Simply put, it is the function of fuse.
it was identified as a major equipment accident according to the original Regulation for Investigation of Production Accidents in Electric Power Industry. After the incident, experts, after many investigations and analysis, believe that the equipment's error-proof function is defective, and the failure to play an error-proof role is one of the main reasons for the accident. According to the relevant regulations, all high-voltage electrical equipment that may cause misoperation should be equipped with anti-misoperation devices and corresponding anti-misoperation electrical blocking circuits.
The anti-misoperation locking device in the production site mainly realizes five prevention functions: preventing the disconnector from being pulled and closed with load; Prevent closing with grounding wire (grounding switch); Prevent people from straying into the electrified interval; Prevent misoperation and misoperation of circuit breakers; Prevent live grounding wire (close grounding switch); And prevent non-synchronous juxtaposition. The basic method to realize non-synchronous parallel locking is to realize synchronous locking through differential pressure and frequency difference identification devices, and put in synchronous locking devices in time during switching operation to prevent non-synchronous closing of two systems with non-synchronous power supply.
the realization method and characteristics of five prevention functions. For manually operated switchgear, mechanical interlocking is generally achieved by mechanical means; The electrically operated switchgear is connected to the control loop through the auxiliary contacts in the auxiliary transfer switch of the circuit breaker according to a certain logical relationship, so as to realize the operation interlock.
what is the function of closing and locking?
closing locking is to prevent the circuit breaker from closing again after closing. That is, after closing, it is closed.
At the same time, there are different opinions about the function of closing and locking. Personally, I understand that closing locking means closing the circuit breaker again after closing to protect the circuit breaker mechanism from the impact of the circuit breaker's re-operation. Because the energy stored in the closing spring of the circuit breaker can ensure the energy needed for the closing operation of the circuit breaker and the energy needed for the opening operation (some of the remaining energy is absorbed by the buffer). Therefore, the circuit breaker is closed after reclosing to avoid the impact of strong spring energy on the mechanism. Therefore, closing and locking is by no means a function of preventing misoperation!
What do you mean by electrical locking? How is it connected? If there is a locking device, will it be all right in the future?
Electrical locking, as its name implies, is through electrical locking. It is necessary to find out the locking point and locking source, for example, the locking point is in the closing circuit, so that the closing circuit can not be closed, and it is generally between 11 and 13; Generally, the source of incoming line closing lockout is to collect isolation position, metering position, opening and closing state of sectional circuit breaker, etc. These auxiliary contacts are connected in the closing circuit. When the corresponding auxiliary contacts of these components are opened, it will not constitute the closing circuit, and a lockout will be formed.
Will it be all right if you have misoperation? Of course, a complete locking system can really ensure that misoperation is all right, because you will not succeed in misoperation and lock it, but in fact it is not the case at all, because China people know money and don't know responsibility, and the electrical equipment is generally untrustworthy, and the locking is not complete, and it is often missed. To put it bluntly, the locking is not complete, and it is almost more comprehensive for domestic equipment in the power system to encounter a locking.
the electrical locking depends on the actual site requirements, and the debugging of the electrical locking also depends on the site conditions, mainly depending on who built it for you, because the installation unit is closest to reality.
to sum up, whether the electrical locking in a station is comprehensive depends on the level of the installation unit, which has little to do with the design. The manufacturer only needs to lock inside a single device, and the installation and debugging unit is responsible for the overall situation, but the installation unit takes the least money, so don't expect a complete electrical locking to appear, and the probability is not much stronger than the probability of winning a lottery ticket every day.
What does it mean that the operating mechanism of circuit breaker is locked in power system?
Low-voltage frame circuit breaker is also called automatic switch. It is a switching appliance that can not only connect and disconnect normal load current and overload current, but also connect and disconnect short-circuit current. The low-voltage frame circuit breaker not only plays a control role in the circuit, but also has certain protection functions, such as overload, short circuit, undervoltage and leakage protection. Instantaneous locking of low-voltage frame circuit breaker refers to overload and short-circuit protection. Specifically: 1. Overload long delay protection. When thermal (bimetallic element) is used as overload long delay protection, its action source is I2R, and the effective value of AC current is equal to the average value of DC, so it can be used without any modification. However, for large current specifications, the secondary side current heater of current transformer can't be used because the transformer can't be used in DC circuit. If the overload and long delay release is fully electromagnetic (hydraulic, that is, oil cup type), the delay release characteristics will change, and the minimum operating current will increase by 11%-14%. Therefore, the AC full electromagnetic release cannot be used in DC circuits (if it is used, it will need to be redesigned). 2. Short circuit protection. The short-circuit protection of thermal-electromagnetic AC circuit breaker adopts magnet system, which is used in the filtered rectifier circuit (DC). It is necessary to multiply the setting current value of the original AC by a coefficient of 1.3. All-electromagnetic short-circuit protection is the same as thermal electromagnetic protection. Because DC current does not have the characteristics of zero crossing as AC, DC short-circuit current (even fault current with small multiple) is interrupted; It is difficult to extinguish the arc. Therefore, in addition to the traditional thermomagnetic release, an electronic release can also be used. An important advantage of the electronic release is that it can still work stably under the condition of environmental temperature change.
electrical locking and unlocking
electrical locking is not a narrow sense of closing and disconnecting, depending on where it is used. Generally, we can call all the conditions required for the electrical control outlet locking. For example, if relay K1 wants to act, relay K2 must be closed, so K2 is the locking condition of K1; if it is disconnected, it will be locked; if it is closed, it will be unlocked. On the other hand, if K2 is disconnected as the condition of K1 action, K2 is disconnected as unlocking and K2 is closed as locking. So it depends on the function of your pressure plate in the electrical circuit. Generally speaking, however, the pressure plate is mostly the function of functional input, that is to say, the pressure plate input is unlocking and the pressure plate opening is locking.
forgot to adopt it.
what is a locked loop
"locking" is a measure to prevent electrical misoperation. Our electrical operators are most afraid of misoperation, including:
1. Pull and close the disconnector with load;
2. Switch on with grounding wire (grounding knife);
3. Personnel mistakenly enter the electrified interval;
4. Misdividing and closing circuit breakers by mistake;
5, live ground wire (grounding knife).
and non-simultaneous juxtaposition.
Among them, locking includes: mechanical locking is a locking mode in which the mechanical structure of the operating mechanism of switchgear restricts each other, so as to achieve mutual interlocking.
electromagnetic locking is to use the auxiliary contacts of circuit breakers, disconnectors, circuit breaker doors, etc. to turn on or off the power supply of electromagnetic locks such as disconnectors and switch cabinet doors that need to be locked, so that their operating mechanisms cannot act, thus realizing the mutual locking between switching devices. The locking device is simple in principle and convenient to realize, and locking can be realized between different switchgear; It works well in a dry environment. However, due to our "national conditions", most of them are installed on indoor equipment of 35 kV and below. In use, due to various reasons, the auxiliary transfer switch can not be switched normally, and the electromagnetic lock can not meet the sealing requirements and is corroded by moisture, so that the locking often fails. For outdoor high-voltage switchgear, electrical logic locking is mostly used to prevent false locking.
the logic locking of electrical circuit is to use the auxiliary contacts of circuit breakers, disconnectors and other devices to connect to the electrically operated circuits such as disconnectors or grounding knife switches to be locked, so as to realize the mutual locking between switching devices. It is characterized by complex secondary circuit, heavy workload of installation and maintenance, and often requires the assistance or cooperation of maintenance comrades in order to eliminate locking failure in time. The basic condition for its realization is the electrically operated equipment and mechanism. At present, most outdoor switchgear of 33 kV and below use this kind of locking device, but the actual operation situation is far from the ideal target. The main factors are poor sealing, corrosion and improper switching of the auxiliary switch.
Frequent failures of electrical locking, electromagnetic locking and mechanical locking often force the brake switching operation to stop, and sometimes the technical director has to be asked to forcibly use the "master key" to unlock the operation or remove the locking device. In order to improve the difficult situation of anti-misoperation locking and the need of safe production, a microcomputer anti-misoperation locking system composed of main computer, computer key, electrical coding lock and mechanical coding lock has been applied and popularized. Microcomputer anti-misoperation locking system is to lock the circuit breaker, disconnector, grounding knife switch (grounding wire) and auxiliary contact of switch cabinet door (or combined with primary wiring simulation board) by microcomputer coding lock. Input the operating program (rules) or locking logic of the switchgear into the program lock through the software system for switching operation, that is, add the microcomputer five-prevention contact in the operating power circuit of the electrically operated breaker or the ground knife mechanism box, and the error prevention function is independently completed by the microcomputer five-prevention system. However, it is required that the microcomputer five-prevention system should have measures to prevent "idling (missing items during operation)" At present, microcomputer locking developed by a company in Zhuhai with relatively perfect functions is widely used in China. The application and popularization of microcomputer anti-misoperation locking system are restricted by its complicated operation, slow speed, difficult installation of coded locks and individual crashes.
first of all, it is necessary to ensure that the circuit wiring is correct and the locking device works well in the same period; If the primary wiring of the equipment is changed, or the circuit wiring of the same period is changed, it is necessary to phase or check the phase in time; The operator should be familiar with the synchronization point and synchronization circuit of the unit, and put an end to putting two synchronization power switches into operation in parallel at the same time; Manual synchronization operation should be identified in the same period to realize synchronization locking; It is forbidden to forcibly close the power supply tie line without simultaneous identification or permission from the superior dispatcher.
what does the lockout in the electrical industry mean? Can you use an easy-to-understand image metaphor?
The lock-up of the mutual gas industry, which is easy to understand, makes the electrical equipment locked and cannot be operated at will. Prevent personnel from misoperation.
the anti-misoperation locking device shall not be withdrawn from operation at will. When stopping the anti-misoperation locking device as a whole, it must be approved by the chief engineer, and at the same time, corresponding effective measures should be taken to prevent electrical misoperation; When the anti-misoperation device is abnormal, it is necessary to use the unlocking tool (key) or perform unlocking operation for emergency treatment of faults or other maintenance work, it is necessary to take corresponding safety measures with the consent of the shift supervisor, conduct it under the supervision of special personnel, make records, and resume the operation of the anti-misoperation device as soon as possible as required.
What is the function of preventing false locking in power system?
First, understand the types of locking, including electrical locking and mechanical locking. However, false locking often occurs in electrical locking.
For example, when the grounding of the load side of the line has been separated and the electrical signal has not been released, when the breaker gas or breaker is to be turned on, the electrical misoperation will lead to many problems. Is this misoperation ok? There are more than n examples, not to mention them one by one.
What kinds of electrical locking are common in substations?
There are two kinds of mechanical locking and electrical locking.