: Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, U min is the minimum voltage of 10kV busbar, n max It is the highest gear of 110kV transformer; Among them, n max The value of includes 17.

4. A voltage regulation early warning method for a 110kV transformer, characterized in that: include: Obtain 110kV bus voltage and comprehensive impedance, predict maximum load and rated capacity of capacitor bank; Calculate the lowest gear of the 110kV transformer according to the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the capacitor bank; If the current gear of the 110kV transformer is lower than the minimum gear, the warning should increase the gear of the 110kV transformer to a level higher than the minimum gear; Wherein, the method for calculating the lowest gear of the 110kV transformer includes: According to the lowest gear of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the lowest gear of the 110kV transformer; The equation for the transformation ratio of the 110 kV transformer is as follows: Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, n min It is the lowest gear of 110kV transformer.

5. The voltage regulation early warning method of the 110kV transformer according to claim 4 is characterized in that: The method for obtaining the comprehensive impedance of the 110kV bus includes: The comprehensive impedance is calculated based on the line impedance of the 110 kV bus and the impedance of the 110 kV transformer.

6. A voltage regulation warning device for a 110kV transformer, characterized in that: include: The third data acquisition module is used to obtain the 110kV bus voltage and comprehensive impedance, predict the maximum load and the rated capacity of the capacitor bank; A lowest gear calculation module, used for calculating the lowest gear of the 110kV transformer according to the 110kV bus voltage, the comprehensive impedance, the predicted maximum load, and the rated capacity of the capacitor bank; An early warning module, used for warning that if the current gear of the 110kV transformer is lower than the minimum gear, the gear of the 110kV transformer should be raised and higher than the minimum gear; Wherein, the method for calculating the lowest gear of the 110kV transformer includes: According to the lowest gear of the 110kV transformer, the 110kV bus voltage, the comprehensive impedance, and the rated capacity of the capacitor bank, an equation for the transformation ratio of the 110kV transformer is established; wherein the unknown quantity included in the equation is the lowest gear of the 110kV transformer; The equation for the transformation ratio of the 110 kV transformer is as follows: Where U n is 110kV bus voltage, P max To predict the maximum active power, R0 is the comprehensive resistance, Q max To predict the maximum reactive power, c×Q c is the rated capacity of the remaining capacitor bank, X0 is the comprehensive reactance, n min It is the lowest gear of 110kV transformer.

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