English Master Comes 2000 Word Translation

Optical fiber communications

Even though optical fibers are much smaller than pairs of wires, and silica (the most widely used material in fibers) is far more abundant than copper, The cost of fabricating rods from which fiber optics are drawn is several times greater than the cost of producing wires1 Furthermore, research suggests that this may have been on the case for some time.

However, fiber optic systems can be used to conduct more phone conversations at the same time than wire twins can carry them, so there is far less amplification of regeneration when there are many phone calls. To carry out between points, such as switching off ICE, fiber optic systems are economically attractive2. Therefore, the interdepartmental backbone will be the first to benefit from this new technology.

Competition is tougher, though, with existing high-capacity systems using coaxial transmission lines, waveguides, microwave radios and satellites. Larger fiber bandwidth, lower losses, and more reliable light sources make fiber optics more competitive in this sector.

The heart of an optical communication system is the one in which electrical signals are transmitted: a telephone, computer or cable TV. A light-emitting diode or laser converts these signals into light pulses, which travel along the glass fiber. On the receiving end, a light detector converts back an electrical signal.

This system offers significant advantages over traditional ones that rely heavily on electronic signals and copper wire. Inclusion means processing large amounts of information; a high-performance laser can generate up to 50 million light pulses per second. Therefore, it is possible to transmit the entire 30 volumes of the Encyclopedia Britannica in a tenth of a second. Because optical communications are not subject to electromagnetic interference, which can cause noise in copper cables, they deliver a clear signal despite nearby power lines or electricity. electric motor.

Copper wires, although they are insulated, can leak electrical signals and cause crosstalk in nearby wires. Not so with optical communications equipment. Fiberglass cable, furthermore, weighs only about one percent as much as copper wire to carry the same number of signals. In fact, a half-inch thick can carry as many signals as a copper wire as big as a man's arm. At the time, also because fiberglass carried light rather than electricity, there were no dangerous sparks in hazardous environments such as chemical plants or nuclear reactors.

Power Line Carrier Communication

Power Line Carrier (PLC) was first proposed in 1920. Since then. PLC technology has evolved into a mature and reliable communication technology, power transmission system, and today it is mainly used in relay protection, SCADA and voice data transmission systems.

The programmable controller uses a carrier frequency to transmit information than existing transmission lines. The carrier frequency for transmission line applications is usually 20 kHz and 300 kHz.Information is encoded on the carrier by using amplitude modulation (AM) of the single sided frequency band (SSB) and frequency shift keying (FSK). At the transmitting end, the modulated carrier is injected into a transmission line via a coupling capacitor and tuner. The modulated signal propagates down the transmission line to the receiving end. At the receiving end, coupling capacitors and tuners separate the PLC signal from the high-frequency supply voltage and a demodulator extracts the information-encoded signal. Trap lines at either end of a route, preventing carriers from traveling down unpopular paths.

The PLC does well with power transmission systems because they are electrically simple and have very few interruptions; typically, the assigned PLC frequency is used, from 5 kHz to 20 kHz. Generally frequencies less than 20 kHz are called distribution line carriers [DLC] and their use is permitted on a non-licensed, non-interference basis. For this reason, when we talk about PLC systems used in utility distribution systems, we call it DLC. Unfortunately, distribution lines are electrically complex because of the presence of numerous junctions, transformers and shunt capacitors. These severely attenuate the carrier frequency, making it difficult to reliably propagate a signal through the internal distribution system. In an attempt to correct this problem, operators distributed systems that utilized much lower frequencies than conventional transmission systems. These are closer to the power frequency and therefore less likely to be attenuated by the large amounts of parallel capacitance found on the distribution system.

Despite significant improvements, its less frequent use has not eliminated the associated problems of attenuation, the drug problem. In addition, signal "holes" are a serious problem. The hole occurs at a point where the DLC signal cancels the event reflecting the DLC signal. Signal reflections occur due to discontinuities such as transformers and line ends. When designing a DLC system, research is done to select a carrier frequency that has minimal difficulties and vulnerabilities. Future modifications to the distribution system may change the location of holes or create new ones, which may interfere with the DLC system. Special technology must be employed on the DLC system to correct this problem, just as special technology must be employed on the radio and telephone to correct this problem.

There is considerable debate about the ability of DLC to obtain past faults and outages in areas. The PLC on the transmission system can survive a single phase failure because the remaining phases provide additional paths to the carrier. In the event of a midpoint failure, the carrier can recouple phases from adjacent phases into the fault line far away from the fault. For the power distribution system, there are also many sections that are single-phase and cannot do this. Also, there are partial glitch conditions, such as a broken conductor, that will prevent drugs from passing through to the distribution system. Bypass route tuning equipment allows DLC signals to be sent close to reclosers and switches, making it possible to communicate in areas with outages.

Distribution line carriers have sufficient data rate capabilities for most distribution automation schemes. In today's technology, the data rate for a typical diamond-like system operating at a range of 5 to 20 kHz is 300 baud or less. The distribution line carrier has two bidirectional capabilities and is economically implemented for multiple functions, such as remote meter reading (RMR), as well as retrieval of load data from the point on the distribution network feeder.

DLC has the advantage of being used successfully, which is under utility regulation, reaching all points on the utility distribution system and requiring no catalytic cracking licenses. Despite these advantages, drug problems have limited data transfer rates. DLC can play an important role in distribution automation, but it is unlikely that alone it will be able to perform all of its necessary communications for distribution network automation.

Other wired communications

Telephone and TV cable are two types of wired communication; ,

The telephone is an effective and highly mature communication technology. It is a widely used tool for monitoring and relay protection. From a technical perspective, telephones are suitable for distribution automation. Telephone systems that provide high data rate capabilities have been built. Additionally, it is a bidirectional configuration that is easy to implement. Unfortunately, the cost of leasing phone lines is high, and utility bills have no control over the quality of phone lines and their communications. These disadvantages make telephonic distribution automation more attractive than it would be.1 In addition, there are points where line service is not available in some places, which is more expensive to local lines. Using dial-up telephone lines reduces costs compared to leased lines, but these are much slower due to "dial time" and will be very slow in performing functions such as fault isolation and restoring power that telephone lines have been used successfully Ground in distribution communications systems, but utilities continue to look for alternative systems that are under utility regulation and have no lease fees.

In areas where cable television systems can be operated, coaxial cables are mainly used as signal transmission paths. Signal amplifiers are placed in the system where necessary. Cable television systems have a vast bandwidth, and a large portion of it is idle. Distribution automation can utilize a very small portion of this available bandwidth. Most cable television systems are designed for one-way communication rather than two-way communication. Many utility customers do not subscribe to cable television. Cable TV suffers from the same disadvantages as telephones, these are considered to be under external control and may be subject to rental fees for their use.

Wireless communications

Radio has proven itself to be a viable communications technology for certain power distribution automation functions. Radio is a broad communications technology that requires little or no hard signaling and can be implemented in a two-way configuration. All radio systems have the ability to communicate to areas with power outages.

Radio communications technology is available in the following forms: AM Broadcast FM Broadcast VHF UHF Microwave Satellite

AM Broadcast -

Radio systems no longer There are commercially available distributed load controls that utilize AM radio stations to transmit information to a large number of load control units located in the distribution system1. This system is feasible by controlling the encoding load on the data being broadcast on the carrier. The information is encoded using phase modulation and is not detected by ordinary radio receivers, so the listener will not detect any degradation in the high quality of the radio waves, which are long enough to represent norizon better than VHF signals compared to VHF waves, and they meander around , and does not degrade tracking multipath distortion to the same extent as VHF signals. This makes the morning broadcast carrier suitable for communicating with large numbers of receivers in remote locations and the geographical diversity of such areas.

fmsca -

Another system using the radio station FM. The Secretary for Constitutional Affairs advocates a subsidiary communications mandate. Basically, the SCA signal is multiplexed into an FM broadcast mode, frequency modulated by a small group of carriers. Ordinary radios will not be aware of this system and are specially equipped with receivers that can decode the protocol information. FM SCA is one way out, and the communication system will be suitable for the same purpose as the AM live broadcast system. One disadvantage of FM protocols is that FM broadcast signals, due to their shorter wavelength, are more susceptible to multipath distortion, are shadowy and are limited to the line of sight. In congested or rough terrain, FM protocols are likely to provide poorer coverage than AM systems.

VHF Radio -

Radio waves with frequencies between 30 and 300 MHz are classified as VHF (Very High Frequency). Utilities considering VHF radio systems for distribution automation will find that there are only 3 available frequencies. Utilities enjoy one 300 watt, 3000 Hz bandwidth channel around 154 MHz and two 50 watt 3000 Hz channels are also allocated. Many utilities use these 3 channels for load control communications and may suffer from limited access and extensive coordination issues ranging from competing utility bills. A license, issued by the Fight Crime Commission, will be required for the utility to operate the system. VHF signals have limited range and are also susceptible to multipath distortion and tracking. As a caveat, this system must be taken into account; the cost may be prohibitive to achieve 100% coverage. Despite these shortcomings, VHF radios have been used in some unidirectional traffic load control systems and have had the ability to communicate to blackout areas, essentially under utility control and with low initial cost of ownership.

UHF Radio Waves -

Radio systems operating in the frequency range from 300 to 1,000 MHz are classified as UHF (Ultra High Frequency). Recently, the FCC approved applications for utility applications for frequencies ranging from 940 to 952 MHz. This opens up new possibilities to utilities that had not been considered for radio stations in the past, due to overcrowding and interference on existing VHF frequencies. Radio systems operating in the UHF range are more susceptible to atmospheric absorption, multipath distortion and shadowing effects than radio systems operating at lower frequencies. Nonetheless, radio systems in this range have proven themselves to be quite reliable and less susceptible to interference, providing more competitive services. Data rates up to band 9600 have been demonstrated on these new UHF channels. Additionally, the UHF antennas are smaller than the VHF antennas, due to the shorter wavelength. At this high frequency, wave propagation is essentially limited to the line of sight. In mountainous areas, UHF radio waves may not be a viable alternative.

Microwave

Microwave communication uses frequencies higher than 1 gigahertz. Microwaves are currently used by utilities for SCADA and relay protection applications. Using microwave communication systems, distribution automation is not possible except as the final link from the substation's RTU to the distributiondispatchcenter. This is due to the high cost and complexity of setting up microwave systems.

Microwave is not suitable for applications requiring multi-point communication. It is a point-to-point communication technology that has maintained its economic viability for two main reasons. It can replace a hardware signal channel, which has high bandwidth. For distribution automation, the data rate requirements and path lengths are so small compared to typical microwave applications, that the effective cost per channel becomes very high, making microwave unattractive for distribution automation unless it is Used in point-to-point high data rate configurations.

Satellite

Today, most satellite communications are made by means of a satellite in geosynchronous orbit. The satellite transponder has received the uplink signal and rebroadcast it on a different frequency. Because they fly at high altitudes, satellites provide broad uniform signal coverage. Communication can be through satellite, it is necessary to rent or own the transponder on the satellite and have the necessary uplink and downlink equipment. Microwave frequencies are commonly used for both uplink and downlink. Some utility companies successfully use satellites for monitoring, but due to the 1/4 second delay in early paths with geostationary satellites, they cannot be used for monitoring functions requiring very fast response times (such as relay protection). The use of satellites for power distribution automation is also under consideration.

Spread spectrum communications

Spread spectrum communications transmit many short messages through low-power transmitters without requiring a license. The frequency band transferred is 902 MHz to 928 MHz.

This solution also requires a relatively large amount of radio communication equipment, repeaters and RTU devices to transmit data over a wide area. Furthermore, combining data and voice is not possible, therefore, the infrastructure cannot use the benefits.