SF6 gas density relay calibrator is applicable to the testing of SF6 gas density relay calibrator for power supply companies, joint ventures, joint ventures, and infrastructure installation and scientific research and debugging units. It is a kind of instrument that is specially used for detecting various types of SF6 gas density relays. Its main function is to measure the pressure value of SF6 gas density relay contact action, and is locked by the SF6 gas density relay calibrator according to the moment of contact action. The stored SF6 gas pressure value and temperature value are automatically converted to a standard pressure value corresponding to 20°C.
SF6 gas density relay calibrator test instructions:
1, measurement performance requirements
(1) Pressure indication error
The expression of pressure tolerance Δy is:
Δy=±a%F•S
a - Accuracy rating of the instrument being inspected (as specified in the product specification)
F•S——pressure range of the instrument being tested
(2) Pressure return error
The pressure return error should not exceed the absolute value of the allowable error of the pressure indication.
(3) Temperature measurement error
Temperature measurement error should not exceed ±0.05°C
(4) P20 indication error
The indication error of P20 displayed by the instrument under inspection shall not exceed the allowable error of pressure indication.
Note: The P20 value refers to the SF6 gas pressure value at 20°C when the SF6 gas density is constant.
(5) P20 conversion error
The scale error of P20 measured by the instrument being tested shall not exceed 1/2 of the allowable error of the pressure indication.
Note: P20 conversion error refers to the difference between the P20 value displayed on the tested instrument and the P20 value calculated by the standard device according to the pressure value and temperature value of the instrument being tested.
2. General technical requirements
(1) Appearance
(2) SF6 gas density relay calibrator shall be marked with product name, model specification, manufacturer or trademark, factory serial number, year of manufacture, etc.
a. The valve knobs, switches, connections (insertions), etc. on the instrument should be marked with the name. The assembly is reliable and the function is normal. There should be no loosening and damage.
b. The instrument display values ​​and symbols should be clear. There should be no missing strokes, overlapping characters, or uneven brightness. The panel should not have defects that affect the reading.
(3) Display value latch function check
When the input pressure makes a certain contact point move, the instrument should be able to lock the pressure value and temperature value of the corresponding contact action moment on the display.
3, detection conditions
(1) The standard device consists of three links: pressure measurement, temperature measurement, and P20 conversion. Each link should meet the following requirements: The absolute value of the pressure measurement allowable error should be less than 1/3 of the absolute value of the allowable error of the pressure indicator of the instrument being tested. Temperature measurement tolerance should not exceed ±0.05°C. P20 calculation error should be less than 0.0001MPa.
(2) Test environment
a. Ambient temperature 20±2°C
b. Relative humidity of the environment 45% to 75%
4, test items and detection methods
(1) Visual inspection
Visual inspection and manual examination
(2) Display value latch function check
Connect the plugs for the alarm and lockout test cords of the instrument to be connected to the corresponding sockets, turn on the power of the instrument, make the instrument in the measurement state, operate the pressure adjustment valve and the instrument function keys, and make the instrument display a certain pressure value and ambient temperature value. Then short the alarm and lockout test lines respectively.
(3) Pressure indication error detection
a, detection point selection
The detection point should not be less than 5 points (including zero) and More evenly distributed within the range. Two upper and lower stroke cycles are required for testing.
b. Detection method
Operate the pressure regulating valve so that the pressure is gradually raised point by point according to the pre-selected detection point, then step-by-point pressure, while reading the pressure of the standard device and the instrument under test at each detection point of the boost stroke and depressurization stroke Show the value and record it.
Repeat the measurement with the same method once, and take the large pressure indication error in the secondary measurement as the instrument's large pressure indication error.
c. Pressure indication error calculation
δ=P-P0
δ——Indicated error of the upper and lower strokes of each detected point of the instrument being inspected (MPa)
P——Pressure indication (MPa) of the upper and lower strokes at each detection point of the tested instrument
P0——Pressure indication of standard device (MPa)
(4) Pressure return error detection
The pressure return error can be calculated using the pressure indication error detection data, that is, the difference between the upper and lower stroke pressure indications at the same detection point.
Take the large return error in the secondary measurement as the instrument's large pressure return error.
(5) Determination of P20 indication error
a, detection point selection
The detection point should not be less than 3 points. Generally, it is selected according to the common contact action value of SF6 gas density relay.
Detection method
Operate the pressure regulator valve so that the pressure is gradually raised point by point according to the pre-selected detection point, and then step down, while reading the P20 indication value of the standard device and the tested instrument at each detection point, and record.
b, P20 value error calculation
Instrument P20 indication error (MPa)
Instrument to be detected P20 value (MPa)
Standard device P20 indication (MPa)
(6) Determination of P20 conversion error
The P20 value displayed on the instrument being tested and the value of P20 calculated by the standard device based on the pressure value and temperature value of the instrument being tested.
(7) Detection of temperature measurement error
Place the temperature sensor of the tested instrument and the temperature sensor of the standard device together in the thermostat. After the temperature of the sensor is stable, read the temperature display values ​​of the instrument under test and the standard device and record.
5, test results processing
(1) The data obtained from the test shall be corrected after calculation, and the number of digits to be rounded off shall be consistent with the resolution of the examined table.
(2) The tested SF6 gas density relay calibrator shall issue a test report.
6, the detection cycle
The detection cycle of the SF6 gas density relay calibrator is 1 year.
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Dongguan Huayuan Electronic Technology Co., Ltd , https://www.siliconefactory-oem.com