JB/T 5254-1991 Technical Specifications for Steam Turbine Overspeed Protection Devices JB/T5254-1991 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Steam Turbine Overspeed Protection Device
1 Subject Content and Scope of Application
This standard specifies the performance technical requirements, test items and requirements for steam turbine overspeed protection devices. JB5254-91
This standard applies to overspeed protection devices for fixed power generation steam turbines (hereinafter referred to as devices). Other types of steam turbines can also be used for reference.
2 Referenced Standards
GB1239
GB4058
JB4273
ZBK54022
JB2862
JB2901
3 Technical Requirements
Ordinary Cylindrical Helical Spring
Turbine Cleanliness Standard
Turbine Control System Performance Test Procedure
Turbine Assembly Technical Conditions|| tt||Technical conditions for steam turbine packaging
Technical conditions for steam turbine anti-rust
3.1 The steam turbine must be equipped with a mechanical emergency tripping device, and its operating speed is 108% to 112% of the rated speed. :3.2 When the rated power of the steam turbine is 25MW or above, it must be equipped with an additional overspeed protection device or an electric overspeed protection device. The operating speed of the additional overspeed protection device should be 1% to 2% higher than the operating speed of the emergency tripping device, but the maximum shall not exceed 3%. -3.3 When the rated power of the steam turbine is 50MW or above, it must be equipped with an electric overspeed protection device, and its operating speed should be set at the lower limit of the setting range of the operating speed of the emergency tripping device. bzxZ.net
3.4 ​​The working signals of the emergency tripping device, the additional overspeed protection device, and the electric overspeed protection device should be taken from their corresponding sensors respectively. 3.5 The above-mentioned overspeed protection device and the hydraulic emergency stop device together constitute the steam turbine overspeed protection system. 3.6 When the rated power of the steam turbine is 50MW or above, two mechanical emergency trip circuit breakers should generally be installed. As long as any one of them is actuated, the steam turbine can be shut down reliably.
3.7 The emergency trip circuit breaker should have means to adjust the actuation speed and meet the requirements of the actuation speed adjustment range of the emergency trip circuit breaker. 3.8 When the rated power of the steam turbine is 50MW or above, a device for online testing or a movable emergency trip circuit breaker impactor (flying ring) should generally be installed. If overspeed occurs during the test, the reliable shutdown of the steam turbine should still be ensured. 3.9 The emergency trip circuit breaker should be rigidly connected to the turbine shaft system. 3.10 The spring should meet the requirements of Class 1 accuracy in GB1239. After the emergency trip circuit breaker is tested and set, the screws and positioning pins should be caulked. 3.11
3.12 The reset speed of the emergency trip circuit breaker of large and medium-sized units should be greater than the rated speed. The reset speed of small units shall not be less than 97% of the rated speed.
3.13 The overspeed protection system shall be equipped with a local or controlled emergency shutdown device. 3.14 When the steam turbine is equipped with two emergency trip devices, two sets of the same emergency trip levers and slide valves shall be provided, and they can act directly or crosswise.
Approved by the Ministry of Machinery and Electronics Industry on 199107-0182
Implemented on 1992-07--01
JB5254-91
3.15 The assembly requirements between the emergency trip device and the emergency trip lever and slide valve shall comply with the provisions of ZBK54022. When the rated power of the steam turbine is 50MW and above, an overspeed test (speed increase test) device shall generally be provided. 3.16
3.17 When the steam turbine is equipped with two emergency trip devices, a dual-channel emergency trip action indicator shall be provided to monitor the action of the two impactors (flying rings) respectively. The indicator can be electrical, mechanical or hydraulic. The emergency trip indicator should emit a light signal when the impactor (flying ring) hits. The indication delay should not exceed 0.2s. 3.18
When the rated power of the turbine is 200MW and above, there should be a device to display and record the impactor (flying ring) hitting and resetting speed. The signal of the additional overspeed protection device should be taken from the governor. The action speed of the additional overspeed protection device should be able to be adjusted when the turbine is stationary, and the adjustment range should comply with the provisions of Article 3.2. The speed signal of the electric overspeed protection device must be taken from the sensor installed on the turbine. The power supply of the electric overspeed protection device must come from an uninterruptible power supply. The time from the turbine overspeed to the electric overspeed protection device sending a signal should be less than 10ms. The cleanliness of the device should comply with the provisions of JB4058. The device should also comply with the provisions of the national standard "Technical Conditions for Steam Turbine Safety Monitoring Devices". 3.27
Stroke, turning angle, operation direction, etc. should have clear and easily identifiable indication signs. 3.28
Related parts using two impactors (flying rings) should have clear distinguishing signs. Test items and requirements
Factory inspection test items
Emergency circuit breaker action speed setting test; additional overspeed protection device action speed setting test; electric overspeed protection device action speed setting test; d.
Extrusion test (oil injection test);
Overspeed test device test.
4.2 Emergency circuit breaker test includes extrusion test (oil injection test) and overspeed test (speed increase test). 4.3 It is prohibited to perform extrusion test (oil injection test) before overspeed test. 4.4 Overspeed test (speed increase test) should first use the synchronizer to increase the speed to a certain speed higher than the rated speed and then use the overspeed test device to continue to increase it to the emergency circuit breaker action. 4.5 Before the overspeed test (speed increase test), the emergency stop system must be reliable and the additional overspeed protection device action value must be correct. 4.6 The overspeed test (speed increase test) should be performed three times in a row under the same circumstances. The difference between the first two action speeds should not exceed 0.6% of the rated speed, and the difference between the third and the average of the first two should not exceed 1% of the rated speed. 4.7 The test setting value of the additional overspeed protection device shall comply with the provisions of Article 3.2. 4.8 The test setting value of the electric overspeed protection device shall comply with the provisions of Article 3.3. The emergency circuit breaker indicator test shall comply with the provisions of Article 3.8. 4.91
3 The test method shall comply with the provisions of JB4273.
5 Packaging and delivery
The packaging shall comply with the provisions of JB2862.
Rust prevention shall comply with the provisions of JB2901.
When the device leaves the factory, the following drawings and technical documents shall be provided with the steam turbine: a.
General drawing of the device;
Electrical schematic diagram;
Operation manual;
Factory certificate;
Packing list.
Additional remarks:
JB5254—91
This standard is proposed and managed by Shanghai Power Equipment Complete Design Institute of the Ministry of Machinery and Electronics Industry. This standard was jointly drafted by Dongfang Steam Turbine Factory and Shanghai Power Equipment Complete Design Institute. The drafting units of this standard include Nanjing Steam Turbine and Electric Motor Factory, Hangzhou Steam Turbine Factory, Shanghai Steam Turbine Factory, and Harbin Steam Turbine Factory. The drafters of this standard are Zhang Jiguo and Shao Pingshi. 84
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