National power system for SF6 equipment leak detection regulations?- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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National power system for SF6 equipment leak detection regulations?

发布时间：2017-05-15 来源：ydlcb 浏览次数：43次

What are the regulations on SF6 gas? See below:

Procedure for Electric Power Equipment Handover and Preventive Experiment is an important standard used in electric power production practice and scientific experiment. According to the basic spirit of DL/T "Preventive Test Regulations for Power Equipment" and GB 50150-2006 "Electrical Equipment handover Test Standard for Electrical Equipment Installation Engineering" and GB 12022-2006 industrial sulfur hexafluoride standard, revised in combination with the newly promulgated national standards, industry standards and anti-accident measures in the past two years. 1) SF6 gas transformer test project, cycle and standard SF6 gas test project (SF6 gas test project, cycle and standard during handover and operation)

2) SF6 current transformer test items, periods and standards for 110KV and above

Serial number	item	cycle	Standard	Instructions
2	SF6 gas leak	Handover, after overhaul, when necessary	Annual leakage rate is not more than 1%/ year, or according to manufacturer's requirements	Daily monitoring and testing if necessary.

3) Switchgear SF6 circuit breakers and GIS SF6 circuit breakers and GIS test items, cycles and standards.

Serial number	item	cycle	Standard	Instructions
2	SF6 gas leak	Handover, after overhaul, when necessary	The annual gas leakage rate is not more than 0.5% or the leak detector with a sensitivity of not less than 1×10-6 is used to detect no leakage of each sealing surface.	According to GB11023 method, the circuit breaker and GIS with higher voltage level can be detected by local bandaging method because of the large volume, and the SF6 gas content (volume ratio) measured is not more than 30×10-6 (each bandaging point) after 24 hours of bandaging at each sealing part.

3) Test items, periods and standards of metallide arresters for GIS

a) When the arrester is overrepair, its SF6 gas shall be specified in the above table

b) The sealing inspection during the operation of the arrester shall be as specified in the above table

c) Other related items shall be specified in the above table

4) << State Grid Corporation Power Equipment handover and preventive test Procedures >> Preparation instructions

SF6 Gas Leakage Clause under SF6 Circuit Breakers and GIS clearly states: At present, the sensitivity of SF6 leak detector has been high, can meet the annual leakage rate of no more than 0.5% of the requirements, and the original binding method is very inaccurate, the field implementation is difficult, the standard added "can be used sensitivity of not less than 1×10-6(volume ratio) leak detector to detect each sealing surface, there should be no leakage.

5) << State Grid Company power safety work Regulations (substation and power plant part)>> State Grid Company issued on sulfur hexafluoride electrical equipment work indoors, the equipment is filled with SF6 gas, the relative humidity of the surrounding environment should not be more than 80%, while the ventilation system should be turned on, and SF6 gas leakage into the work area should be avoided. The SF6 gas content in the air in the working area shall not exceed 1000UL/L (1000ppm). When the staff enters the SF6 distribution unit room, if there is no SF6 gas content display at the entrance, they should first ventilate for 15min and measure the SF6 gas content with a leak detector. Try to avoid one person entering the SF6 distribution unit room for inspection, and do not allow one person to enter the maintenance work. When entering the low area of SF6 distribution device or cable trench for work, the oxygen content (not less than 18%) and SF6 gas content (not more than 1000ppm) should be tested first.

The content and method of calculating the leakage amount and leakage rate of SF6

The sealing test is to determine whether the annual leakage rate of the gas chamber is qualified by detecting the leakage amount of SF6 gas. The control standard is that the annual leakage rate of each independent gas chamber is not more than 0.5%; For the calculation of SF6 leakage and leakage rate, generally using the dressing method (buckle method), which is a fine work, the leak detection tool used must be a quantitative leak detector, the accuracy must be higher than 1ppm, and it must be a stable detection tool.

The implementation procedure is: vacuum inspection →SF6 gas → leak inspection. The specific process is: After the GIS is tested by vacuum and the SF6 gas is stationary for 5h, the flange interface is wrapped with a plastic film, and the test is carried out after 24h.

Result determination

The local dressing method is used, and after 24h detection, if there is a concentration of SF6 gas in the film greater than 30ppm, the gas leakage rate of the gas chamber is unqualified. If the concentration of SF6 gas in all wrapped films is less than 30ppm, the gas leakage rate of the chamber is considered acceptable.

Calculation of air leakage:

G=(k/Δt)*v*ρ*t (g) (1)

Where :k= measured concentration value (volume ratio);

V= test volume (liters), equal to the volume of the cover minus the volume of the part under test, that is, v=v cover -v object under test

It should be noted that the v test object, when partially bandaged, the test object is only a part of the volume that is bandaged.

t= the working time of the tested object (hours), if the air leakage in a year, t=365*24=8760 hours

Δt= interval of measurement, if the test is performed 24 hours after bandaging, then Δt=24 hours

Calculation of air leakage rate

M=(g/Q)*100/%

Where Q= the total weight (grams) of SF6 gas filled into the equipment or container

Example: Measure the leakage rate of a group of 110 kV SF6 combined electrical outlet circuit

Known: cover volume V cover =29.0m3 Outlet loop volume V measured object =6.5m3, SF6 gas filled 120Kg

Δt=3.5 hours, ρ=sf6 density (6.14 g/L) measured concentration k=2*10-5

Find the annual leakage rate M

Solution :V= V cover =29.0m3-6.5m3=22.5m3= 22,500 liters, substitute (1)

g=(2*10-5*22500*6.14*24*365)/3.5= 6915g

From formula (2) :

M = 6915 / (120 * 1000) * 100% = 5.76%

The implementation procedure is: vacuum inspection →SF6 gas → leak inspection. The specific process is as follows: after the GIS is vacuum detected and the SF6 gas is stationary for 5h, the flange interface is wrapped with a plastic film, and the test is carried out after 24h. If the concentration of SF6 gas in a film is greater than 30ppm, the gas leakage rate of the air chamber is unqualified. If the concentration of SF6 gas in all wrapped films is less than 30ppm, the gas leakage rate of the chamber is considered acceptable.

It is recommended that enterprises adopt enterprise standards higher than this standard, and the contact method detection is not less than 1PPM. The bandaging method is not higher than 10PPM.