The low-voltage power distribution system may be charged during operation due to internal insulation damage or aging; the insulation level of the electrical product is reduced in a humid environment, and the product should not be charged with live parts; the power lead insulation damage and the outer casing will also collide Leakage current can be generated by charging the device case. Leakage will not only cause personal accidents, but also cause electric fires caused by leakage currents in China.
The use of residual current protectors (leakage protectors) is increasingly valued by electrical designers and users. When leakage current or electric shock current reaches the residual operating current value, the leakage release can quickly turn off the main circuit. Protective effects. However, in some occasions, the residual current protector that needs leakage alarm, but the main circuit should not be disconnected, that is, when the leakage current reaches the residual operating current, the protector only alarms, but does not trip.
2 Working principle of residual current operated circuit breaker 2.1 Working principle of ordinary residual current operated circuit breaker Any grid due to ground impedance (including grounding resistance and ground capacitance) cannot be infinite. Therefore, the ratio of the ground voltage to the ground impedance of the low-voltage power grid is called the leakage current. In the event of no accident such as personal electric shock or ground fault, the leakage current of the power grid to the ground is called leakage current (natural leakage). The normal leakage current of the distribution line and electrical equipment system must be less than the remaining non-operating current of the leakage protector.
See the working principle of the electromagnetic residual current operated circuit breaker. The normal three-phase leakage current is forbearance = L+4+ (where 夂, long, respectively, three-phase leakage current, and 4 is the total leakage current.
If it is a four-pole leakage protector, it is æ€ +4+1+4, of which 4 is the neutral current. If the three-phase leakage current is completely symmetrical, that is, the values ​​are equal, and the phase angle between them is 120°, the total leakage current is equal to zero. Since each relative insulation resistance is unlikely to be leakage tripping and the residual current circuit breaker that only alarms without tripping - Zhu Xiyu is completely equal, in the actual operating low-voltage power grid, the total leakage current is not equal to zero, called three-phase unbalance Leakage current. When a person touches the phase line or the phase has a ground fault, the relative leakage impedance will drop suddenly, forming an electric shock current or fault current I, at which time the grid leakage current. =夂+人.
In the figure: 1. Reaction force spring 2. Permanent magnet 3 demagnetization coil 4. Trip finger 5. Circuit breaker body lock 6. Circuit breaker main contact grid leakage current 4 is not only related to fault current 々 and original leakage current 丨. The value of the value is related to, and also related to the normal leakage current of the original grid and the phase of the fault current. The relationship between them is: within ±90°, regardless of the fault current (the size, the total leakage current after the fault is 4 Increase.
When the fault current is greater than twice the original normal leakage current, the total leakage current 故障 after the fault will increase regardless of the magnitude of 0.
The value of the fault current is in the range of 0~2/, and the phase difference varies from 90° to 270. There are some special cases: if /, =, and 0 is exactly ±12 (F, or r =20, when it is 180°, it will appear /=/. In the range of 12=~ 24°, even the case will occur, although in the specific conditions of these assumptions, these special cases can be theoretically explored, but in There is almost no practical significance in application. On the one hand, in the event of fault current Zhao Zhicheng Tian Zhongyi (67) 19, people cannot consciously determine the specific angle of 4. On the other hand, people always want to control the normal leakage current of the grid. The fault current in the actual fault is very large, and the greater the difference between the two, the higher the reliability of the fault protection.
When the medium leakage protector is in normal operation, if there is no leakage current on the load line, the vector sum of the primary conductor current should be zero, and the secondary side of the transformer with zero sequence current has no output signal, and the middle armature is replaced by the permanent magnet 2. Suction, so the trip finger 4 does not move, and the reaction force spring is tightened. 1. When someone is shocked or has a faulty current, the current vector sum of the primary wire is not zero, and the magnetic flux generated in the core is also It is not zero, and the residual current is induced in the secondary coil of the transformer, generating an induced potential. The larger the residual current, the larger the induced potential. The induced potential acts on the demagnetization coil 3 or on the circuit amplified by the electronic component (electronic leakage protector), generating a magnetic flux that cancels the permanent magnet 2 and attracts the magnet, releasing the reaction force of the spring 1 to release the armature The trip finger 4 impacts the circuit breaker lock 5 and is immediately unlocked, so that the link mechanism of the circuit breaker operates, and the main contact 6 is reliably opened. Thereby achieving the function of leakage protection. 2.2 The operating principle and the use situation of the residual current operated circuit breaker that does not trip only the alarm knows the leakage tripping principle of the ordinary residual current operated circuit breaker. It is very simple to understand the working principle of the residual current operated circuit breaker that only the alarm does not trip. It is. When a ground fault current occurs, the current vector sum of the primary conductor is not zero. The secondary side of the zero-sequence current transformer has an output signal, and the residual current is induced to generate an induced potential. The larger the residual current, the induced potential. The larger the induced potential acts on the demagnetization coil 3 or on the circuit amplified by the electronic component (electronic leakage protector), a magnetic flux that cancels the permanent magnet 2 to attract the armature, and releases the spring reaction force 1 to make the armature Release, these are exactly the same as ordinary residual current operated circuit breakers. However, the trip finger 4 is released due to the armature, impacting the alarm contact in the virtual frame (instead of the lock of the circuit breaker), so that the alarm contact is switched from the original S1 and S2, and the switch is switched to S1 and 53. The user can connect the light or the peak device or the alarm bell with the B3, and the auxiliary power supply can be used to achieve the alarm purpose of various requirements of the user. However, due to the overload of the main circuit, or the instantaneous tripping action of the armature due to the short circuit, the contact will still be normally opened, and the overload of the main circuit load will be delayed or instantaneously protected: this is completely related to the D-series leakage relay. Differently, when the D-type leakage relay is used alone, it can issue an alarm signal when an electric shock or ground fault occurs, but there is no protection function for the main circuit; only when used with a circuit breaker or a contactor, a pair of normally open through the leakage relay The 20 (68) switching contact is closed, and the signal caused by the fault leakage is output to the shunt release of the circuit breaker or the contactor, so that the main circuit is broken by the circuit breaker or the contactor.
In the figure: 1. reaction force spring 2. water long-term magnetic 佚 3. demagnetization coil 4. tripping finger 5. alarm contact only alarm non-tripping residual current action circuit breaker is applied in some special occasions: not due to leakage The power supply affects the emergency situation; the user receives the leakage alarm signal, and can timely repair the cause of the leakage according to the need to eliminate the fault.
Main application: fire power supply, such as fire elevator, fire pump, fire alarm and other equipment, fire and lighting; power supply for burglar alarm; power supply for hospital operating room and special equipment that does not allow power failure and equipment that will cause huge economic loss due to power outage .
3HSL1 series residual current operated circuit breaker HSL1 series residual current operated circuit breaker is a new product developed by our factory. It is suitable for AC 50Hz, rated insulation voltage 500V, rated working voltage 400V and below, rated current 6A to 200A, as a personal body. The electric shock and the leakage protection of the equipment can also prevent the fire hazard caused by the grounding fault caused by the insulation damage of the equipment. Under normal working conditions, it can also be used as infrequent switching (conversion) of lines and motors. When the line or motor is overloaded or short-circuited, it will automatically protect and cut off the circuit.
The main technical parameters of HSL1 series residual current operated circuit breaker are shown in Table 1. The breaking time of HSL1 residual current action is shown in Table 2. The breaking time of HSL1 delay type residual current action is shown in Table 3. HSL1 distribution protection circuit breaker main circuit The overload reverse time limit disconnection characteristic is shown in Table 4. The short circuit protection current setting value is 10% soil 20%; the overload reverse time limit disconnection characteristic of the motor protection circuit breaker main circuit is shown in Table 5, and the short circuit protection current setting value is 12M±20%. The time in Table 2 and Table 3 is the time when the residual current specified value is disconnected from the main contact of the circuit breaker, and the leakage current of HSL1 is tripped, and only the alarm for the remaining operating current due to the ground fault in HSL1 is not Tripped residual current operated circuit breaker, Table 1 Table frame rated rated insulation voltage G (V) Rated voltage (V) Rated current h Rated short-circuit breaking capacity Rated residual rated residual arc distance Model rated current rated frequency (Hz) Pole limit / operation L / L power factor action current (mA) does not operate current three-pole four-pole three-pole four-line raspberry 50 other residual operating current level by the user and the manufacturer negotiate ordering table 2 residual current most Breaking time (S) Note: 1 pair /A, 30mA circuit breaker with 0.25A instead of 5/.2 pair / An30mA circuit breaker with 0.5A instead of 10/A Table 3 Note: 1, 2 and Table 2 note the same as Table 4 test Current name setting current multiple agreement time start state agreement non-tripping current cold state convention tripping current hot state return characteristic current return time cold state Table 5 test current setting current appointment time starting state name multiple agreement non-tripping current cold State agreed trip current, hot return characteristic, current, hot state, cold state, can be understood as the time until each residual current specified value reaches the alarm start alarm.
Leakage Tripping and Residual Current Circuit Breaker with Alarm Only Tripping - Zhu Xiyu needs to point out that the HLS1 series frame currents 100A and 200A have both leakage tripping type and alarm-free tripping residual current operated circuit breakers. The residual current operated circuit breaker of the leakage trip can also be equipped with an alarm, but it is only when the main circuit is overloaded or the main contact of the circuit breaker is disconnected due to the leakage of the ground fault; the alarm is only the remaining without tripping. The current-operated circuit breaker, in addition to the alarm caused by the leakage of the ground fault (the circuit breaker does not trip), when the main circuit is overloaded (long delay or short-circuit transient), the circuit breaker can be re-installed, and a set of alarm contacts can be reloaded. And can alarm. The parameters of the alarm contacts in these cases are the same, see Table 6. Conventional heating current / "A) rated insulation voltage rated operating current U) Use HSL1 residual current action circuit breaker, during installation for a certain period of time (every other Month), when the switch is energized, press the test button, the general type can be normally disconnected; only the alarm does not trip the residual current action circuit breaker, then it will not be disconnected, and an alarm signal will be issued. To eliminate the alarm signal, The circuit breaker is released after being manually de-buckled and then resumed after closing.
The HSL1 series residual current operated circuit breaker manufactured by our factory has high limit breaking capacity. At present, the frame currents 63A, 100A and 200A have entered the market and are favored by users. In order to improve the entire series, the successful introduction of the residual current operated circuit breakers of the frame 400A, 630A and 800A is also just around the corner.
(Finish)
Gabion Box,Box Gabion,Gabion Wire Mesh Boxes,Gabion Rock Box
Anping County Hua Guang Wire Mesh Production Co.,Ltd , https://www.hgwirefence.com