Technical Applications on SOLDO SK70 and SQN1 limit switch with Surge Protection Device in Pneumatic Valve
With the increasingly stringent requirements of electromagnetic compatibility, localized instrumentation and control cabinets, the core part of the power plant, must pass the electromagnetic compatibility of equipment identification.
From the equipment identification, electromagnetic compatibility standards and practical application as well as test verification and other aspects, the nuclear power plant instrumentation and control cabinet in the surge protector analysis and summary clarified the cabinet in the anti-surge protector of several key points, for the future of the power plant instrumentation and control cabinet localization provides a good help and valuable experience.
There are different forms of surge protector circuits according to various needs. Its basic components are described above. A technically proficient lightning protection products researcher can design various circuits, similar to building blocks that can be assembled into different structural patterns. The main SPD circuits are single-phase, TN-C, and TN-S depending on the circuit system.
SOLDO SK70 and SQN1 limit switches are used in the process control system to monitor the valve\\\'s status. All kinds of different signals need to be equipped with anti-surge protectors for electromagnetic compatibility, lightning, anti-interference, etc., to ensure the accuracy of signals. In the explosion-proof area, it plays a vital role in protecting different actuators and the return signal module and ensuring the regular operation of all valves.
The first stage of surge protection device can be used to discharge the direct lightning current or when the power transmission line is subjected to a direct lightning strike to discharge enormous energy. The possibility of a direct lightning strike must be CLASS-I lightning protection.
The second stage of surge protection is a protective device against the residual voltage of the previous surge protector and induced lightning strikes in the area. When a significant lightning strike energy absorption occurs at the previous stage, a portion of the energy is quite large for the equipment or the third stage of the surge protector that will be conducted and needs to be further absorbed by the second stage. At the same time, after the first stage of surge protection, the transmission line will also sense lightning electromagnetic pulse radiation LEMP, when the line is long enough to sense the energy of the lightning and becomes large enough to require the second stage of the surge protector to implement the discharge of lightning energy further. The stage-three surge protector shields the LEMP and the residual lightning strike energy that passes through the second-stage surge protector.
SEVICON products
A complete set of products production and commissioning, including regulating valves (pneumatic, electric), switching valves (butterfly valves, ball valves), actuators (pneumatic, electric), and control schemes (airways, circuits).
Products agencies include Italy SOLDO limit switch box, the United States FLOWSERVE complete series of products, South Korea YTC full series of products, Spain JC valve, Germany P + F series of sensors, and Germany MHA high-pressure ball valve.
Selection of SOLDO SQ series - SPDT signal ground size
Data cable: requirements>2.5mm2; when the length is greater than 0.5m, the request is greater than 4mm2. YD/T5098-1998
Power cable:
if sectional area of the LIVE is S≤16mm2, the EARTH line is S;
if sectional area of the LIVE is 16mm2≤S≤35mm2, the EARTH line is 16mm2 ;
if sectional area of the LIVE is S≥35mm2, the EARTH line is S/2. GB 50054 Article 2.2.9
Selection of SOLDO SK series - NAMUR 8VDC signal ground size
Data cable: requirements>2.5mm2; when the length is greater than 0.5m, the request is greater than 4mm2. YD/T5098-1998
Power cable:
if sectional area of the LIVE is S≤16mm2, the EARTH line is S;
if sectional area of the LIVE is 16mm2≤S≤35mm2, the EARTH line is 16mm2 ;
if sectional area of the LIVE is S≥35mm2, the EARTH line is S/2. GB 50054 Article 2.2.9
The purpose is to prevent surge voltages from being conducted directly from the LPZ0 zone into the LPZ1 zone, limiting surge voltages of tens to hundreds of thousands of volts to 2500-3000V.
It is generally required that this power surge protection device has a maximum impact capacity of more than 100KA per phase and the necessary limited voltage is less than 2500V, called the CLASS I power surge protection device.
These electromagnetic surge protector are designed to withstand the high currents of lightning and induced lightning strikes and attract high energy surges, diverting large amounts of surge current to the ground.
They only provide limited voltage (when the impulse current flows through the power supply surge protector, the maximum voltage on the line is called the limit voltage) for the medium level of protection, because CLASS I protectors are mainly to absorb large inrush current, and they can not fully protect the sensitive electrical equipment inside the power supply system.
The first stage of the power supply surge protector can protect against 10/350μs and 100KA lightning waves, meeting the highest protection standards stipulated by the IEC.
The technical reference: the lightning flow rate is greater than or equal to 100KA (10/350μs); Residual voltage value is not more than 2.5KV; Response time is less than or equal to 100ns.
The purpose is to further limit the value of residual surge voltage through the first stage surge protector to 1500-2000V and to implement an elect-potential connection for LPZ1-LPZ2.
The power surge protector for distributing output of electrical cabinet used as the second stage protection should be a voltage-limiting power surge protector. The lightning current capacity should not be less than 20KA. The protector should be installed in the branch distribution area to supply power to important or sensitive electrical devices.
These power supply surge protectors better absorb the residual surge energy that passes through the surge discharger at the user\\\'s power supply entrance and effectively suppress transient over-voltage.
The maximum impact capacity required for the power surge protector used here is more than 45kA per phase, and the necessary limited voltage should be less than 1200V, called the CLASS II power surge protector.
The general user power supply system can achieve the second stage of protection and meet the requirements of electrical equipment operation.
The second-stage power supply lightning protection device adopts class C protection devices for phase-medium, phase-ground, and medium-ground full-mode protection. The main technical parameters are:
The lightning current capacity exceeds or is equal to 40KA (8/20μs).
Peak residual pressure is not more than 1000V.
The response time is less than 25ns.
The purpose is the ultimate means of protecting the equipment, reducing the value of the residual surge voltage to less than 1000V so that the surge energy will not damage the equipment.
For the AC power supply of electronic equipment, when the power surge protector installed at the inlet end of the cable is used as the third stage protection, it should be a series type voltage limiting power surge protector, and its lightning current capacity should not be less than 10KA.
The last defense can be used in the internal power supply, which is part of the electrical equipment with a built-in power supply lightning arrester to eliminate slight transient over-voltage.
The power surge protector used here requires a maximum impact capacity of 20KA or less per phase, and the required limiting voltage should be less than 1000V.
It’s necessary for some particularly important or sensitive electronic devices and electrical equipment to use third-stage protection to protect electrical equipment from transient over-voltages generated within the system.
For the rectifier power supply used in microwave communication equipment, mobile station communication equipment, and radar equipment, it is advisable to choose the DC power supply lightning arrester with working voltage as the final protection according to the protection need of its working voltage.
According to the voltage level of the protected equipment, if the two-level lightning protection can be achieved to limit the voltage below the voltage level of the equipment, only two levels of protection are needed; if the voltage level of the equipment is low, four or even above levels of protection may be required.
The fourth stage of protection its lightning current capacity should not be less than 5KA.
SOLDO limit switch is generally with third-stage protection surge protector, used for signal, module, special module protection, and all kinds of bus communication modules, including DCS, NET, Ethernet, as well as HART, FF, PROFIBUS, CANBUS, MODBUS, and so on.
Installation
1、SPD general installation requirements
The surge protector is mounted on a 35MM standard guide rail
For fixed SPD, the following steps as follows,
1）Determine the discharge current path.
2）Mark the wire at the end of the device that causes an additional voltage drop.
3）The PE conductor of each device should be marked to avoid unnecessary induction loops.
4）An equipotential connection is established between the device and the SPD.
5）Multiple levels of SPD energy coordination are required.
Some measurements are required to limit the inductive coupling between the installed protected part and the unprotected part of the device.
Restricting the closed-loop area and selecting the loop\\\'s angle can reduce the mutual inductance by sensing the source and sacrificing the separation of circuits. When the current-carrying component wire is part of a closed loop, the wire is close to the circuit, and the loop and induced voltage are reduced.
Generally, it is better to separate the protected wire from the unprotected one, which should be separated from the ground wire. Meanwhile, the necessary measurements should be made to avoid the transient orthogonal coupling between the power and communication cables.
Drawing of surge protector\\\'s installation
2、Selection of SPD signal ground size
Data cable: requirements>2.5mm2; when the length is greater than 0.5m, the request is greater than 4mm2. YD/T5098-1998
Power cable:
if sectional area of the LIVE is S≤16mm2, the EARTH line is S;
if sectional area of the LIVE is 16mm2≤S≤35mm2, the EARTH line is 16mm2 ;
if sectional area of the LIVE is S≥35mm2, the EARTH line is S/2. GB 50054 Article 2.2.9
Main parameters
1、Nominal Voltage(Un):This parameter indicates the type of protector that should be selected in information technology systems and refers to the practical value of the AC or DC voltage. Consistent with the rated voltage of the protected system
2、Nominal Voltage(Uc):The rated voltage can be applied to the specified end of the protector for a long time without causing changes in the characteristics of the protector and activating the maximum voltage practical value of the protective element.
3、Rated discharge current (ISN):The maximum impulse current peak value that the protector can withstand when the standard lightning wave with the waveform of 8/20μs is applied to the protector ten times.
4、Maximum discharge current (Imax): The maximum impulse current peak value that the protector can withstand when a standard lightning wave with a waveform of 8/20μs is applied to the protector once.
5、The level of voltage protection (Up): The maximum value of the protector in the following tests: 1KV/μs slope of sparking voltage; Residual voltage of rated discharge current.
6、Responding time (tA): The unique protective element\\\'s operating sensitivity and breakdown time, mainly reflected in the protector, vary at a particular time depending on the slope of du/dt or di/dt.
7、Data transfer rate (Vs) : it indicates how many bits are transferred in one second in bps, which is the reference value for the correct selection of the lightning protection device in the data transmission system, and the data transmission rate of the lightning protection device depends on the transmission mode of the system.
8、Insertion loss (Ae): The voltage ratio is about before and after protector insertion at a fixed frequency.
9、Return loss (Ar): It represents the proportion of the front wave reflected in the protection device (reflection point). It is a parameter that directly measures the compatibility of the protection device with the system impedance.
10、Maximum longitudinal discharge current: it refers to the peak value of the maximum impact current that the protector can withstand when the standard lightning wave with the waveform of 8/20μs is applied to the ground once per line.
11、Maximum transverse discharge current: it refers to the peak value of the maximum impact current that the protector can withstand when a standard lightning wave with a waveform of 8/20μs is applied between the wires.
12、In-line impedance: it’s the sum of the circuit impedance and inductive reactance flowing through the protector at a nominal voltage Un., also called "system impedance."
13、Peak discharge current: There are two types, one is rated discharge current Isn and the other is maximum discharge current Imax.
14、Leakage current: it refers to the direct current flowing through the protector at 75 or 80 nominal voltage (Un)
