GB 25974.4-2026Powered support for coal mine - Part 4:Specification for electro-hydraulic control system (English PDF)

4.1 General Requirements

4.1.1 Lightning protection measures should be provided at the transmission interface, wellhead, power supply, etc.

4.1.2 During use, the system should have the function of protecting operators from mechanical and electrical injuries.

4.1.3 Pressure sensors used in hydraulic support columns shall comply with the following regulations.

a) The pressure sensor's range is not less than 60 MPa;

b) Measurement error not greater than ±2%FS;

c) No leakage or damage occurs when the load pressure reaches twice the full scale.

4.1.4 The human-machine interface unit of the hydraulic support control device shall at least include an emergency stop mechanism and a locking mechanism, and shall be installed in a location easily accessible to the user. The emergency stop mechanism should be red when the operation is initiated.

4.1.5 Each hydraulic support control device should have a unique network communication address, and the hydraulic support and its control device should form a unique pair within the system. The logical relationships are as follows: The system composition is specified in Appendix A.

4.1.6 Electro-hydraulic directional valves shall comply with the provisions of GB/T 25974.3 and MT209.

4.1.7 The hydraulic support pushing cylinder should be equipped with an independent stroke detection sensor, and the sensor measurement error should not exceed 5mm.

4.1.8 The system shall have a coal mining machine position detection sensor. The coal mining machine position measurement error shall not exceed 1.5m.

4.1.9 The system shall have an angle sensor. The angle measurement error shall not exceed ±1°.

4.1.10 The system shall have a height sensor. The height measurement error shall not exceed ±1%FS.

4.2 Environmental Conditions

4.2.1 Unless otherwise specified in relevant documents, products used in the system for underground coal mines shall operate normally under the following environmental conditions.

a) Ambient temperature. 0°C~ 40°C;

b) Average relative humidity. not greater than 95% (25°C);

c) Atmospheric pressure. 80 kPa ~ 106 kPa;

d) Coal mines are environments with explosion hazards such as gas and coal dust;

e) Places free from corrosive gases that damage metals and insulation materials.

4.2.2 The storage and transportation conditions that coal mine products should withstand are as follows:

a) Ambient temperature. -40°C to 60°C;

b) Average relative humidity. not greater than 95% (25°C);

c) Vibration. Acceleration not exceeding 50 m/s^2;

d) Impact. Peak acceleration not greater than 500 m/s^2.

4.2.3 Equipment used in the computer room and dispatch room of the system should operate normally under the following environmental conditions.

a) Ambient temperature. 15°C~30°C;

b) Relative humidity. 40%~70%;

4.3 Power Supply

4.3.1 The AC power supply for downhole equipment shall comply with the following regulations.

a) Voltage. Permissible fluctuation range 75%~110%;

b) Frequency. 50Hz, allowable deviation ±5%;

c) Harmonics. not greater than 10%.

4.3.2 The AC power supply for ground equipment shall comply with the following regulations.

a) Voltage. Permissible fluctuation range 90%~110%;

b) Frequency. 50Hz, allowable deviation ±5%;

c) Harmonics. not greater than 5%.

4.4 System Functional Requirements

4.4.1 The system should have data acquisition, processing, display and alarm functions.

4.4.2 The system should have stop, interlock, and emergency stop functions, and should also have the function of displaying the emergency stop and interlock trigger positions. (Emergency stop function) Its priority should be higher than that of the interlocking function.

4.4.3 The system should have an automatic pressure compensation function.

Note. Automatic pressure compensation is achieved by automatically monitoring the pressure of the hydraulic support column or front beam jacks through a pressure sensor. When the supporting pressure of the column or front beam jacks is low... When the set pressure value is reached, the system automatically opens the liquid inlet circuit of the column or front beam jack until the pressure of the column or front beam jack reaches the set value.

4.4.4 The system should have the function of storing and querying information on the movement and status of hydraulic supports.

4.4.5 The system should have a program upgrade function.

4.4.6 The system should have equipment self-testing and network integrity monitoring functions.

4.4.7 System parameters shall comply with the following requirements.

a) Parameter modification supports both single-frame and batch modification functions;

b) The parameter modification has operation permission management and operation log functions.

4.4.8 The monitoring data of the system shall comply with the following provisions.

a) The data consists of three parts. data value, timestamp, and status identifier;

b) Alarm logs include alarm time, alarm type, alarm level, alarm confirmation time, confirming user, confirmation information, etc.

c) Operation logs include operation time, operation type, operation event, etc.

4.5 Main Technical Specifications

4.5.1 The hysteresis time of the electro-hydraulic directional valve should not exceed 300ms.

4.5.2 The start-up response time of the electro-hydraulic directional valve should not exceed 150ms.

4.5.3 The remote control response time of the system should not exceed 1 second.

Note. Remote control response time refers to the time required from when the system's centralized control device issues a control command to when the electro-hydraulic directional valve of the hydraulic support executes the action.

4.5.4 The system emergency stop response time should not exceed 1 second.

4.5.5 The stop response time should not exceed 500ms.

4.5.6 An audible alarm signal, clearly distinguishable from other surrounding noises, should be present in the pedestrian walkway of the hydraulic support. The audible and visual alarm should be within a certain distance. The sound level at 1m from the unit should be greater than 85dB and less than 118dB (A-weighted); the light alarm signal should be visible at 20m in the dark.

4.5.7 The maximum monitoring capacity of the system should be no less than 250.

4.5.8 The automatic program control of hydraulic supports should have an action warning function, and the warning time should be no less than 2 seconds.

4.6 Power fluctuation adaptability Within the voltage fluctuation range specified in 4.3, the system's technical requirements and main technical indicators shall comply with the provisions of

4.7 Operational stability The system should undergo a continuous operation stability test for 7 days, with checks performed daily. The system's technical requirements and main technical specifications should be specified. The standard shall comply with the provisions of

4.8.1 When conducting immunity tests as described in

4.8.2 to 4.8.9, the test results should be based on the electrical performance or functional degradation of the system under test during the test. The elephants are classified, and their specific performance levels are determined as follows:

---Class A. The tested system exhibits normal explosion-proof performance after the test, and its electrical performance and functions are normal during and after the test;

---Class B. The tested system exhibits normal explosion-proof performance after the test, but its electrical performance is reduced or it loses function during the test. No further operation is required after the test. The hydraulic support should recover on its own with the intervention of the staff, but no unexpected movements should occur during or after the test.

4.8.2 Ground-based equipment shall be able to pass the electrostatic discharge immunity test of level 3 as specified in GB/T 17626.2, and be evaluated accordingly. Grade A.

4.8.3 The system shall be able to pass the radio frequency electromagnetic field radiation immunity test of level 2 as specified in GB/T 17626.3, with an evaluation level of A.

4.8.4 The system should be able to pass the electrical fast transient/burst immunity test of level 2 as specified in GB/T 17626.4, and be evaluated accordingly. The grade is A.

4.8.5 The system's AC power port shall be able to pass the surge (impulse) immunity test of level 3 as specified in GB/T 17626.5. The system's DC power supply port and signal port should be able to pass the test of level 2 as specified in GB/T 17626.5, with an evaluation grade of B. The surge (impact) immunity test was rated as B.

4.8.6 The system should be able to pass the conducted interference immunity test for radio frequency field induction at test level 3 as specified in GB/T 17626.6. The price rating is A.

4.8.7 The system shall be able to pass the power frequency magnetic field immunity test of level 3 as specified in GB/T 17626.8, with an evaluation level of A.

4.8.8 The system shall be able to withstand voltage dips of 30% at the AC port for

0.5 cycles as specified in GB/T 17626.11. Voltage dip immunity test, rated A; voltage dip immunity test with a 60% reduction for 5 consecutive cycles, rated B; AC port voltage drop A voltage interruption test with a voltage of 95% or lower for 250 consecutive cycles is rated as B.

4.8.9 The system shall be able to pass the test level 3 specified in GB/T 17626.13 for low-frequency AC port harmonics, interharmonics, and mains signals. Frequency immunity test, evaluation level is A.

4.9 Explosion-proof performance

4.9.1 Explosion-proof equipment shall comply with the provisions of KA25-2025 and related standards.

4.9.2 The system shall pass the intrinsic safety correlation test.

5.1 Test Conditions

5.1.1 Environmental conditions Unless otherwise specified in environmental testing or relevant standards, the tests shall be conducted under the following environmental conditions.

a) Ambient temperature. 15°C~35°C;

b) Relative humidity. 45%~75%;

c) Atmospheric pressure. 80 kPa~106 kPa.

5.1.2 Power Supply Conditions Unless otherwise specified in the relevant standards, the AC power supply for testing shall meet the following requirements.

a) Voltage. error not exceeding 2%;

b) Frequency. 50Hz, with an error of no more than 1%;

c) Harmonics. not greater than 5%.

5.1.3 Test Instruments and Equipment

5.1.3.1 The accuracy of the testing instruments and equipment shall meet the accuracy requirements of the measured performance.

5.1.3.2 The performance of the testing instruments and equipment shall conform to the characteristics of the performance to be measured.

5.1.3.3 The configuration of the testing instruments and equipment should not affect the measurement results.

5.2 Test System

5.2.1 General Requirements The equipment in the test system should be products that have passed factory inspection and type inspection.

5.2.2 Equipment Configuration of the Test System During factory inspection and type testing of a system, a test system should include no less than two maximum combined loads and their accessories.

5.2.3 Connection of the test system During testing, the system is tested according to its actual configuration. The system test connection diagram is shown in Figure 1. Index number explanation. 1

---Hydraulic support control device. a. Simulation lines using optical signal transmission can be simulated using optical attenuators, while simulation lines using cable transmission should meet the cable parameter design requirements. b. The maximum combined load should include the maximum load device that an intrinsically safe circuit can connect to, as determined by the manufacturer. Figure

5.2.4 Test System Operation Check

5.2.4.1 The test system shall be connected in accordance with the requirements of 5.2.3.

5.2.4.2 After running the check procedure once, the system should be able to operate normally as required and reflect the status of each component within the system correctly.

5.2.4.3 The inspection procedure shall comply with the following provisions.

a) Promptly provide information on normal operation and the working status of the parts being inspected;

b) Able to check whether each hardware component of the system is functioning properly;

c) Able to check communication status;

d) Provide clear display, printing, and recording of the results of the inspection;

e) Check whether the principles and technical requirements for program development comply with the provisions of Appendix A of GB/T 9813.1-2016.

5.3 System Functional Test

5.3.1 Data acquisition, processing, display and alarm function test The experiment was conducted according to the following steps.

a) Change the sensor output value and within a specified time, view the corresponding data on display devices such as the human-machine interface unit and the system control unit. According to the data, determine whether the data is consistent with the sensor output value and whether it meets the error requirements;

b) If the sensor malfunctions beyond its limits or malfunctions, check the system display status and alarm signals to determine if they conform to the product manufacturer's declaration. Regulation;

c) Cancel the over-limit or abnormal fault, and check whether the displayed status and alarm signals are cancelled in accordance with the product manufacturer's statement.

5.3.2 Stop, interlock, and emergency stop function test The experiment was conducted according to the following steps.

a) Set the stop action range parameters, and the hydraulic support control device will start the automatic program control operation;

b) Press the stop mechanism on the specified hydraulic support control device, determine whether the automatic action being performed by the hydraulic support has terminated, and check... Check the system display status;

c) Press the locking mechanism on the specified hydraulic support control device, check the power supply of the drive unit, and check the system display status. and alarm signals;

d) Release the lockout state, check if the power supply to the drive unit has been restored, and check if the display status and alarm signals have been cleared;

e) Press the emergency stop mechanism on the specified hydraulic support control device, check the power supply of the drive unit, and check the system display status. and alarm signals;

f) Release the emergency stop state, restore the power supply to the drive unit, and check whether the display status and alarm signals have been cleared.

5.3.3 Automatic pressure compensation test The experiment was conducted according to the following steps.

a) Monitor the pressure of the hydraulic support column or front beam jacks to ensure that the column or front beam jacks maintain sufficient support strength for the roof. Within a safe pressure range;

b) Reduce the pressure on the hydraulic support column or the front beam jack to a value lower than the given pressure.