What you need to know about protecting the electrical network.
What you need to know about protecting the electrical network.
Operation of electrical networks
In production, industrial and other similar premises from operation of electrical networksthe main part of the work depends on, so it is important to follow the established rules to prevent dangerous situations. First of all, you should pay attention to the condition of the electrical insulation materials in the electrical wires. If there is dust or any contamination on the electrical insulation, this can cause a deterioration in its protective characteristics. When operating electrical networksoxidation and weakening of electrical contacts must not be allowed. This is fraught with high overheating of contacts and, in the best case, failure. It is necessary to monitor the electrical network and its components (for example, follow the rules for laying cables) in accordance with the established inspection schedule. The inspection schedule of electrical networks is approved by the chief power engineer of the enterprise. Of course, proper electrical wiring is also important for safety. In rooms with a normal environment, inspection of intra-shop electrical networks is usually carried out once every six months, and in rooms with an unfavorable environment (damp, with caustic vapors, etc.) — once every three months. During operation of electrical networksit is necessary to control their current load. Changes in electrical load occur for several reasons. If overload of electrical networks occurs for a long time, this will inevitably lead to undesirable overheating of electrical insulation. In case of constant overloads, it is necessary to take measures to unload the networks or strengthen them. When strengthening the electrical network, it is necessary to ensure that the currents in new wires and cables do not exceed the values established for them by the PUE. For the safe use of electrical equipment, the magnitude of the voltage supplied to electrical receivers is important. During hours of maximum electricity consumption, the voltage in the electrical networks decreases, and during hours of minimum consumption — it increases. You should also pay attention to the magnitude of fluctuations. If voltage fluctuations exceed the norms, it is necessary to use transformers that allow voltage regulation. In addition, if during general use of the electrical network any individual line was out of service for more than a month, during this time the line could have been damaged or damp. In such cases, the idle line is carefully inspected before being turned on and the condition of its insulation is checked, taking into account the data of the electrical wiring diagram.
Power grid load
According to the interstate standard GOST 13109-97 «Power quality standards in general-purpose power supply systems», the standards power grid loadcorrespond to the following indicators: the values of the steady-state voltage deviation at the terminals of the electric energy receivers are equal to ±5 and ±10% of the nominal voltage of the electric network; the permissible and maximum permissible values of frequency deviation are equal to ±0.2 and ±0.4 Hz, respectively. Any deviations in the parameters of the electric network loadfrom the values established by the standard, can cause malfunctions. These can be: a complete loss of voltage in the network, i.e. a network failure; long-term and short-term voltage drops and surges; high-voltage impulse interference; high-frequency noise; frequency deviation beyond the permissible values. The magnitude of the voltage in the network can be assessed using calibrated devices. To eliminate abnormal voltage, a stabilizer is used, which can be turned on directly in front of individual (or several) equipment.
Protection of the electrical network
Even if all the rules for safe operation are followed, one cannot be completely sure that no emergency situations will occur. Additional protection of the electrical networkwill not hurt in any case. Such functions are possessed by special devices that provoke automatic shutdown of devices in case of risk of emergency. Devices for protection of the electric network also work in the opposite direction — automatic switching on — when the normal state of voltage in the electric network returns. Protection must be connected to the power supply network that has protection against short-circuit currents and overloads. Protective devices include: network interference suppression filters — provide protection of electric networks, attenuating any signals in the range of 0.01-1000 MHz with an efficiency of at least 60 dB; noise generators for protection of the electric network — create a noise signal in the 220 V network, exceeding the level of signals from data collection devices or information signals; devices for protection against impulse overvoltage — devices of the lightning protection complex — to protect objects from lightning electricity, reducing the consequences of lightning striking the protected object or its secondary manifestations.