Rapid calculation method for relay protection constant value of 110kV transformer substation

Abstract

The invention relates to a rapid calculation method for a relay protection constant value of a 110kV transformer substation, and belongs to the technical field of relay protection. The method comprises the steps of data acquisition, rapid calculation model establishment, rapid calculation table making, filling and calculation and digital management. By means of the method, the calculation efficiency can be improved, the calculation workload is greatly reduced, errors prone to occurring in a traditional calculation method are avoided, and the calculation accuracy is improved. In addition, the calculation result is stored as an electronic document, subsequent consulting and management are facilitated, and digital management of constant value calculation is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of relay protection, and in particular relates to a 110kV substation relay protection setting fast calculation method. Background Art

[0002] With the comprehensive implementation of power system intensification and comprehensive automatic transformation projects, the fixed value calculation of 110kV substations has become increasingly complex and time-consuming. Traditional protection fixed value calculation relies on manual operation, which is not only large in calculation and prone to errors, but also difficult to achieve digital management. In addition, since most of the main transformers of 110kV and above are three-winding transformers, the number and variety of protection equipment in the station are large, which further increases the difficulty of calculation. Therefore, an efficient and accurate fixed value calculation method is urgently needed to solve the above problems. Summary of the invention

[0003] The present invention aims to provide a 110kV substation relay protection setting fast calculation method to solve the problems of large amount of calculation, easy error, difficulty in realizing digital management, etc. in traditional calculation methods.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A 110kV substation relay protection setting value rapid calculation method comprises the following steps:

[0006] Step 1: Data collection:

[0007] Organize and compile historical 110kV relay protection setting data, and extract key parameters that affect setting calculation;

[0008] Step 2: Establish a quick calculation model:

[0009] Based on the key parameters extracted in step 1, a quick calculation model is established; the quick calculation model includes differential starting quick calculation, ratio braking coefficient quick calculation, TA ratio coefficient and sensitivity verification quick calculation, backup protection setting quick calculation and capacitor quick calculation;

[0010] Step 3: Make a quick calculation table:

[0011] Based on the quick calculation model, prepare a detailed calculation table; the table should contain the necessary parameter filling area and calculation result area.

[0012] Step 4: Fill in and calculate:

[0013] In the parameter filling area, fill in the relevant parameters according to the form requirements;

[0014] Step 5: Digital management:

[0015] Save the calculation results as electronic documents and set corresponding permissions and backup strategies to ensure data security and traceability.

[0016] Further, preferably, in step one, the key parameters include the value of rated capacity, impedance voltage, load loss, high-voltage side voltage regulation range, medium-voltage side voltage regulation range, and 110kV bus impedance.

[0017] Further, preferably, in step 2, the differential start quick calculation is specifically:

[0018] Izd≥Krel*(Ker+△U1+△U2+△m)

[0019] Among them, Izd is the differential starting value; △U1 is the voltage regulation range on the high voltage side; △U2 is the voltage regulation range on the low voltage side; Krel is the reliability coefficient; Ker is the rated error limit coefficient of the current transformer; △m is the measurement error;

[0020] Further, preferably, in step 2, the ratio braking coefficient is quickly calculated as follows:

[0021] Kz≥Krel*(Kap*Kcc*Ker+△U1+△U2+△m)

[0022] Among them, Kz is the ratio braking coefficient; Kap is the ratio error coefficient of the current transformer; Kcc is the isotype coefficient of the current transformer; Ker is the rated error limit coefficient of the current transformer; △U1 is the voltage regulation range on the high voltage side; △U2 is the voltage regulation range on the low voltage side; Krel is the reliability coefficient; Ker is the rated error limit coefficient of the current transformer; △m is the measurement error.

[0023] Further, preferably, in step 2, the TA ratio coefficient and sensitivity verification quick calculation are specifically as follows:

[0024] High-pressure side balance coefficient KphH: KphH=1.732*U1nH*TA1nH / Sn

[0025] Medium pressure side balance coefficient KphM: KphM=1.732*U1nM*TA1nM / Sn

[0026] Low pressure side balance coefficient KphL: KphL = 1.732 * U1nL * TA1nL / Sn

[0027] Among them, U1nH is the rated voltage on the high voltage side, usually in kV; TA1nH is the transformation ratio of the current transformer on the high voltage side; Sn is the rated capacity of the equipment; U1nM is the rated voltage on the medium voltage side; TA1nM is the transformation ratio of the current transformer on the medium voltage side; U1nL is the rated voltage on the low voltage side; TA1nL is the transformation ratio of the current transformer on the low voltage side;

[0028] Klm = Ik.min / Id;

[0029] Among them, I d is the operating current of differential protection; Klm is the sensitivity; Ik.min is the minimum short-circuit current.

[0030] Furthermore, preferably, when a fault occurs on the 10 kV side, by calculating whether the sensitivity Klm is greater than 2, it can be determined whether the relay protection device is qualified in responding to the fault current.

[0031] Further, preferably, in step 2, the backup protection setting quick calculation is specifically:

[0032] When a single transformer is running, the low voltage fault is calculated with a fixed sensitivity of 1.5 times:

[0033] Izd≤Id.min1*5500 / (1.5*nTA):

[0034] When running in parallel, the low voltage fault is calculated with a fixed sensitivity of 1.5 times:

[0035] Izd≤Id.min2*5500 / (1.5*nTA),

[0036] Among them, Izd is the current setting value of the re-voltage overcurrent protection, Id.min1 is the minimum short-circuit current value when the single transformer is running, Id.min2 is the minimum short-circuit current value when the parallel transformer is running, and nTA is the transformation ratio of the current transformer;

[0037] The specific bus grounding alarm settings are: the voltage threshold of the bus grounding alarm is 26V, and the alarm delay time is 5s.

[0038] Further, preferably, in step 2, the capacitor quick calculation is specifically as follows:

[0039] Overvoltage protection: The voltage value is 1.1 times the rated voltage of the capacitor, and the time limit is 5s;

[0040] Low voltage protection: The voltage is 0.2 to 0.5 times the rated voltage of the capacitor; the current blocking current setting value is set according to the minimum working load current of the capacitor;

[0041] Unbalanced voltage protection: open triangle voltage is 5V, phase voltage differential protection is 3~5V, time limit value: 0.2s;

[0042] Zero-sequence overcurrent: 10kV is an ungrounded system and exits; 10kV is a low-resistance grounded system: the tripping section takes 60A and 0.4s, and the alarm section takes 10A and 4s.

[0043] Further, preferably, in step 4, for differential protection, it is necessary to manually fill in the excitation inrush current K*Ie.

[0044] Furthermore, preferably, in step five, the electronic document is an Excel spreadsheet.

[0045] In step 4 of the present invention, for equipment with a variable number of 10kV outgoing lines, the number of table rows can be adjusted according to actual conditions, and the formula can be copied for calculation.

[0046] The main transformer parameter table of the present invention should include parameters such as the main transformer rated capacity, high / low side rated current, impedance voltage Uk% and the like; the key parameter table should include parameters such as bus impedance, main transformer maximum voltage regulation range △U, and each TA ratio.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) Improve calculation efficiency: Through the quick calculation model and calculation table, the calculation workload is greatly reduced and the calculation efficiency is improved.

[0049] (2) Improve accuracy: It avoids the errors that are common in traditional calculation methods and improves calculation accuracy.

[0050] (3) Realize digital management: Save the calculation results as electronic documents for easy subsequent review and management, thus realizing digital management of fixed value calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a flow chart of the fast calculation method of relay protection setting value of 110kV substation of the present invention;

[0052] Figure 2 This is the differential protection action characteristic diagram. DETAILED DESCRIPTION

[0053] The present invention is further described in detail below in conjunction with embodiments.

[0054] Those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product specifications are used. If the manufacturer of the materials or equipment used is not specified, they are all conventional products that can be purchased.

[0055] Example 1

[0056] A 110kV substation relay protection setting value rapid calculation method comprises the following steps:

[0057] Step 1: Data collection:

[0058] Organize and compile historical 110kV relay protection setting data, and extract key parameters that affect setting calculation;

[0059] Step 2: Establish a quick calculation model:

[0060] Based on the key parameters extracted in step 1, a quick calculation model is established; the quick calculation model includes differential starting quick calculation, ratio braking coefficient quick calculation, TA ratio coefficient and sensitivity verification quick calculation, backup protection setting quick calculation and capacitor quick calculation;

[0061] Step 3: Make a quick calculation table:

[0062] According to the quick calculation model, formulate the corresponding calculation table; the table should contain the necessary parameter filling area and calculation result area;

[0063] Step 4: Fill in and calculate:

[0064] In the parameter filling area, fill in the relevant parameters according to the form requirements;

[0065] Step 5: Digital management:

[0066] Save the calculation results as electronic documents and set corresponding permissions and backup strategies to ensure data security and traceability.

[0067] Example 2

[0068] A 110kV substation relay protection setting value rapid calculation method comprises the following steps:

[0069] Step 1: Data collection:

[0070] Organize and compile historical 110kV relay protection setting data, and extract key parameters that affect setting calculation;

[0071] Step 2: Establish a quick calculation model:

[0072] Based on the key parameters extracted in step 1, a quick calculation model is established; the quick calculation model includes differential starting quick calculation, ratio braking coefficient quick calculation, TA ratio coefficient and sensitivity verification quick calculation, backup protection setting quick calculation and capacitor quick calculation;

[0073] Step 3: Make a quick calculation table:

[0074] According to the quick calculation model, formulate the corresponding calculation table; the table should contain the necessary parameter filling area and calculation result area;

[0075] Step 4: Fill in and calculate:

[0076] In the parameter filling area, fill in the relevant parameters according to the form requirements;

[0077] Step 5: Digital management:

[0078] Save the calculation results as electronic documents and set corresponding permissions and backup strategies to ensure data security and traceability.

[0079] In step one, the key parameters include rated capacity, impedance voltage, load loss, high-voltage side voltage regulation range, medium-voltage side voltage regulation range, and 110kV bus impedance value.

[0080] In step 2, the differential start quick calculation is as follows:

[0081] Izd≥Krel*(Ker+△U1+△U2+△m)

[0082] Among them, Izd is the differential starting value; △U1 is the voltage regulation range on the high voltage side; △U2 is the voltage regulation range on the low voltage side; Krel is the reliability coefficient; Ker is the rated error limit coefficient of the current transformer; △m is the measurement error.

[0083] In step 2, the ratio braking coefficient is calculated as follows:

[0084] Kz≥Krel*(Kap*Kcc*Ker+△U1+△U2+△m)

[0085] Among them, Kz is the ratio braking coefficient; Kap is the ratio error coefficient of the current transformer; Kcc is the isotype coefficient of the current transformer; Ker is the rated error limit coefficient of the current transformer; △U1 is the voltage regulation range on the high voltage side; △U2 is the voltage regulation range on the low voltage side; Krel is the reliability coefficient; Ker is the rated error limit coefficient of the current transformer; △m is the measurement error.

[0086] In step 2, the TA ratio coefficient and sensitivity verification quick calculation are as follows:

[0087] High-pressure side balance coefficient KphH: KphH=1.732*U1nH*TA1nH / Sn

[0088] Medium pressure side balance coefficient KphM: KphM=1.732*U1nM*TA1nM / Sn

[0089] Low pressure side balance coefficient KphL: KphL = 1.732 * U1nL * TA1nL / Sn

[0090] Among them, U1nH is the rated voltage on the high voltage side, usually in kV; TA1nH is the transformation ratio of the current transformer on the high voltage side; Sn is the rated capacity of the equipment; U1nM is the rated voltage on the medium voltage side; TA1nM is the transformation ratio of the current transformer on the medium voltage side; U1nL is the rated voltage on the low voltage side; TA1nL is the transformation ratio of the current transformer on the low voltage side;

[0091] Klm = Ik.min / Id;

[0092] Among them, I d is the operating current of differential protection; Klm is the sensitivity; Ik.min is the minimum short-circuit current.

[0093] When a fault occurs on the 10kV side, the calculated sensitivity Klm can be calculated to be greater than 2 to determine whether the relay protection device's ability to respond to the fault current is qualified.

[0094] In step 2, the quick calculation of backup protection setting is as follows:

[0095] When a single transformer is running, the low voltage fault is calculated with a fixed sensitivity of 1.5 times:

[0096] Izd≤Id.min1*5500 / (1.5*nTA):

[0097] When running in parallel, the low voltage fault is calculated with a fixed sensitivity of 1.5 times:

[0098] Izd≤Id.min2*5500 / (1.5*nTA),

[0099] Among them, Izd is the current setting value of the re-voltage overcurrent protection, Id.min1 is the minimum short-circuit current value when the single transformer is running, Id.min2 is the minimum short-circuit current value when the parallel transformer is running, and nTA is the transformation ratio of the current transformer;

[0100] The specific bus grounding alarm settings are: the voltage threshold of the bus grounding alarm is 26V, and the alarm delay time is 5s.

[0101] In step 2, the capacitor quick calculation is as follows:

[0102] Overvoltage protection: The voltage value is 1.1 times the rated voltage of the capacitor, and the time limit is 5s;

[0103] Low voltage protection: The voltage is 0.2 to 0.5 times the rated voltage of the capacitor; the current blocking current setting value is set according to the minimum working load current of the capacitor;

[0104] Unbalanced voltage protection: open triangle voltage is 5V, phase voltage differential protection is 3~5V, time limit value: 0.2s;

[0105] Zero-sequence overcurrent: 10kV is an ungrounded system and exits; 10kV is a low-resistance grounded system: the tripping section takes 60A and 0.4s, and the alarm section takes 10A and 4s.

[0106] In step 4, for differential protection, you need to manually fill in the excitation inrush current avoidance.

[0107] Application Examples

[0108] A 110kV substation relay protection setting value rapid calculation method comprises the following steps:

[0109] Step 1: Data collection:

[0110] The historical 110kV relay protection setting data were sorted and counted, and the key parameters affecting the setting calculation were extracted, including the rated capacity of the main transformer parameters, impedance voltage, load loss, high-voltage side voltage regulation range, medium-voltage side voltage regulation range, and 110kV bus impedance value.

[0111] Specifically, the historical 110kV relay protection constant data are sorted and counted, and the key parameters affecting the constant calculation are extracted, including the rated capacity of the main transformer parameters, impedance voltage, load loss, high-voltage side voltage regulation range, medium-voltage side voltage regulation range, and 110kV bus impedance value. A unified calculation model can be used to realize the constant calculation of differential protection parameters, 110kV bus differential protection, 35kV capacitors, 10kV outgoing lines, 10kV capacitors, 10kV#1 station transformer, 10kV#1 grounding transformer, 110kV standby automatic transfer, 35kV standby automatic transfer, and 10kV standby automatic transfer.

[0112] Step 2: Establish a quick calculation model:

[0113] A general quick calculation model is established based on the key parameters extracted in step 1. This model takes into account the differences between different protection devices, but the premise is that the differential setting is in Ie units.

[0114] The following are some key parameter calculation models for 110KV substations.

[0115] (1) Differential starting

[0116] Differential protection is a protection method based on the principle of current balance. It determines whether the equipment is faulty by comparing the current difference between the two sides or each phase of the protected equipment (such as transformers and lines). When the equipment is operating normally, the current flowing in and out is equal, and the differential current is zero; when a fault occurs inside the equipment, the differential current will no longer be zero. At this time, the differential protection device will operate to cut off the faulty equipment to protect the safe and stable operation of the power system. Calculate using the following quick calculation formula

[0117] Izd≥Krel*(Ker+△U1+△U2+△m)

[0118] Among them, Izd is the differential starting value; △U1 is the voltage regulation range on the high-voltage side; △U2 is the voltage regulation range on the low-voltage side; Krel is the reliability coefficient, which is used for differential starting value calculation in the 110kV substation protection setting calculation, and is fixed at 1.5 based on historical statistical values ​​and empirical values; Ker is the rated error limit coefficient of the current transformer, which indicates the maximum error of the current transformer under normal conditions, and is taken as 0.1; △m is the measurement error, which is taken as 0.05 based on historical statistical values.

[0119] (2) Ratio braking coefficient

[0120] Kz≥Krel*(Kap*Kcc*Ker+△U1+△U2+△m)

[0121] Among them, Kz is the ratio braking coefficient; Krel is the reliability coefficient. In the calculation of the protection setting of 110kV substation, according to historical statistical values ​​and experience, when used for the ratio braking coefficient calculation, 1.3 is taken for calculation to ensure the reliability of protection; Kap is the current transformer ratio error coefficient, which is taken as 2. Kcc is the same type coefficient of the current transformer, which is taken as 1. When the same model of current transformer is used, its value is usually 1; if different models are used, corresponding adjustments are required. Ker is the rated error limit coefficient of the current transformer, which indicates the maximum error of the current transformer under normal conditions, which is taken as 0.1. △U1 is the voltage regulation range on the high-voltage side; △U2 is the voltage regulation range on the low-voltage side; Δm is the measurement error, which is taken as 0.05 according to historical statistical values.

[0122] According to the above method, the constant values ​​of differential starting and ratio braking coefficient can be quickly obtained by only entering the high-pressure side voltage regulation range and the low-pressure side range.

[0123] (3) TA ratio coefficient and sensitivity verification

[0124] The TA ratio coefficient is the ratio of the primary current to the secondary current of the current transformer. It reflects the ability of the current transformer to convert high current into low current. Sensitivity verification is an indicator to measure the ability of the relay protection device to respond to fault current. It reflects whether the protection device can act promptly and accurately when a fault occurs. The TA ratio coefficient determines the accuracy of current measurement and the protection range of the relay protection device. Sensitivity verification can help optimize the setting of the relay protection setting and prevent false operation and refusal to operate.

[0125] like Figure 2 As shown, according to the current variation diagram, the inflection point Ir1 is fixed to 0.5Ie, and the inflection point Ir2 is fixed to 3Ie; the first slope is fixed to S at 0.5, and the second slope S1 is fixed to 1;

[0126] When the 10kV side fails: calculate whether the sensitivity Klm is greater than 2 to determine whether it is qualified;

[0127] Ik.min=Id.min*502 / nTA=(0.936*502) / 80 / 2.624=2.238Ie

[0128] Ir=0.5(︱2.238Ie︱+0+0)=1.119Ie

[0129] Id=(1.119Ie-0.5Ie)*0.5+0.5Ie=0.8095Ie

[0130] Klm=Ik.min / Id=2.238Ie / 0.8095Ie

[0131] Among them, S is the first slope; S1 is the second slope; Ik.min is the minimum short-circuit current; Ie is the rated current; Id.min is the minimum value of the differential current; nTA is the transformation ratio of the current transformer; Klm is the sensitivity coefficient; I d is the operating current of the differential protection, I r is the braking current of the differential protection; according to the above reasoning formula, the quick calculation formula of the sensitivity coefficient is Klm=Ik.min / Id=2.238Ie / 0.8095Ie.

[0132] TA ratio adjustment coefficient calculation (based on the high voltage side):

[0133] High-pressure side balance coefficient KphH: KphH=1.732*U1nH*TA1nH / Sn

[0134] Medium pressure side balance coefficient KphM: KphM=1.732*U1nM*TA1nM / Sn

[0135] Low pressure side balance coefficient KphL: KphL = 1.732 * U1nL * TA1nL / Sn

[0136] Among them, U1nH is the rated voltage on the high voltage side, usually in kV. TA1nH is the transformation ratio of the current transformer on the high voltage side (i.e. the ratio of the rated primary current to the secondary current). Sn is the rated capacity of the equipment, usually in MVA (megavolt-ampere) or kVA (kilovolt-ampere). U1nM is the rated voltage on the medium voltage side. TA 1nM is the transformation ratio of the current transformer on the medium voltage side. U1nL is the rated voltage on the low voltage side. TA1nL is the transformation ratio of the current transformer on the low voltage side.

[0137] These balance coefficients are used to convert electrical quantities at different voltage levels and current transformer ratios to the same reference for comparison or calculation.

[0138] (4) Backup protection setting

[0139] In the backup protection setting calculation, it is necessary to calculate the re-voltage overcurrent protection setting value. Based on experience and statistics, it is summarized into two situations: single transformer operation (i.e. only one transformer is running) and parallel operation (two transformers are running). This ensures that the protection can have sufficient sensitivity to operate when a low-voltage side fault occurs.

[0140] When a single transformer is running, the low voltage fault is calculated with a fixed sensitivity of 1.5 times:

[0141] Izd≤Id.min1*5500 / (1.5*nTA):

[0142] When running in parallel, the low voltage fault is calculated with a fixed sensitivity of 1.5 times:

[0143] Izd≤Id.min2*5500 / (1.5*nTA),

[0144] Among them, Izd is the current setting value of the combined overcurrent protection, Id.min1 is the minimum short-circuit current value when the single transformer is running, Id.min2 is the minimum short-circuit current value when the parallel transformer is running, and nTA is the transformation ratio of the current transformer. The calculated Izd value should be less than or equal to the minimum starting current value that the protection device can set to ensure that the protection can operate reliably when a fault occurs.

[0145] Busbar grounding alarm setting: Based on experience and statistics, the voltage threshold of the busbar grounding alarm is set to 26V, and the alarm delay time is set to 5s.

[0146] 26V: This is the voltage threshold for the busbar grounding alarm. When the busbar voltage drops below this value, the protection device will determine that the busbar may have a grounding fault and issue an alarm signal. This threshold is usually set based on the system's rated voltage and the allowable voltage fluctuation range to ensure that an alarm can be issued in the event of a real grounding fault, and no false alarm will be issued under normal voltage fluctuations.

[0147] 5S: This is the delay time of the alarm. Similar to the overload alarm, when the voltage is lower than the threshold, the protection device will also wait for a period of time (here 5 seconds) to confirm whether there is a ground fault.

[0148] The main function of the busbar grounding alarm is to remind the operation and maintenance personnel that a busbar grounding fault may have occurred and that measures need to be taken as soon as possible to investigate and handle it in order to avoid the fault from expanding or causing serious consequences such as equipment damage and personal injury.

[0149] (5) Capacitor

[0150] Based on experience and statistics, the following fixed values ​​can be directly calculated according to the following rules, avoiding the need to consult data and historical information.

[0151] Overvoltage protection: The voltage value is 1.1 times the rated voltage of the capacitor (line voltage), generally 115V (if the capacitor manufacturer has a recommended value, it should be set according to the recommended value), time limit value: 5s (tripping);

[0152] Low voltage protection: The voltage is 0.2~0.5 times the rated voltage of the capacitor (line voltage), generally 40V (if the capacitor manufacturer has a recommended value, it should be set according to the recommended value, but it must be greater than the no-pressure setting of the busbar where the capacitor is located), and coordinated with the sensitivity time limit of other equipment on the busbar; the current blocking current setting is set according to the minimum working load current of the capacitor, generally 0.2A~0.5A (secondary value)

[0153] Unbalanced voltage protection: Currently, 35kV capacitor banks in the grid use phase voltage differential protection, and 6-10kV capacitor banks use open triangle voltage protection. The voltage value is generally set according to the trip value provided by the capacitor manufacturer. If not provided, the empirical value is used. The open triangle voltage is 5V, the phase voltage differential protection is 3-5V, and the time limit value is 0.2s.

[0154] Zero-sequence overcurrent: 10kV is an ungrounded system, exit. 10kV is a low-resistance grounded system: the tripping stage takes 60A (primary value) and 0.4s (delay time); the alarm stage takes 10A (primary value) and 4s (delay time).

[0155] Step 3: Make a quick calculation table:

[0156] Based on the above key quick calculation models, a detailed spreadsheet is developed, including the "main transformer parameters", "differential protection" table, "TA ratio coefficient and sensitivity verification" table, "high backup protection", "low backup protection" table and "10kV outgoing line" table.

[0157] Step 4: Fill in and calculate:

[0158] Fill in the relevant basic parameters according to the requirements of the form and use the quick calculation model to perform calculations.

[0159] Step 5: Digital management:

[0160] Save the calculation results as electronic documents to realize digital management of fixed value calculations.

[0161] The collected and entered parameters are shown in Tables 1 and 2. The equipment set values ​​are automatically calculated based on the quick calculation model. Some of the set values ​​are shown in Tables 3 and 4.

[0162] Table 1#1 main transformer parameters

[0163]

[0164]

[0165] Table 2#1B short-circuit current calculation

[0166]

[0167] Table 3 Differential protection setting values

[0168]

[0169] Table 4 Backup protection setting value

[0170]

[0171]

[0172] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A 110kV substation relay protection setting value rapid calculation method, characterized in that: The steps include: Step 1: Data collection: Organize and compile historical 110kV relay protection setting data, and extract key parameters that affect setting calculation; Step 2: Establish a quick calculation model: Based on the key parameters extracted in step 1, a quick calculation model is established; the quick calculation model includes differential starting quick calculation, ratio braking coefficient quick calculation, TA ratio coefficient and sensitivity verification quick calculation, backup protection setting quick calculation and capacitor quick calculation; Step 3: Make a quick calculation table: According to the quick calculation model, formulate the corresponding calculation table; the table should contain the necessary parameter filling area and calculation result area; Step 4: Fill in and calculate: In the parameter filling area, fill in the relevant parameters according to the form requirements; Step 5: Digital management: Save the calculation results as electronic documents and set corresponding permissions and backup strategies to ensure data security and traceability.

2. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step one, the key parameters include rated capacity, impedance voltage, load loss, high-voltage side voltage regulation range, medium-voltage side voltage regulation range, and 110kV bus impedance value.

3. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step 2, the differential start quick calculation is as follows: Izd≥Krel*(Ker+△U1+△U2+△m) Among them, Izd is the differential starting value; △U1 is the voltage regulation range on the high voltage side; △U2 is the voltage regulation range on the low voltage side; Krel is the reliability coefficient; Ker is the rated error limit coefficient of the current transformer; △m is the measurement error.

4. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step 2, the ratio braking coefficient is calculated as follows: Kz≥Krel*(Kap*Kcc*Ker+△U1+△U2+△m) Among them, Kz is the ratio braking coefficient; Kap is the ratio error coefficient of the current transformer; Kcc is the isotype coefficient of the current transformer; Ker is the rated error limit coefficient of the current transformer; △U1 is the voltage regulation range on the high voltage side; △U2 is the voltage regulation range on the low voltage side; Krel is the reliability coefficient; Ker is the rated error limit coefficient of the current transformer; △m is the measurement error.

5. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step 2, the TA ratio coefficient and sensitivity verification quick calculation are as follows: High-pressure side balance coefficient KphH: KphH=1.732*U1nH*TA1nH / Sn Medium pressure side balance coefficient KphM: KphM=1.732*U1nM*TA1nM / Sn Low pressure side balance coefficient KphL: KphL=1.732*U1nL*TA1nL / Sn Among them, U1nH is the rated voltage on the high voltage side, usually in kV; TA1nH is the transformation ratio of the current transformer on the high voltage side; Sn is the rated capacity of the equipment; U1nM is the rated voltage on the medium voltage side; TA1nM is the transformation ratio of the current transformer on the medium voltage side; U1nL is the rated voltage on the low voltage side; TA1nL is the transformation ratio of the current transformer on the low voltage side; Klm=Ik.min / Id; Among them, I d is the operating current of differential protection; Klm is the sensitivity; Ik.min is the minimum short-circuit current.

6. The 110kV substation relay protection setting fast calculation method according to claim 5 is characterized in that: When a fault occurs on the 10kV side, the calculated sensitivity Klm can be calculated to be greater than 2 to determine whether the relay protection device's ability to respond to the fault current is qualified.

7. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step 2, the quick calculation of backup protection setting is as follows: When a single transformer is running, the low voltage fault is calculated with a fixed sensitivity of 1.5 times: Izd≤Id.min1*5500 / (1.5*nTA): When running in parallel, the low voltage fault is calculated with a fixed sensitivity of 1.5 times: Izd≤Id.min2*5500 / (1.5*nTA), Among them, Izd is the current setting value of the re-voltage overcurrent protection, Id.min1 is the minimum short-circuit current value when the single transformer is running, Id.min2 is the minimum short-circuit current value when the parallel transformer is running, and nTA is the transformation ratio of the current transformer; The specific bus grounding alarm settings are: the voltage threshold of the bus grounding alarm is 26V, and the alarm delay time is 5s.

8. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step 2, the capacitor quick calculation is as follows: Overvoltage protection: The voltage value is 1.1 times the rated voltage of the capacitor, and the time limit is 5s; Low voltage protection: The voltage is 0.2~0.5 times the rated voltage of the capacitor; the current blocking current setting value is set according to the minimum working load current of the capacitor; Unbalanced voltage protection: open triangle voltage is 5V, phase voltage differential protection is 3~5V, time limit value: 0.2s; Zero-sequence overcurrent: 10kV is an ungrounded system and exits; 10kV is a low-resistance grounded system: the tripping section takes 60A and 0.4s, and the alarm section takes 10A and 4s.

9. The 110kV substation relay protection setting fast calculation method according to claim 1 is characterized in that: In step 4, for differential protection, you need to manually fill in the excitation inrush current avoidance.

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