Arquivos electrical - Adolpho Eletricista

6 de dezembro de 2019
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Primary Distribution Network

Tags : Distribution Transformer Station Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul

Category : electrical

To address the issue of Primary Distribution Network, we first need to comment on Transformer Distribution Station, also known as Substation.

The Distribution Transformer Station aims to lower the Transmission or Subtransmission voltage to Distribution voltage levels.

As specified in the electrical construction project, we will know the output voltage of the Distribution Transformer Station

Distribution Transformer Station Output Voltage as well as Voltage Class are given below:

Class Output Phases

5 kV 3.8 kV ABC

15 kV 13.8 kV DEF

25 kV 24.5 kV GHI

35 kV 34.5 kV JKL

For design purposes, the 5 kV Voltage Class is no longer used as it requires high gauge cables because the lower the voltage the higher the electric current will be, and the cable gauge will determine the electric current.

We must also take into account the voltage value over the length of the circuit for the purpose of calculating voltage drop.

Distribution Transformer Station

Depending on the characteristics of the region, the Transformer Distribution Station may be aerial or underground.

According to the installed load and the forecast for the next years, the Voltage Class of the Distribution Transformer Station is determined.

The nomenclature of the primary circuits is composed of the acronym of the Distribution Transformer Station followed by the circuit number, knowing that the 5 kV Voltage Class is composed by two numbers, the 15, 25 and 35 kV by three numbers. 15 kV begins with number 1, 25 kV with 2, and 35 kV with 3.

Examples:

1 – A Distribution Transformer Station whose voltage is 5 kV, the circuit “0” will be XXX-00, the “1” will be XXX-01, “2” will be XXX-02, and so on.

2 – A Distribution Transformer Station whose voltage is 15 kV, the circuit “0” will be XXX-100, the “1” will be XXX-101, “2” will be XXX-102, and so on.

3 – A Distribution Transformer Station whose voltage is 25 kV, the circuit “0” will be XXX-200, the “1” will be XXX-201, “2” will be XXX-202, and so on.

4 – A Distribution Transformer Station whose voltage is 35 kV, the circuit “0” will be XXX-300, the “1” will be XXX-301, “2” will be XXX-302, and so on.

Pointing out that all primary distribution circuits ending with “0” or “1” are distress circuits and are only live (unloaded), and will only be used in emergency situations.

At the exit of the Distribution Transformer Station, in its extension and in the encounters with different primary circuits, we have the circuit switching knife keys, which can assume the state NO – Normally Open or NC – Normally Closed, according to the position in which is in the circuit.

Whenever the knife switch is in “vis-a-vis” function (meeting of two different primary circuits), it will be in the NO position.

At the exit of the Distribution Transformer Station and in the trunk (main circuit) of the primary, it will be in the NC position.

Normally Closed Knife Wrench – NC

Normally Open Knife Wrench – NO

We also find in the primary circuit automatic reclosers for protection and operation, voltage regulators, capacitor banks, and branch lines, where the fuse switches, also known as Matheus switch, are located for protection and operation of circuits.

Fuse Switch Set

In the knife, fuse knife and fuse keys we will find the identification plates of the primary circuit to which such equipment belongs. If it is a vis-a-vis knife wrench we will find on one side of the set the identification of one of the circuits, and on the opposite side the identification of the other.

Mains Identifications

Identifying from top to bottom we have:

A, B and C – Primary Phases

D – Neutral conductor

E – Fuse switch or Matheus switch

F – Fuse switch holder

G – Delta System Single Phase Transformer

H – Secondary distribution network

J – Secondary Connection Extension

K – Telephone network

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of the São Paulo – BR.

18 de novembro de 2019
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Opening and Closing Protection and Operation Switches

Tags : Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul Opening and Closing Protection and Operation Switches Switches

Category : electrical

The opening and closing of protective and maneuvering keys must follow some procedures contained in the Working Procedures Manual which will be discussed below.

All activities should be preceded by Preliminary Risk Analysis, use of Personal Protective Equipment and Collective Protection Equipment relevant to the task.

Note that there are identifying tags that show the Key and Primary Circuit number to which it belongs. The data must be checked and passed to the competent sector for conferencing and approval of the opening or closing of the device.

To open a key from the set, we must use a remote-opening switch stick and note that NEVER open the central key first, because if there is a problem with the key when opening it or opening an arcing we are in a situation of imminent accident. work of incalculable proportions, because we will be working between two energized phases.

All key opening operations must be performed with the LOAD BUSTER key opening device.

The first key to open is either side, depending on the wind direction and operator position relative to the key set.

The second key to be opened will be the middle one due to the previously verified wind direction; then the last key opens. Follow work procedures for signaling and temporary grounding for work.

To close the keys we must remove the temporary grounding, signs and make sure that all workers are away from the power grid, and ask the responsible sector for authorization to reenergize the circuit, because there may be other teams working in other parts of the circuit we don’t know.

Once authorized, we will proceed to lock the keys.

Again, the wind direction must be observed and the keys closed.

The first key to be closed should be the most difficult side, taking into account the wind direction and the position of the sun in relation to the operator’s eyes, due to the blindness of the views.

The center switch should NEVER be the last to be closed for the same reasons as opening.

The keys should be closed firmly and precisely, as if the keys hit and do not close, the operator should hold the key in a closed position until the circuit is de-energized at an earlier point, and this may take hours.

If you hit the key and it opens due to a failure in the closing operation, it will open a large electric arc, which can cause serious damage to the company’s assets and occupational accident involving the operator.

Return home the same way you left. No one is waiting for you amputated or in a coffin.

Work safely!

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of the São Paulo – BR.

3 de novembro de 2019
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Voltage Regulator – Medium Voltage

Tags : electrical Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul Voltage regulator

Category : electrical

Voltage regulators are equipment installed on long branches of primary circuits that feed low-density regions, particularly in suburban and rural areas where the natural voltage regulation of the circuit is impaired.
The regulators are single phase or three phase, which allows their use in single, two or three phase primary circuits.

It is programmed to start when the primary voltage is below or above the preset primary voltage limits (+ 10% or -10%).

Single-phase voltage regulators can be installed on single-phase lines or by forming two- or three-phase mounted banks in the primary networks. Assembly requires the identification of the source / load side.

The control of the voltage regulator is made by a voltage level and voltage drop compensation sensor of the considered circuit section that allows the automatic adjustment of the regulator position, raising or lowering, in the voltage regulator output, the voltage which receives at the input such that theoretically at a certain point of the primary circuit the voltage is constant.

Voltage regulator compensation is calculated so that the maximum output voltage of the first downstream installed transformer does not exceed the maximum operating voltage, and that the output voltage of the last transformer does not fall below the minimum operating voltage.

Definitions

Nominal voltage of a system or circuit

It is the nominal value assigned to the system or circuit of a given voltage class for the purpose of its convenient designation.

Nominal voltage refers to line voltage (phase-to-phase voltage), not phase to neutral voltage, and applies to all parts of the system or circuit.

Service voltage

It is the voltage to which the operating characteristics and performance of the equipment are referred.

Regulated Circuit

It is the circuit connected to the voltage regulator output and in which one wishes to control the voltage, phase relationship or both. The voltage can be kept constant at any point of the regulated circuit.

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

25 de outubro de 2019
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Electric Power System – EPS

Tags : Electric Power System electrical Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul

Category : electrical

EPS – Electric Power System is the set of all facilities and equipment for the generation, transmission and distribution of electricity up to and including measurement.

The generation is responsible for producing the electrical voltage.

The Electric Power Generating Plants can be:

Hydroelectric

Thermoelectric

Nuclear

Solar

Geothermal

Tidal Wave

Wind power

Biomass

After generation in AC, the voltage goes through a process of elevation to be transmitted at high voltage levels, due to lower losses and lower implementation cost of the transmission system, because the higher the voltage, the lower the electric current.

As the cable gauge determines the electric current and voltage drop, the higher the transmission voltage the smaller the cable gauge.

Transmission and subtransmission voltage values: 750; 500; 230; 138; 88; 69 kV.

The 69 and 88 kV voltages are considered subtransmission, ie the voltage values in a ETT – Transmission Transformer Station, to supply customers in subtransmission voltage.

When arriving at ETDs – Distribution Transformer Stations, also known as substations, the transmission voltage or subtransmission, depending on the supply voltage of the ETD, is lowered to primary distribution voltage values (34.5, 24.5 and 13, 8 kV). In some regions there is still a primary distribution voltage of 3.8 kV, but it is in extinction phase.

The primary distribution circuits in the Electric Power System are identified according to the voltage class and working voltage, as follows:

Class 5 kV – Working Voltage – 3.8 kV – Circuit ID beginning with “0”

Example: Circuit 03, 04, 05.

Class 15 kV – Working Voltage – 13.8 kV – Circuit ID beginning with “1”

Example: Circuit 103, 104, 105.

Class 25 kV – Working Voltage – 24.5 kV – Circuit ID beginning with “2”

Example: Circuit 203, 204, 205.

Class 35 kV – Working Voltage – 34.5 kV – Circuit ID beginning with “3”

Example: Circuit: 303, 304, 305.

All ETDs have a name and an acronym. In the case of Capuava ETD, acronym CAP. ETD Santo André, acronym SND, and the nomenclature of the primary circuits will be:

SND – 03 – SND – 04 – SND – 05, because the primary distribution voltage of this ETD is 3.8 kV.
CAP – 103 – CAP – 104 – CAP – 105, because the primary distribution voltage of this ETD is 13.8 kV, and so on.
Primary distribution circuits with end ’00’ and ’01’ are distress circuits and are not used to distribute voltage to urban centers like the others. They are only in ‘voltage’, unloaded. If a problem occurs in any other circuit, such as a transformer failure, for example, the relief circuit will assume the load of the failed circuit through knife-wrench maneuvers.

Upon arriving at the electricity consumption centers, the primary distribution voltage may serve industrial customers and large Medium Voltage customers through the primary cabin, a contract to be entered into with the electricity concessionaire through electrical projects and other documentation.

To serve low voltage customers – BT, primary distribution voltage values should be lowered to secondary distribution voltage values and delivered to the customer input standard.

The utility is responsible for supplying the voltage value in accordance with the Norms and Standards to the customer input standard circuit breaker.

Responsibility for the construction and maintenance of the input standard is the responsibility of the customer, as well as the conservation of the watt hour meter that will be his responsibility. In case of misuse or vandalism, the customer will be responsible for the consequences.

Responsibility for periodic maintenance of the watt hour meter and repair in the event of damage due to wear of the equipment lies with the utility.

The supply voltage values in the delta and star system can be checked in the Delta System and Star System articles.

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

21 de outubro de 2019
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Active, Reactive, Apparent, Capacitive and Inductive powers.

Tags : active powers apparent power capacitive power Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul inductive power powers reactive power

Category : electrical

A brief comparison of active, reactive, apparent, capacitive, and inductive powers in order to define them.

Apparent Power: is the power acquired by the concessionaires of the generators.

Active Power: This is the power delivered to customers that generates work.

Reactive Power: is the power generated during the operation of certain equipment that generates high power factor and, when returned to the Electric Power System, impair the distribution and transmission networks of electricity, because the current is delayed in relation to the tension.

Capacitive Power: It is the power that, by having the current ahead of the voltage, compensates the Reactive Power, which has the delayed current.

Inductive Power: It is generated by purely resistive equipment, where the power factor is 1 and does not harm the SEP.

We can make a power analogy with a beer mug, where:

*kVA is the apparent power that utilities buy from generators, which equals the full draft beer mug we buy in a beer house;

*kW is the active power supplied to customers that actually generates work, ie the net portion of the beer mug we actually consume;

*kVAr is the reactive power that is wasted, ie the foam that is not consumed.

In order to reduce the amount of foam in the cup (losses), the attendant passes the ruler on the edge of the cup (power factor control), which is equivalent to installing a Capacitor Bank in the customer’s.

The power supplied to customers by the Dealers is active.

Resistive equipment generates inductive power and its power factor is 1, which does not harm the SEP.

Equipment such as motors, transformers and reactors generate Reactive Power and, consequently, influence the power factor, which is the relation between Apparent Power and Active Power.

The ideal power factor is 1, but due to reactive power, we will never have this value in a power grid.

To minimize and control damage to the Electric Power System, the National Electric Energy Agency (BR) has established that the power factor cannot exceed 0.92 in Brazil.

If the customer exceeds this value, measured by the concessionaire’s watt hour meter, a fine defined in a contract with the concessionaire will be applied upon request for the connection of electricity.

This fine is charged to the electricity bill and passed on to the National Electricity Agency (BR).

If the customer deactivates machines, suspends activities or goes on a collective vacation, the capacitor bank must be resized or deactivated, as the excess of Capacitive Power also harms the Electric Power System and increases the value of Factor and Power.

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

19 de outubro de 2019
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Learn What is Automatic Circuit Reclosers – ACRs and How It Works

Tags : Automatic Circuit Recloser Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista Zona Sul

Category : electrical

The Automatic Circuit Recloser – ACR, is an automated switching equipment installed in electrical distribution networks, usually in 13.8, 27 and 36 kV primary circuits.

Automatic Recloser — Automatic Circuit Recloser in Poste

They are predominantly located in the primary distribution network, however, to re-establish power supply interruptions more efficiently and quickly, they are also found in Distribution Transformer Stations (DTSs), also known as substations, operating in coordination with an automatic disconnect switch. with a circuit breaker.

Automatic Circuit Reclosers – ACRs in DTS

The Automatic Circuit Recloser has two basic functions in the distribution system: reliability and overcurrent protection. They are often used to increase the reliability of the electrical power distribution system.

It is a cost-effective solution for disconnecting power grids, and is often used in locations where coordination with other protective and maneuvering equipment is difficult. It is suitable for use in medium voltage overhead distribution networks in coordination with automatic recloser circuit protection. Its operating principle is based on automatic detection of grid failure, interrupting the electrical circuit temporarily.

After a pre-configured period, the ACR will automatically restore power to the mains, checking if the circuit failure still persists. If it persists, it will shut down and after a certain time will restart again.

It can be programmed for two quick reclosing attempts – from 10 to 15 seconds each operation and two delayed attempts – from 20 to 30 seconds, or one quick and three delayed attempts, or according to the need of the electrical circuit where it will be installed. If the fault has been rectified after the first operation, the ACR will remain on and the electrical circuit will be restored, without the need for professional intervention; otherwise, it will shut down and after the set time will attempt to restart again. The maximum number of circuit reclosing attempts is four operations. If reclosing is unsuccessful, a team of professionals should attend the site to rectify the fault and restart the equipment.

They are usually installed in wooded areas,

where the incidence of branches in the distribution network is large, which causes the circuit to be disconnected. Since the time that the branch stays on the net is usually short, probably on the first attempt of reclosing the branch has already left the network and the circuit is reestablished.

Another application of the automatic recloser is to block the reclosing of the electrical circuit. When live (energized) work crews will work beyond ACRS, the lockout function is used because if an accident occurs while working, it will shut down and will not restart again.

After the services are executed, the ACR is removed from the blocking condition. It can also be used to disconnect the electrical circuit for dead line maintenance.

ACR shutdown, reclosing and blocking operations can be performed by specific equipment for maneuvering by trained professionals, or by automation (remote operation).

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

8 de maio de 2019
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Losses in the Electric Power System

Tags : distribution Electric Power System electrical Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul Generation LOSSES Transmission

Category : electrical

The Electrical Power System consists of generation, transmission and distribution. Losses in the Electric Power System refer to the generated electric energy that passes through transmission lines and distribution networks, but which is not commercialized, either for technical or commercial reasons.

The transmission of energy, whether in transmission or distribution, inevitably results in technical losses related to the transformation of electrical energy into thermal energy in conductors (joule effect), losses in transformer cores, dielectric losses, etc.

Non-technical or commercial losses stem mainly from theft (clandestine connection, direct network diversion) or energy fraud (tampering in measurement), popularly known as “cats”, metering and billing errors.

Losses in the Electric Power System are controlled through the automation of the electric system and power factor control (PF), according to the ANEEL Ordinance, which establishes PF = 0.92. This control against the big consumers is done with great seriousness and those who escape the limit of 0.92 will bear a heavy fine.

Another way to control losses is by using peak and intermediate rush hour rates. Many customers chose to use the Generator Group that was inoperative at these times, putting it to operate, in order to reduce the consumption of electricity at these times. The amount that is spent on diesel is much lower than with electricity tariffs and fines.

End Time

This schedule is composed of a period of three consecutive hours that is adopted between 5:00 pm and 10:00 pm, including holidays, except Saturdays and Sundays. These times can vary from concessionaire to concessionaire, according to the region in which it is established.

Intermediate Hours

It is the period comprised of an hour before and an hour after the rush hour.

Off Time

It’s the remaining 19 hours of the day.

The white tariff for residential customers is in force, which is the incentive for not using high power equipment, such as shower, electric faucet and iron, during peak and intermediate hours.

The white tariff is a new tariff option that signals to consumers the variation of the energy value according to the day and time of consumption. It will be offered to consumer units that are serviced at low voltage (127, 220, 380 or 440 volts, denominated group B) and to those belonging to group A that opts for the low voltage tariff. The measure was approved in a public meeting of the Board of Directors of ANEEL.

The star system transformers projects, as mandated by ANEEL, also contribute to the reduction of losses because it is a more balanced and reliable system than the delta system. The goal is to eliminate, over time, the delta distribution system.

Inspections with thermovision to check and subsequently eliminate hot spots – current leakage – occurring in compromised connections, equipment or insulators are constant practices, as well as load balancing between primary phases.

The construction of new DTEs and new circuit designs, including changing the distribution voltage class from 5 kv to 15 kv or 25 kv, according to the region, are prime factors to reduce losses in the Electric Power System, since the higher the voltage the lower the current and, consequently, the lower the losses.

Moving to compact primary network – space cable – is also a determining factor for loss reduction. The Department of Distributed Engineering analyzes and controls all primary circuits, and when necessary intercedes for its improvement.

Technical Losses in Distribution

The distribution system is divided according to the network segments (high, medium and low voltage), transformers, connection extensions and meters. Specific models are then applied for each of these segments, using simplified information of existing networks and equipment, such as length and gauge of conductors, power of transformers and power supplied to consumer units. Based on this information, it is estimated the percentage of efficient technical losses related to the energy injected into the network.

Non-technical losses

The non-technical losses are calculated by the difference between total losses and technical losses. The regulatory values of non-technical losses are calculated by ANEEL by a methodology for comparing the performance of distributors, observing efficiency criteria and the socioeconomic characteristics of concession areas .

Sources: ANEEL – National Electric Energy Agency

ENEL Distribuição

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of the São Paulo – BR.

8 de maio de 2019
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GTD – Generation, Transmission and Distribution of Electric Energy

Tags : distribution Electric Energy electrical Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul Generation Transmission

Category : electrical

When we are dealing with GTD – Generation, Transmission and Distribution of Electric Energy, we refer to the SEP – Electrical Power System, which is defined by “all the materials and equipment necessary for the Generation, Transmission and Distribution of Electric Energy to the final consumer, including”.

The electric power is generated in the Power Plants, which can be: Hydroelectric, Thermoelectric, Nuclear, Solar, Wind, Geothermal and Tidal Power.

After generation, the voltage must be raised to transmission voltage levels, which is done in an Transformer Transmission Station, located next to the Generating Plant. It is a Voltage Lifting Substation.
The voltage is raised to 138 kV, 235 kV, 440 kV, 750 kV at the 60 hertz (AC) frequency, and there are some transmission networks operating at 1 MV on an experimental basis.
Some transmission networks work in DC until certain point of the circuit, being converted back to AC.

HVDC systems are an alternative for the transmission of large blocks of energy (over 1500 MW) over long distances (over 1000 km).

In the 1950s, the transmission voltage was 50 kV, then it was changed to 69 kV and some years later to 88 kV. Today these voltage values are considered subtransmission voltage.

After the Transmission, there is a Transformer Transformer Station, where the voltage is transformed into subtransmission values to feed the Transformer Distribution Stations and Substations of large industries.

The reason for increasing the value of the transmission voltage over the years was the increase in the demand for electric power, caused by the population increase, industrial and business growth and the range of consumer electronics devices that appeared in the consumer market, with increasing powers high.

As an example we have the electric shower, which migrated from 3000 W to 4500 W, 5600 W, 6800 W and 7800 W. Aluminum Cable for Transmission When we talk about increased demand, we refer to an increase in electric current, which causes overload in the Electrical System of Power and Loss, requiring the increase of the working voltage to lower the current, as they are inversely proportional in the SEP.

Another determining factor for raising the transmission voltage is that it is possible to reduce the gauge of the electric conductors, as the current values are lowered; we can not forget that the calculation of voltage drop is also a preponderant factor for the calculation of the gauge of the conductor to be used.

Upon reaching urban centers, electricity must be lowered to levels of distribution to be delivered to customers.

The whole process of distribution network operation is found in the articles Primary Distribution Network, Distribution Transformer Station, Underground Distribution Network among others in this site.

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo- SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

8 de maio de 2019
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Know the Star System of Distribution of Electric Energy

Tags : electrical Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul energy star system

Category : electrical

The Star System is composed of a three-phase transformer powered by the three phases of the primary circuit of electric energy distribution.

The primary bushings H1, H2 and H3 are fed by the 3 primary phases, protected by fuse switches (Matheus) and links specified according to the power of the transformer.

In the secondary output bushings X0, X1, X2 and X3, we will obtain the output voltages, as shown below:

The system is powered at 13.8 kV, since the phases are D, E and F, subject discussed in the article on Delta System.

The bushing X0 corresponds to the NEUTRAL of the star system, X1 to phase A, X2 phase B and X3 phase C.

The nominal voltages between Neutral and Phase A, Neutral and Phase B, Neutral and Phase C are equal to 127 V and nominal line voltages equal to 220 V (127/220 V system).

Phases A, B and C are better known in the industry for R, S, and T.

Schematic of a star transformer In the star system 220/380 V the nominal voltage between Neutral and Phase is 220 V, and the nominal line voltage is 380 V.

The expression used for voltage calculation in the three-phase system is as follows:

Where: VFN – neutral phase voltage

VFF – phase phase voltage or line voltage

V3 = 1.73 (approximate value, since it is periodic tithe)

According to the star formed by the 3 secondary coils (figure above), we notice that the phase angle between Phases A, B and C is 120º, which keeps the voltages out of phase as shown below:

Three Phase Voltage Diffusion Chart Author’s Note: RMS voltage, from the English Root Mean Square or Effective Value are the line or phase voltages.

Analogy between Star System and Delta System

In the Star System, because of the balanced voltages, we have been able to load loads much higher than the Delta System, which presents unbalanced voltages.

Due to the imbalance between the secondary voltages, the Delta System generates a very large load unbalance in the SEP – Electrical Power System, damaging it, whereas in the Star System, because of the balanced voltages, we can balance the loads with greater ease, keeping the SEP more stable and generating a smaller number of maintenance in the circuits of distribution, transmission and the generation of electric energy.

Conclusion

The Star System is infinitely better than the Delta System in all respects.

short Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician Residential, Commercial, and Industrial

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

5 de maio de 2019
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Frequently Asked Questions about the Delta Distribution System

Tags : delta system electricity Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista Zona Sul star system

Category : electrical

Some frequent questions from site readers and professionals in the area.

Do three-phase equipment manufactured for the Star System work on the Delta System?
Both motors and resistors operate normally in the Delta System. Only the motor connections must be performed by a qualified professional to avoid damaging the motor.

Is the Delta System in practice the same as the Triangle?
Delta system and triangle is the same thing. It is called a triangle because the representation of the Greek letter delta is a triangle.

One of the differences between the Delta Three Phase System is that the fourth phase (S phase) has higher voltage than the neutral?
Yes. The nominal voltage of the fourth phase (phase S) with respect to the neutral is 200V, while in the star system the phase voltages are balanced (127V between phase and neutral).

I purchased a machine for Star System 220V three phase. When I explained that the three-phase Delta System is here, the supplier did not know how to inform, because it does not know the System.
Several machines manufactured for the Star System are installed in the Delta System, however it is necessary to make the necessary conversions of connections by a qualified professional. There are some connections that differentiate the Delta System from the Star System. It is necessary to check the type of connection of the motor, which can be connected in various ways, according to the wiring diagrams stamped on the nameplate.

Can the same three-phase machine that binds to the Star System be connected to the Delta System?
If the machine came from the factory to work on star it is necessary to adapt the connections to delta system. The operating system of the machine is powered at 127 or 220 V, so it is indifferent to be delta or star to the HMI and CLP. Who works in the three phase is only the motor and some types of resistors that can be connected in delta.

The neutral of the Delta and Star System is the same, as well as the secondary and primary distribution network. Every neutral grid is interconnected and grounded at specific points.

As more questions arise from readers, professionals and customers, will be added in this article as a review.

CURTA Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – BR!

I attend in São Paulo, Greater São Paulo and South Zone of the São Paulo – BR.

5 de maio de 2019
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Know the Delta System of Electric Energy Distribution

Tags : delta system Eletricista em Santo Amaro Eletricista em São Paulo Eletricista na Zona Sul de São Paulo Eletricista no Capão Redondo Eletricista Zona Sul star system

Category : electrical

Delta (Triangle) System transformers are single phase – powered by only one primary phase.
The nominal voltage between phase / neutral is 115 V.
The nominal line voltage – phase / phase – is 230 V.
The calculation for line voltage in the Delta System is:
VL = 2. VFN
Where: VL = line voltage
VFN = phase / neutral voltage
In the figure below, we have the example of a delta system transformer, powered at 13.8 kV.
How to know the supply voltage? Simple: The primary phase of the traction power supply is phase D.
Remembering
Class 5 kV – Working voltage – 3.8 kV – Phases A, B, C.
Class 15 kV – Working voltage – 13.8 kV – Phases D, E, F.
Class 25 kV – Working Voltage – 24.5 kV – Phases G, H, I.
Class 35 kV – Working voltage – 34.5 kV – Phases J, K, L.
According to the letter that defines the stage in which the equipment is connected, we know the Voltage Class and the Voltage of Power. According to the scheme below, we find that the primary bushing H1 is connected in phase D and the bushing H2 is grounded to generate potential difference (ddp) between the ends of the primary coil in order to generate magnetic field and lower the voltage across of the secondary coil.
A fuse switch (Matheus) must always be installed between the phase and the bushing H1 of the transformer.
The capacity of the fuse link will be determined according to the power

Delta Light System

The secondary coil has three tapping points, x1, x2 and x3, where x1 and x3 are the ends of the coil and x2 is the center tap, from which the neutral is generated – zero potential under ideal conditions.
It is practically impossible to keep the neutral conductor at potential ‘zero’ due to the huge unbalance of loads existing in the Electric Power System.
GRADES:
1 – All the neutral grid of the electric utilities are interconnected and grounded at certain points, including in the Transformer Distribution Stations (DTEs), also known as Substations, regardless of whether the System is Delta or Star.
2 – The Neutral of the primary distribution circuit is the same as the secondary circuit. There are no two Neutral (primary and secondary) conductors, only one, called the General Neutral.
The entire neutral grid is grounded in order to keep the neutral as close as possible to the zero potential.
The Delta Light System is efficient only for residences, businesses and small businesses that do not need the fourth phase (fourth because the neutral is considered as phase) to work. When the client needs the fourth phase, with the largest motor up to 5 CV, the Delta ‘opens’, as shown below.

Open Delta System

In order to ‘open the Delta’, another single-phase transformer – F1 – but connected in another primary phase – phase E – is added, except that x2 will remain open, and the connection scheme of x1 of the LIGHT must be obeyed the x3 of FORCE, or x3 of the LIGHT with the x1 of FORCE.

If there is an inverted connection, x1 with x1 and x3 with x3, the motors will turn upside down and will be damaged.

The neutral phase and line voltage voltages remain the same, 115/230 V, but the nominal voltage of the fourth phase with the neutral will be 190 V, and phase voltages with 4th phase will be 230 V nominal.

The 4th phase ONLY must be used to power three-phase motors and loads, NEVER to supply single- or two-phase loads, due to the difference in nominal voltage and phase angle and phase 4 voltage phase angle values.

If this happens, there will be equipment burning.

Closed Delta System

The most frequent question is: "how do you get to the value of 200 V between neutral and 4th phase?" 
Analyzing the above scheme, we can verify that we have 1/2 coil of the LIGHT transformer (from x2 to x1) plus 1 entire coil of FORCE 1 (from x3 to x1), totaling 1 coil and 1/2, which generates 200 V between NEUTRO and phase 4.
The FORCE traction must always be of less power than the light traction, or at the maximum of the same power. 
When the customer has to drive motors above 5 hp, the Delta must be 'closed', obtaining greater power from the transformer bank.

 
In order to 'close' the Delta, one more single-phase F2 is added, fed by another primary phase (F).
The nominal voltages of neutral phase, line and phase 4 do not change. 
The connection diagram should be carefully observed: if x1 of F1 is connected in the 4th phase, x3 of F2 must also be connected to 4th phase, and x1 of F2 connected to x3 of LIGHT. 
If the x3 of the F1 is connected in the 4th phase, the x1 of F2 must be connected to the 4th phase and the x3 of the F2 connected to the x1 of the LIGHT. If there is an error in the connections, x3 of F1 with x3 of F2 and x1 of F2 connected with x1 of the LIGHT will cause a short circuit between phases, and when it is connected the Closed Delta will burst the protective fuse links of the three phases of the bank of trafos and the three circuit protection fuses. If the circuit is protected by Auto or Sectionalizer, they will operate and disconnect the primary circuit. If there is no protection in the circuit before the traffic bank, you will turn off the primary circuit in the Transformer Distribution Station (substation). 
The forces of FORCE must be of equal and inferior power or at most equal to the trafo of LIGHT. 
Who will determine the power of the trafos to be installed will be the technical department of the concessionaire after analysis of the electrical design and relation of loads presented by the customer when request of connection, addition of load or modification.

Delta System transformers are connected in the same primary phase. In these cases, there are two LIGHT transformers connected in parallel and their powers add up. This procedure is used when a higher power bank is needed in the LIGHT and there are no commercially available trains at this power.

Example: A bank of 200 kVA LIGHTs is required. Two parallel 100 kVA trains are installed to achieve 200 kVA.

The Delta trafets in the distribution networks are 5, 10, 15, 25, 37.5, 50, 75 and 100 kVA, but currently only 10, 25, 50 and 100 kVA are commercially available.

According to the Ordinance of ANEEL – National Agency of Electric Energy – Brazil, from the 90’s onwards, it was prohibited to design Transformer Distribution Stations of the Delta System, allowing only maintenance in existing ones. The Transformer Distribution Stations designed as of the force of the Ordinance shall be of the Estrela System, in order to improve the load balancing of the primary distribution circuits and the transmission circuits.

Advantages of the Delta System

The only advantage of the Delta System is the cost of implementing the system, because with only one primary phase secondary voltage is obtained to serve residential, commercial and business customers that do not need a three-phase network.

At a much lower cost than the Star System, the goal is achieved. Disadvantages of the Delta System The Delta System generates a very large load unbalance in the Electric Power System – SEP, requiring constant electrical current measurements of the primary distribution and transmission phases, often being necessary to transfer transformers from one phase to another in order to balance the loads of circuits.

SHORT Adolpho Eletricista

Adolpho Eletricista – Your Electrician in São Paulo – SP!

Electrician residential, real estate, commercial and industrial.

I attend in São Paulo, Greater São Paulo and South Zone of São Paulo – BR.

Category Archives: electrical

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Primary Distribution Network

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Opening and Closing Protection and Operation Switches

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Voltage Regulator – Medium Voltage

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Electric Power System – EPS

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Active, Reactive, Apparent, Capacitive and Inductive powers.

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Learn What is Automatic Circuit Reclosers – ACRs and How It Works

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Losses in the Electric Power System

End Time

Intermediate Hours

Off Time

Technical Losses in Distribution

Non-technical losses

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GTD – Generation, Transmission and Distribution of Electric Energy

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Know the Star System of Distribution of Electric Energy

Analogy between Star System and Delta System

Conclusion

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Frequently Asked Questions about the Delta Distribution System

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Know the Delta System of Electric Energy Distribution

Delta Light System

Closed Delta System

Advantages of the Delta System

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