220 kv Substation, Everything You Need To Know

The 220 kV substation is a key link in China’s distribution network system, an important interface between the high-voltage transmission system and power users, and the stability of its operation has an important impact on the entire power application.

220 kv substation consists of transformer, transformer, switchgear, lightning protection equipment and other facilities. 220KV 110KV is the voltage of the substation into the power, in the long-distance transmission, the voltage is usually divided into several levels, commonly used in high-voltage transmission, more 10KV, 35KV, and 110KV/220KV substation is to transform the input voltage into low voltage to the next level of transmission .

This article will tell you all the problems of 220 kv substation in detail. To provide you with effective advice in the design and maintenance of 220 kv substations.

220 kv substation

Why choose daelim to supply transformers for your 220kv substation?

The working condition of the main transformer directly determines the operational stability of the 220 kV substation and is the most central link in its actual operation and maintenance.

Daelim has a wealth of experience to provide you with effective advice in the design and construction of 220kv substations, and our professional team of designers will provide you with customized transformer services. daelim’s transformers have been well used in North America, Europe, South America, Asia and many other regions, and we have a large system of distributors to provide you with reliable after-sales.

Table of Contents

What is the safety distance of 220kv substation?

220 kv substations

The safety distance of the 220 kV substation is 10 meters. National regulations: distance below 1kV is 4 meters, distance between 1-10kv is 6 meters, distance between 35-110kv is 8 meters, distance between 154-220kv is 10 meters, distance between 350-500kv is 15 meters.

The electromagnetic radiation intensity within one hundred meters of a 220 kV high-voltage line is greater than 0.4 micro Tesla.

1. Since the frequency of 220kV and 110kV substation power equipment is 50Hz, electromagnetic induction is generated. The actual effect on the surrounding area is mainly an electromagnetic induction effect rather than electromagnetic radiation. An obvious example is a numbness and pain that occurs in humid weather when the human body comes into contact with ungrounded metal objects working under high voltage overhead power lines for charging. This is an electromagnetic induction phenomenon, but its energy is very small, similar to the electrostatic effect generated when taking off a sweater in winter, and will not cause harm to the human body.

2. The frequency of substation power equipment is 50Hz, generating very low-frequency electromagnetic field, it is impossible to transfer energy in space in the form of electromagnetic waves; secondly, the industrial frequency energy is very small, poor spatial transmission capacity when the energy is small. Coupled with the shielding effect of the surrounding buildings, the electromagnetic impact doubled, its electromagnetic environmental impact can be negligible.

3. The impact of electromagnetic radiation on the human body is mainly thermal effects, the harm mainly occurs in the radio frequency electromagnetic field. Substation radiation belongs to the industrial frequency electromagnetic field, does not belong to the radio frequency electromagnetic field.

How to design 220 kv substation?

The 220 kv substation is determined as 220 kV, 110 kV side double busbar wiring, 10 kV side single busbar sectional wiring way, 220 kV in and out of the line 11, 110 kV in and out of the line 17, 10 kV in and out of the line eight. Although the wiring method is relatively more equipment, larger investment, but compared to the other two options, the special needs of power supply reliability is very necessary, and maintenance, commissioning is relatively flexible, a variety of voltage level wiring can be convenient for expansion and development.

Main transformer selection

220kV substation electrical equipment selection by the main wiring design and the size of the substation load, usually choose a combination of electrical equipment with a small footprint, so as to reduce the amount of land occupied as much as possible.

The design according to the area of the next 5 to 10 years planning load situation, and from the whole network, determine the rated capacity of the substation single main transformer is 240MVA, the design of the substation has 220kV, 110kV, 10kV three voltage levels, so the selection of three-winding transformers, check the relevant electrical primary part of the electrical equipment manual, select the current period of two 220 kv grade transformer main transformers, whose voltage level is 220±8×1.25%/115/10.5kV. subsequent can be developed into three 220 kv grade power transformers.

Short-circuit current calculation

Short-circuit current, as one of the three major calculations in the power system, is the basis for selecting electrical wiring methods, selecting electrical equipment, adjusting and calibrating relay protection, and is necessary to ensure the safe operation of the power system.

The power system mainly has three-phase short circuit, two-phase short circuit and single-phase short circuit, because the original short-circuit current calculation of the substation design does not take into account the cable resistance, which leads to errors in the selection and calibration of equipment, resulting in improper operation of equipment and equipment damage, therefore, the short-circuit current calculation needs to take into account the cable resistance in order to ensure safer substation operation.

In addition, since the single-phase short circuit of 220kV bus is the most serious case of short circuit, this paper will focus on the analysis of contact potential and stride potential during single-phase ground fault.

Design of lightning protection grounding device

(1) This design includes the whole station outdoor main grounding network, architecture, independent lightning rod, climbing ladder, buried pipe, fire pipeline, cable trench and other grounding design, the design is based on CDEGS software simulation to calculate the grounding resistance and other calculation results.

Calculation input parameters include: grounding device design according to 40 years of age.

220kV substation whole station laying main grounding network, after considering the seasonal coefficient (1.4) soil resistivity taken as

Starting and ending depth 0.0 to 3.0m and 3.0 to 30.0m.

The resistivity is taken as 40×1.4=56Ωm and 20×1.4=28Ωm; the horizontal grounding body adopts TJ-150 copper stranded wire, and the vertical grounding body adopts Φ14.2mm copper-plated steel rod, L=2.5m.

The main grounding network of 110kV distribution device building and other building buildings is 0.2m below the base plate of the civil foundation, and the rest of the area is 0.8m below the ground.

Vision 220kV busbar maximum short-circuit current of 47kA, equipment maximum short-circuit current of 47kA, short-circuit duration of 0.7s.

The maximum short-circuit current of 110kV busbar is 24kA, the maximum short-circuit current of equipment is 24kA, and the short-circuit duration is 0.7s.

(2) According to the original information, technical data and the main calculation principles, the calculated output results are

(1) Calculation of grounding resistance: known grounding network area S = 7,035m2; equivalent diameter of horizontal grounding electrode d = 0.0138m; horizontal grounding electrode burial depth h = 0.8m; total length of outer edge of grounding network Lp = 336m; total length of horizontal grounding electrode LC = 2.300m; total length of vertical grounding electrode: LR = 80m;.

According to “soil resistivity test report” the substation soil resistivity is 0 ~ 3m: 40Ωm; 3.0 ~ 30m: 20Ωm. considering 1.4 times the seasonal coefficient, this site soil resistivity take the value of 0 ~ 3m: 56Ωm; 3.0 ~ 30m: 20Ωm. so using CDEGS calculation of this site grounding resistance is 0.133Ω.

② ground potential calculation: shunt coefficient Sf to 0.4, 1.220kV bus single-phase short-circuit current of 47kA, the occurrence of ground fault flow through the neutral point of its equipment current 23.5kA. taking into account the DC offset of the grounding network into the ground the maximum ground fault asymmetric current rms, ground potential rise (GTR).

Secondly, the single-phase short-circuit current of the 110 kV bus is 24 kA, and the current flowing through the neutral point of the equipment in case of ground fault is 12 kA. Taking into account the maximum effective value of the ground fault asymmetric current via the grounding network with DC offset, the ground potential rise (GTR), it is not necessary to verify the contact potential difference and the step potential difference.

(iii) In addition, it is known from the calculation that the maximum calculated value of the maximum value of the stride potential within the substation enclosure is 204.8 V for a short circuit in the 220 kV side of the station.

(ii) The maximum calculated value of trans-step potential within the substation enclosure is 204.8V < the allowed value of 254V, so the trans-step potential meets the requirements.

But the maximum calculated value of contact potential appears in the four corners of the enclosure for 1 065.25V, and the maximum value of the remaining areas are greater than the allowable value of 219V, does not meet the requirements.

In this regard, according to the above calculation results and deviations, in order to be safe, it is necessary to take appropriate measures to solve. Contact potential over the range of countermeasures.

(1) in the station often maintain the channel, structure and operating mechanism around the laying of gravel, gravel as operating flooring, its thickness is not less than 20cm, its soil resistivity of about 5kΩ-m, so as to improve the allowable contact potential to 1 039V.

Except for the maximum calculated value of contact potential appears in the four corners of the enclosure, which does not meet the requirements, the remaining places are less than the allowed value of 1,039V, which meets the requirements.

Secondly, considering that there is no equipment such as operating mechanism box and terminal box within 1m of the four corners of the fence in the station, no measures can be taken.

In order to ensure safety, within 1m of the four corners of the fence laying arc-shaped voltage equalization network, so that the whole station contact potential to meet the requirements.

(2) In addition, if a short circuit occurs in the station will also lead to ground potential rise to > 2kV, so the location of the exit door of the substation can be laid in three strips of equal pressure connected with the grounding network;.

In order to avoid electric shocks caused by operating personnel contacting lamps and lanterns, can be set up under the outdoor lamps and lanterns will take cross-cross encrypted equal pressure processing;.

Secondly, should also be possible to ground the network of high potential lead out of the site after the low potential into the site of the facility to take effective isolation, the isolation equipment added to all in and out of the substation 380V/220V and below voltage levels of power, control and communication cables, and the connection of the station inside and outside the metal pipeline in the station, outside the boundary location with insulation section isolation, to prevent the transfer of potential transfer and cause harm, lightning protection design .

The design includes the design of direct lightning protection for the whole station area. There are four 35m high independent lightning rods set up for the whole station, which constitute direct lightning protection for outdoor electrical equipment, outdoor buildings and span lines.

The design of the station because the buildings are in the lightning rod protection range, it is not necessary to set up a lightning belt on the roof of the building. Lightning rod grounding in the construction must be in accordance with the design requirements.

Independent lightning rod and the connection point of the main grounding network to the neutral point of the transformer and the grounding point of the equipment below 35kV along the length of the grounding body should be ≥ 15m.

In order to reduce the contact potential and improve the contact potential allowable value, this site takes in the station often maintained channel, structure and operating mechanism around the paving of gravel, gravel as an operating floor, its thickness is not less than 20cm, its soil resistivity of about 5kΩm.

How to manage the infrastructure of 220kv substation?

The safety hazards appearing in substation infrastructure projects are basically similar, and each infrastructure project department should develop a corresponding safety management system in conjunction with its own project reality.

We provide you with suggestions from four perspectives: layered management, contingency planning, technical control, and capital management.

220 kv main power transformer

Layered management and strengthening inspection

Subdivided on the basis of the main safety framework, the owner party, the design party, the construction party, the supervision party and the consulting party make their own safety management rules for this project, the assessment system is implemented to the people, the management personnel of each party perform static and dynamic inspection, and a detailed safety inspection plan is made, the specific plan is as follows.

(1) Each party organizes a monthly safety inspection, implements stage inspections at different stages according to the progress of the project, evaluates the inspection results to form documents and submits them to the Safety Production Committee.

(2) Supervisory party to perform supervision tasks, the inspection results should be recorded (including side station records), the safety problems found, should be proposed to rectify the views and require the construction unit to rectify, and make a record of timely feedback to the safety committee.

(3) All parties to organize a monthly safety study to improve the safety awareness of personnel at all levels.

(4) The safety committee will take the lead to hold regular monthly safety meetings and form meeting documents for archiving.

Refine the emergency plan

The emergency plan cannot be on paper, and an emergency command center composed of the owner, designer, constructor, supervisor and consultant safety inspectors should be established, with on-site emergency disposal team and regular simulation accident drills.

Under the site emergency disposal group, there are various professional groups, members include medical first-aiders, communication liaison, defense team members, material supply, emergency team members, and each professional group emergency agency.

Strengthen quality and technical control

Organize quality supervision and control group, responsible for engineering systems, equipment construction, installation, commissioning quality management, regular quality supervision and management will be carried out to coordinate the problems existing during the construction of the project by various units.

Clarify the quality requirements for equipment in the bidding documents, and control the quality acceptance gates for the arrival of materials.

Construct according to the requirements of the design drawings, consult relevant information, find the problems that are prone to occur during the construction process, and organize professional and technical personnel in the engineering department to inspect and accept the construction quality.

Funds management

Establish assessment and reward mechanism, and reward the assessment cost to the units and individuals who find the hidden safety problems and make rationalized suggestions.

Incorporate project safety management costs into the project budget, subdivide them into each stage, and make them dedicated.

Control the daily expenses in each stage of the project, make comprehensive use of resources and reuse them, make plans on a monthly basis, and spend as needed.

Relay Protection System in 220 kV Substation

This paper expounds the characteristics and current situation of relay protection, the problems and Countermeasures in the relay protection system of 220kV substation, including excessive power resistance, system equipment problems of problems and Countermeasures in the relay protection system of 220kV substation, including excessive power resistance, system equipment problems of substation, abnormal transformer interference and basic data management.

power substation

Fault I: Excessive power resistance

Line ground fault problem is a common problem in 220kv substation, excessive resistance means that during certain transmission media, the line may then have some discharge phenomena.

Due to the influence of transient components and excessive current, etc. on the voltage, there is a chance that the voltage will be reduced to a certain extent, although the existence of this situation is not evident in the fault, but over time will also directly affect the normal operation of relay protection work.

When implementing protection work on relays, if the impedance value is fully utilized for protection work, it may increase the frequency when the distance protection exceeds the action.

This situation, for the differential protection, may lead to a relatively large braking current, resulting in the differential can not work properly.

Relative to the back protection work, if the zero sequence current as the basis to solve the problem of high resistance fault, should use the main protection in the zero sequence differential protection to achieve directly, so as to effectively avoid the occurrence of privacy high resistance fault due to overload reasons.

Once a high-resistance ground fault occurs, even if the number of voltage drops and falls is relatively small at that time, there is a chance that a large zero sequence current will be generated, and the fraction of the fault that wants to react will generally be taken in this way, while also having a high degree of sensitivity.

Solution:Reduce the grounding resistance of the substation

In the process of 220kV substation equipment operation, in order to ensure the normal operation of power equipment under the premise of ensuring good grounding, at the same time, the operating efficiency of the equipment will also be affected by the grounding resistance.

As the substation in order to improve the operating efficiency of the lightning rod equipment, in general the use of lightning arrester and transformer mostly, in the use of the process, the probability of current and electromagnetic generation is greater.

Therefore, in the use of 220kV substation equipment, should be appropriate to reduce the line grounding resistance, effectively reduce some of the risks that exist during the operation of the equipment, thereby reducing the frequency of equipment failures and enhance the anti-interference ability of the equipment.

Fault two: Substation system equipment problems

Substation in the normal operation process often stop working due to equipment failure, because the transformer low-voltage side is not double protection, but also no breaker failure effective solution, so lead to this situation.

If there is a problem with the transformer 10kV bus, the 10kV of the main transformer will discharge the fault by increasing the hours of side protection.

But 10kV measured overcurrent is not protected or the circuit breaker fails, and the fault generated on the low voltage side will not be discharged.

There is another situation, in the daily use of the transformer in the process of its withstand instantaneous inrush current is not strong, subject to the impact of the length of time will also be reduced.

A short circuit near the low-voltage side of the transformer and a long short-circuit time, it will be subject to a large amount of current impact, eventually leading to transformer burnout.

If a fault occurs in the interval of 10kV while the quality of distribution equipment is not high, it will lead to the failure of the busbar.

Solution:Reasonably set the potential surface of relay protection equipment

The 220kV substation equipment is mainly controlled centrally by computer technology, and all the electrical equipment and relay protection devices in the whole substation system are effectively grouped together and installed in the central controller, and their operation is managed centrally through the network. In such an information management mode, the potential surface of the relay protection device is the same as that of other devices.

Although this approach can improve the management and safety control of relay devices to a certain extent, it is not very practical. If a certain device fails, it will affect another device and other relay protection devices, and it also increases the scope of the impact of the failure, which leads to a series of problems among the devices and makes the relay devices not effectively play their own safety protection function.

Therefore, in order to make the relay work and anti-interference work of 220kV substation operate effectively, we should design the potential surface of relay protection device scientifically and reasonably according to the actual situation, and adjust the potential difference between them on the premise of normal operation of electrical protection device and other electrical equipment, so as to improve the working ability of relay equipment.

Fault 3: Transformer interference abnormalities

The magnetic field in the high and low voltage transformer of 220kV substation occupies a great dominant position, so as to realize the switching of high and low voltage currents by itself, so that the transmission energy generated by power generation can be converted to high and low voltage in the transformer, and then achieve the purpose of remote power transmission and signal transmission. Transmission system itself is the core of a power system work, to ensure that the power system can work properly has a great impact.

At the same time, the transmission system requires more maintenance and handling costs than other transmission systems, although only a “primary system” failure and electromagnetic interference with relay protection devices can cause short-circuit faults in the entire power system, if the transformer circuit breakers cut off, the government will have to invest a lot of money to carry out If the circuit breaker in the transformer is cut off, the government will have to invest a lot of money to maintain or replace the equipment, so it should ensure that the transformer is not disturbed by the magnetic field to avoid the situation that the transmission system of the entire substation does not operate normally.

Solution: Transformer protection measures

Protection transformer is a kind of electrical equipment composed of communication equipment, electrical appliances and protection facilities.

For the protection of the low-voltage side of the transformer should take certain measures, when the transformer problems, in general, you can take measures to remove the low-voltage side of the bus fault as soon as possible, for the low-voltage side of the bus for dual protection at the same time will also enhance the sensitivity of the circuit breaker. Compound voltage blocking overcurrent protection is a frequently used measure.

In the normal operation of the entire power system, generally can take two sets of independent relay protection equipment to protect the circuit breaker, when one set of faults and can not work properly, the other system will automatically disconnect the circuit breaker to improve the efficiency of the entire power system operation.

When the transformer high-voltage side in line with the voltage blocking overcurrent can not adequately sense the low-voltage bus, it will add a set of overcurrent protection on the low-voltage side of the transformer, in order to effectively avoid the impact between the two sets of protection devices, their AC and DC are independent systems.

Fault four. The basic information is not well managed

In most cases, if the secondary equipment files of some substations are not updated and perfected in a timely manner, it may make the relay protection staff maintain the system mainly on the basis of their own relevant experience, and the information and file records may be ignored as a result, leading to the lack, omission and omission of the situation subsequently.

When the project is completed and then inspected, the database information may be incomplete or the database version is old, which causes the whole system database confusion. When the relay protection device is accepted and the predictive inspection process is performed, various problems may occur.

For example, when relay devices are field tested, the results differ significantly from the trip matrix control figures, which is likely to directly cause problems in certain circuits.

When technicians put a lot of effort into finding out the relevant problems, they only superficially react to the relevant conditions and do not file the existing problems in time, and then have to re-check them when similar problems occur in the future, which will not only increase the workload, but also greatly reduce the work efficiency.

The incorrect method of data storage or disorder, and the mutilation and destruction of the value list in the relay protection will bring some misleading to the technicians.

Solution. Strengthen data management and improve the foundation

In the relay protection process, we should strengthen the collection of data and organize it into files, so as to improve the efficiency and integrity of data management. Regularly check the historical and operational data of relay protection to ensure the integrity of the data, and at the same time facilitate access by maintenance personnel, so that the work efficiency will be improved.

When maintenance personnel find that the data does not match the site, they should check strictly, modify some data in the data, and make a good backup. If there are more serious problems, the relevant materials should be submitted to the relevant departments in written form, so that the staff can easily view the information in the later work.

What is a 220 kv main transformer?

220 kv main transformers

The 220 kV main transformer is a critical component of a 220 kV substation and is prone to failure due to its long-term high voltage and high load conditions.

In order to ensure the normal and stable operation of 220 kV substations, it is necessary to ensure that the 220 kv main transformer is in good working condition.

Based on this, the power sector needs to take effective operation and maintenance measures for 220 kV substation 220 kv main transformer according to the actual situation.

Operation and maintenance of 220 kV substation 220 kv main transformer can not only ensure that the equipment works properly, but also effectively extend its service life.

From the 220 kV substation 220 kv main transformer operating environment and the completion of the work content, operation and maintenance need to be carried out from two aspects.

First, regular operation and maintenance, that is, in the fixed cycle of the 220 kv main transformer’s working condition and equipment performance testing, to play a role in the prevention of failure.

The second is contingent operation and maintenance, mainly according to the specific operating conditions of the equipment needs to carry out the necessary testing and maintenance, so as to ensure that the equipment is in good operating condition.

Based on this, the 220 kv main transformer maintenance content and basic principles need to be clear, so that in the actual operation and maintenance can be targeted, not only to highlight the focus of maintenance, but also to take into account the details of maintenance, to fully ensure the quality of maintenance.

In the process of troubleshooting, it is not only necessary to fully understand the fault situation and disposal methods, but also to strengthen certain performance aspects according to the actual situation of the equipment to make it more in line with the actual needs.

Common fault types of 220 kv main transformer

The analysis of common fault types of 220 kv main transformer can provide ideas and methods for rapid fault determination and effective maintenance treatment. By summarizing the past experience, the failure problems of 220 kV substation 220 kv main transformer mainly include the following.

First, the 220 kv main transformer long time overload operation equipment damage, performance decline, its operating efficiency and poor quality of work.

Second is the overexcitation phenomenon will occur in some large transformers work process, once the overexcitation phenomenon, will cause 220 kv main transformer overheating and other problems, affecting the normal operation of peripheral equipment;.

Third, some other common problems, such as oil tank pressure overload, winding overheating, oil temperature too high, cooling system failure, etc.

For the above 220 kv main transformer faults and problems, the equipment maintenance process needs to choose effective treatment methods according to the fault characteristics.

How to maintain the 220 kv main transformer?

220 kv main transformer

Principles of maintenance

Considering the core function and important value of 220 kV substation 220 kv main transformer in the whole power system, the maintenance of 220 kv main transformer must set the basic implementation principles, so as to implement the relevant principles into the specific operation and maintenance process, and fundamentally ensure the quality of maintenance.

(1) Periodicity principle

The principle of periodicity is to maintain the 220 kv main transformer after a period of fatigue and performance degradation, fixed period can make the relevant operation and maintenance work institutionalized, but also to facilitate the specific management and practical implementation.

(2) The principle of timeliness

When 220 kV substation 220 kv main transformer because of some uncertain reasons appear unstable working condition, it is necessary to carry out timely maintenance, the operation of a variety of small problems and signs of failure to effectively solve, prevent failure problems, so as to reduce the failure rate of 220 kV substation.

At the same time, the 220 kv main transformer and related equipment performance of the substation can be optimized.

(3) Targeted principle

The entire operation and maintenance work must adhere to the specific analysis of specific problems, only to ensure its relevance, so that the quality and efficiency of operation and maintenance is guaranteed.

For example, the core of 220 kv main transformer and its connected metal structure is prone to overheating problems, technical personnel need to analyze the specific impact of different situations to determine the nature and location of the fault, to lay the foundation for troubleshooting.

(4) Safety principle

220 kv main transformer must ensure the safety of the premise of various operations and maintenance operations, need to be combined with the specific circumstances (including operating conditions, equipment capacity, etc.) to carry out safety analysis, so that the safety performance of 220 kv main transformer is fully guaranteed.

In addition, the normal operation of the 220 kv main transformer must be used as the evaluation benchmark to analyze whether the transformer overcurrent and other problems are caused by external phase-to-phase short circuit, and deal with them according to the overcurrent protection disposal process to ensure the safe operation of the power system.

220 kv main transformer maintenance points

220 kv main power transformers

In the actual operation and maintenance of 220 kV substation 220 kv main transformer, it is necessary to make a reasonable plan for the performance and operation of 220 kv main transformer according to the actual needs, not only to clarify the content of all items of maintenance, but also to explain the maintenance process and standards in detail.

Highlights

The maintenance of the 220 kv main transformer in normal operation focuses on temperature, oil level, noise, etc. The monitoring of these parameters and the recording of relevant data are useful for timely detection of faults and solutions.

For example, if the oil level drops too fast and is much larger than the standard value, the sealing of the equipment needs to be checked to see if there are problems such as oil leakage.

The load of the 220 kv main transformer has a great influence on its operational stability and needs to be checked regularly. When an overload situation occurs, the load needs to be adjusted and controlled to keep it within the reasonable range to which the 220 kv main transformer is adapted.

This prevents the 220 kv main transformer from being overloaded for a long period of time, which can cause it to malfunction and reduce its service life.

The internal working condition of the 220 kv main transformer system needs to be monitored during operation and maintenance. When abnormal sounds are heard, such as bursting sounds and noise, it means that the operating condition of the 220 kv main transformer has problems. At this time, the switch needs to be turned off immediately, and the internal of the equipment needs to be thoroughly inspected to find out the cause of the abnormal noise and to solve the problem completely.

Specific measures

For 220 kV substation 220 kv main transformer in fault and non-fault state maintenance and repair constitute a comprehensive content of the entire operation and maintenance measures, these specific measures are the basic methods and main work ideas to be followed in the actual maintenance.

(1) Internal fault maintenance.

220 kV substation 220 kv main transformer internal fault, the cause of its generation is relatively easy to determine, the entire fault repair needs to be based on the mastery of the fault situation and understanding of the relevant content, maintenance personnel can be based on professional knowledge and experience to complete the assessment, take effective measures to deal with.

(2) Noise problem handling.

The 220 kv main transformer emits a variety of noise, and in normal operation, the situation where the equipment is noisy usually occurs only at the switching part. If other parts of the equipment are found to be noisy and the sound is different from normal operation, it can be considered as a fault, and it is necessary to judge the fault situation according to the part where the noise occurs and the noise situation, and take corresponding measures to investigate and repair the fault.

(3) Oil leakage condition inspection.

Oil leakage is one of the common faults of 220 kV substation 220 kv main transformer, so the oil leakage condition needs to be checked frequently. Specific inspection can be divided into three parts.

First, oil temperature, mainly by detecting oil temperature to determine the equipment operation status as well as the cooling system working status.

Second is the sound and casing, the sound state is normal, the casing of the tightness, contact situation, etc. for a thorough inspection.

Third is the cooling system, the normal functioning of the cooling system can guarantee the normal work of 220 kv main transformer, once the temperature is too high may lead to a decline in equipment performance and affect the stability of operation.

Need to pay special attention to the state of the oil quality needs special attention, the oil quality should be transparent slightly yellow texture when normal, if the oil level is lower than the normal height need to check the oil leakage problem, and vice versa to check whether the cooling device can work properly.

(4) Equipment maintenance and transformation.

The stage of maintenance and upkeep of the substation system requires the arrangement of professional staff responsible for daily protection and maintenance.

Relevant staff need to clarify the requirements and content of the maintenance and maintenance system, combined with the actual situation of each equipment, unified maintenance, in order to find faults and deal with them in a timely manner.

(5) Regular overhaul and maintenance.

Regular maintenance 220 kv main transformer not only can solve the fault in time, but also can extend the service life of the transformer, enhance the safety and stability of operation.

First, regularly check the gas content in the transformer oil, determine whether the transformer oil is deteriorated, test the physical properties of transformer oil, so that it maintains good insulation.

Second, regularly check the transformer bushing, coil, lightning rod and other parts of the insulation and grounding situation, timely detection of grounding resistance, check whether the parameters are normal, and check whether the connection between the bushing and the terminal is normal.

Third, check the operation of the transformer cooling system, ventilation condition, check the switch situation of each valve position, reasonably develop the inspection mechanism and results registration, so that the shift personnel and maintenance personnel are able to timely understand the working condition of the transformer.

Fourth, regularly arrange for major and minor repairs to the transformer to eliminate faults and potential dangers in a timely manner.

Precautions

(1) Daily management and preparation.

After the daily maintenance, the operation of the transformer needs to be registered to facilitate the subsequent processing. In case of transformer failure, management personnel need to report it in time for professional maintenance personnel to handle it.

(2) Maintenance personnel need to improve their own professional level and quality.

Power supply system and 220 kv main transformer structure is more complex, may appear more problems, maintenance personnel should have enough experience and the ability to deal with problems, in order to timely processing of the transformer.

Maintenance personnel should take the initiative to analyze, evaluate as well as monitor the problems that appear in the 220 kv main transformer, develop a reasonable plan and take targeted measures.

(3) Strengthen the inspection and monitoring of the sound of 220 kv main transformer.

In the daily operation process, 220 kv main transformer sound is generally at the power supply, the other places are basically no noise, if there is noise, that is, 220 kv main transformer problems, technical personnel should promptly take effective measures to deal with.

(4) in the transformer cleaning, need to pay attention to take the correct steps and methods.

In the actual operation process, troubleshooting needs to pay attention to more problems, maintenance personnel need to actively use their own professional skills and experience to ensure the normal operation of the transformer.

Conclusion

As the core equipment in 220 kV substation, the stable operation of 220 kv main transformer is the prerequisite for the normal power supply of the whole distribution system.

The operation and maintenance of 220 kV main transformer should be carried out under certain principles, not only taking into account the current working condition of the equipment, but also avoiding affecting the normal operation of other equipment in the substation.

At the same time, the processing of common faults of 220 kv main transformer needs to have certain target, and take targeted measures to solve them through comprehensive analysis of the factors affecting the faults.

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