CN105548821A - Lightning arrester live detection method - Google Patents

Abstract

The invention discloses a live detection method of a lightning arrester, which belongs to the technical field of lightning arrester testing. The invention comprises the following steps: selecting the maintenance power supply voltage as the primary reference voltage; determining the theoretical phase difference between the selected maintenance power supply voltage and the primary side voltage of the main transformer of the substation to be tested according to the wiring mode of the transformer in the substation and each maintenance power supply box; The difference is to correct the primary reference voltage to obtain the secondary reference voltage, which is used as the reference voltage signal of the arrester live test device; the current is obtained from both ends of the discharge counter of the arrester as the current input signal of the arrester live test device, and then the resistance of the arrester current analysis. On the premise of ensuring the accuracy of the test results, the present invention reduces the risk of mis-touching and mis-wiring by taking the secondary reference voltage in the phase of the voltage transformer terminal, thereby reducing the difficulty of wiring and reducing potential safety hazards.

Description

A live detection method of lightning arrester

technical field

The invention belongs to the technical field of lightning arrester detection, and more specifically relates to a live detection method of lightning arresters.

Background technique

At present, the lightning arresters in the power system generally use metal oxide arresters (MOA), which are one of the important protection devices to ensure the safe operation of the power system. For metal oxide surge arresters that have been in operation for a long time, the internal zinc oxide resistors will gradually age, be damp or damaged, and their active power loss will increase significantly. By measuring the change of electrical parameters such as the resistive current of the arrester, the operation status of the MOA can be understood.

At present, the main maintenance methods of metal oxide arresters include power failure preventive test, full current online monitoring, resistive current live detection, infrared thermal imaging temperature measurement and other methods. The MOA preventive test (especially the arrester on the main transformer side) must be shut down, the main equipment will reduce the operational reliability of the equipment, and sometimes the main equipment cannot be shut down due to the limitation of the operation mode, so the arrester cannot be pre-tested on time. The live test of MOA can realize the test without power failure of the arrester, improve the work efficiency, and play a positive role in investigating the insulation defects of the arrester, so it becomes the first choice for field test.

The domestic power sector generally uses the method of detecting the resistive current of metal oxide arresters to diagnose its insulation condition. There are two main detection methods for MOA resistive current: one is the third harmonic analysis method, which believes that the third harmonic component of the arrester is the resistive current. This method is affected by the third harmonic content of the system voltage, and the accuracy of the measurement results is poor; two It is the angle difference method of the secondary connection of the voltage transformer, that is, the reference voltage signal is taken from the bus voltage transformer, and the current signal is taken from the lower end of the arrester. This method has high test accuracy and good measurement stability, but the reference voltage generally needs to lead out the secondary signal of the voltage transformer, and the lead-out cable is not only cumbersome to operate, but also has low work efficiency. Once improper operation will cause the secondary voltage short circuit of the voltage transformer and other faults The safe and stable operation of the power system, and with the rapid development of power grid construction, there are more and more high-voltage substations, the workload of substation maintenance increases, and the requirements for maintenance personnel also increase.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a live detection method for lightning arresters, which proposes a new reference voltage based on the theoretical basis of the existing angle difference method for measuring resistive current On the premise of ensuring the test accuracy and measurement stability, the selection method solves the problems of the existing detection methods such as cumbersome operation, low work efficiency, and low safety and reliability.

In order to achieve the above object, the technical solution adopted in the present invention is:

A live detection method for a lightning arrester, comprising the following steps:

Step 1: Select the maintenance power supply voltage as the primary reference voltage U ₁ ;

Step 2: According to the wiring mode of the transformer in the substation and each maintenance power box, determine the theoretical phase difference between the selected maintenance power supply voltage U ₁ and the primary side voltage U ₀ of the main transformer of the substation to be tested

Step 3: According to the phase difference Correct the primary reference voltage to obtain the secondary reference voltage U ₂ , which is used as the reference voltage U of the surge arrester live test device;

Step 4: Obtain the current from both ends of the discharge counter of the arrester as the current input signal I of the live test device of the arrester, and then analyze the resistive current of the arrester.

Preferably, the inspection power source described in step 1 is an AC power source in an inspection box corresponding to the main transformer to be tested.

The theoretical phase difference described in step 2 The specific performance is that the maintenance power supply voltage U ₁ is ahead of the phase difference of the primary side voltage U ₀ of the main transformer of the substation to be tested

The method of correcting the preliminary reference voltage described in step 3 is carried out according to the following formula:

In the formula: It is the phasor form of the primary side voltage U ₀ of the main transformer of the substation to be tested; _phasor form for the overhaul supply voltage U1.

The reference voltage U of the surge arrester live test device described in step 3 is "DL/T987-2005 General Technical Conditions for Zinc Oxide Arrester Resistive Current Tester" and "DL/T474.5-2006 On-site Insulation Test Implementation Guidelines for Lightning Arrester Tests" "The reference voltage input signal of the metal oxide arrester resistive current tester mentioned in ".

The specific method of obtaining current from both ends of the discharge counter of the arrester described in step 4 is that the current signal is obtained from both ends of the discharge counter of the arrester, the positive wire is clamped to the high voltage end of the discharge counter, and the negative wire is clamped to the ground terminal of the discharge counter.

The surge arrester live test devices described in step 3 and step 4 are "DL/T987-2005 General Technical Conditions for Zinc Oxide Arrester Resistive Current Tester" and "DL/T474.5-2006 On-site Insulation Test Implementation Guidelines for Lightning Arrester Test" The specialized metal oxide arrester resistive current tester described in includes various models of instruments with this function.

Generally speaking, compared with the prior art, the new detection method proposed by the present invention can obtain the following beneficial effects by using the overhaul power box wiring method instead of the voltage transformer secondary wiring method to obtain the reference voltage: effectively reducing the The personal safety and the safety of the power system that may be caused by the operation technology significantly reduce the complexity of the maintenance operation, improve the efficiency of the maintenance work, ensure the accuracy and accuracy of the test results, and reduce the loss of manpower and material resources caused by misoperation. Waste, and economic loss caused by power outage maintenance.

Description of drawings

Fig. 1 is a schematic flow chart of the detection method of the present invention;

Fig. 2 is the on-the-spot wiring schematic diagram of detection method of the present invention;

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

The invention is a new live detection method of a lightning arrester. On the basis of the existing theory, a method for carrying out live testing of the lightning arrester is proposed in a high-voltage substation by using a maintenance power box wiring method instead of a voltage transformer secondary wiring method. The invention reduces the operation difficulty of live detection of the lightning arrester, and reduces the safety hazards in the detection process.

Example 1:

In March 2015, three groups of 500kV surge arresters were tested in Jiangxia 500kV substation using the secondary wiring method of voltage transformer and the wiring method of maintenance power box. One group of resistive currents tested is shown in the table below . In the table, the resistive currents of A, B, and C phases differ by 3.3%, 4.0%, and 4.6%, respectively.

As can be seen from the table, compared with the existing voltage transformer secondary wiring method, the new method for detection of the arrester belt point proposed by the present invention has very little difference in test results. The change trend of the true value of the resistive current of the arrester can reflect the operating state of the arrester and meet the requirements of the field test.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention are all Should be included within the protection scope of the present invention.

Claims (7)

1. A lightning arrester live detection method, is characterized in that, described method comprises the following steps: Step 1: Select the maintenance power supply voltage as the primary reference voltage U ₁ ; Step 2: According to the wiring mode of the transformer in the substation and each maintenance power box, determine the theoretical amplitude difference and theoretical phase difference between the selected maintenance power supply voltage and the primary side voltage _U0 of the main transformer of the substation to be tested Step 3: According to the phase difference Correct the primary reference voltage to obtain the secondary reference voltage U ₂ , which is used as the reference voltage U of the lightning arrester live test device; Step 4: Obtain the current from both ends of the discharge counter of the arrester as the current input signal I of the live test device of the arrester, and then analyze the resistive current of the arrester. 2 . The live detection method of a lightning arrester according to claim 1 , wherein the maintenance power source in step 1 is an AC power source in a maintenance box corresponding to the main transformer to be tested. 3 . 3. a kind of surge arrester charging detection method as claimed in claim 1 is characterized in that, the theoretical phase difference described in step 2 The specific performance is that the maintenance power supply voltage U ₁ is ahead of the phase difference of the primary side voltage U ₀ of the main transformer of the substation to be tested 4. a kind of lightning arrester charging detection method as claimed in claim 1 is characterized in that, the preliminary reference voltage described in step 3 is carried out according to the following formula: In the formula: It is the phasor form of the primary side voltage U ₀ of the main transformer of the substation to be tested; _phasor form for the overhaul supply voltage U1. 5. a kind of surge arrester electrification detection method as claimed in claim 1 is characterized in that, the reference voltage U of the arrester electrification testing device described in step 3 is " DL/T987-2005 Zinc Oxide Arrester Resistive Current Tester Universal The reference voltage input signal of the metal oxide arrester resistive current tester mentioned in "Technical Conditions" and "DL/T474.5-2006 On-site Insulation Test Implementation Guidelines for Arrester Test". 6. A kind of lightning arrester electrification detection method as claimed in claim 1, is characterized in that, described in the step 4 obtains the current specific method from the discharge counter two ends of lightning arrester is that the current signal is obtained from the discharge counter two ends of lightning arrester, positive pole The wire clamp is connected to the high-voltage end of the discharge counter, and the negative wire is clamped to the ground terminal of the discharge counter. 7. A kind of surge arrester electrification detection method as described in claim 5 is characterized in that, described arrester electrification test device is " DL/T987-2005 Zinc Oxide Arrester Resistive Current Tester General Specifications " and " DL /T474.5-2006 On-site Insulation Test Implementation Guidelines Surge Arrester Test "Special metal oxide arrester resistive current tester, including various types of instruments with this function.