Additional charges to businesses to keep the lights on during load-shedding

Eskom chairman and acting CEO Jabu Mabuza said they are not failing to resolve the country’s energy crisis, despite having to implement stage 6 load-shedding.

Many South African landlords are introducing additional charges to keep the lights on during load-shedding because of the unprecedented number of outages this year.

To date, many office parks provided backup generator power to their tenants as a free perk, but this is changing because of the increase in load-shedding.

One landlord highlighted that they had no load-shedding in 2016 and 2017, and only 19 hours of outages in 2018.

In December 2019 alone, they suffered 25 hours of outages, and from 1 January 2020 to 9 February 2020 they already had 35 hours of load shedding.

This increase in load-shedding means that generators have to be serviced and repaired more regularly, which increases the cost of offering emergency backup power.

To compensate for the increased costs, office parks are now starting to charge a monthly generator standby fee and usage-based charged for providing power.

Paying to keep the lights on

The monthly generator standby fee differs significantly from one office park to the next as it is based on factors like the number of tenants and the power needed.

Accounts seen by MyBroadband suggest a typical generator standby fee of between R100 and R200 per month.

This standby fee typically includes one or two operating hours per month, after which tenants will be charged based on energy consumption and the duration of running the generator.

The table below provides an overview of the generator charges from a prominent business park.

Loadshedding Charges
Business sizePower consumptionPrice
Small businessUnder 1,000kWh per monthR10 per hour
Medium business1,000 to 5,000 kWh per monthR40 per hour
Medium to large business10,000 to 40,000kWhR400 per hour
Large businessOver 50,000kWh per monthR1200 per hour

Big additional cost to a business

In a month with 25 hours of load shedding, like December 2019, the additional cost to a medium-to-large business will be around R10,000 per month.

A medium-sized business can expect to pay an additional R1,000 a month, with a large business being charged R30,000 extra per month.

With a struggling economy and a depressed business market, these additional charges will be hard to stomach for many businesses

Speaking to ENCA, Mabuza said the situation Eskom currently finds itself in is due to the poor reliability of power plants and a lack of maintenance.

He said Eskom is currently ensuring that it is implementing controlled load-shedding, and that stage 6 load-shedding is not a calamity because it is controlled.

He added that this controlled load-shedding is necessary to protect the electricity grid against total collapse.

Pravin Gordhan blames the previous administration

Public Enterprises Minister Pravin Gordhan blamed “what happened in the past ten years” for the return of load-shedding in South Africa.

Load-shedding returned after Gordhan took over the public enterprises portfolio, and many people are pointing fingers at his leadership for the return of blackouts.

Gordhan, however, dismissed this accusation, saying Eskom is trying to recover from the problems which were created over the past decade.

“There was no long-term maintenance done and we repeated that many times,” Gordhan said.

He said many of the current critics are the ones who were responsible for the problems which Eskom is currently facing.

Getting back to normality

Gordhan said their immediate aim is to get back to normality without any load-shedding.

After this is achieved, he said they will ask a lot of questions related to getting generation capacity online again and ensuring Eskom improves its level of maintenance.

He said they will focus on getting better-quality repair work done on some of the boiler tube leaks and other technical problems.

Article originally from Mybroadband

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We are not failing – Eskom chairman

Eskom chairman and acting CEO Jabu Mabuza said they are not failing to resolve the country’s energy crisis, despite having to implement stage 6 load-shedding.

Speaking to ENCA, Mabuza said the situation Eskom currently finds itself in is due to the poor reliability of power plants and a lack of maintenance.

He said Eskom is currently ensuring that it is implementing controlled load-shedding, and that stage 6 load-shedding is not a calamity because it is controlled.

He added that this controlled load-shedding is necessary to protect the electricity grid against total collapse.

Pravin Gordhan blames the previous administration

Public Enterprises Minister Pravin Gordhan blamed “what happened in the past ten years” for the return of load-shedding in South Africa.

Load-shedding returned after Gordhan took over the public enterprises portfolio, and many people are pointing fingers at his leadership for the return of blackouts.

Gordhan, however, dismissed this accusation, saying Eskom is trying to recover from the problems which were created over the past decade.

“There was no long-term maintenance done and we repeated that many times,” Gordhan said.

He said many of the current critics are the ones who were responsible for the problems which Eskom is currently facing.

Getting back to normality

Gordhan said their immediate aim is to get back to normality without any load-shedding.

After this is achieved, he said they will ask a lot of questions related to getting generation capacity online again and ensuring Eskom improves its level of maintenance.

He said they will focus on getting better-quality repair work done on some of the boiler tube leaks and other technical problems.

Article originally from Mybroadband

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Eskom wants to hike electricity prices even higher

Eskom wants R27.2 billion to be added to power tariffs to account for the amount under-recovered in the 2018/19 period, the City Press reports.

National energy regulator Nersa has published Eskom’s latest application for public comment, in which Eskom suggests that this increase be implemented over the next two years.

It is unlikely that Nersa will come to a decision in time to implement Eskom’s requested increase to tariffs before the 2020 tariff increase takes place, however.

If Nersa was to grant Eskom the full R27.2 billion for 2021, electricity tariffs for the year would increase by 11.38% rather than the currently expected 5.01%.

The application is made in terms of the regulatory clearing account (RCA), which allows Eskom to retrospectively mitigate risk that assumptions regarding tariffs may be incorrect.

As part of the application, Nersa will compare Eskom’s spending in the 2018/19 period to the tariff that it was awarded for this period.

According to Eskom, it was awarded R86 billion in this period, while its costs totaled R99.4 billion.

Eskom’s claims

Eskom said that its increased expenditure is due to several miscalculations.

The national power utility wants an additional R5.4 billion to be allocated as a result of lower-than-predicted sales.

This does not include reduced sales as a result of load-shedding, Eskom said, which cost Eskom R762 million over the course of 418.5 hours of power cuts.

Eskom said that sales to municipalities, mines, and households were particularly lower than expected.

The power provider also said it spent R16.7 million more on the purchase of coal than was predicted.

Eskom criticised Nersa for allocating less to coal purchases in the 2018/19 period than it did for the previous year. This figure was also nearly R10 billion less than what Eskom applied for.

The power provider said that Nersa did not account for the cost of existing coal contracts which Eskom had already committed to; instead, the regulator supposedly based the figure on an index that ignored Eskom’s procurement policy as well as developments in the mining sector.

Eskom also wants R4.8 billion for various other costs including depreciation and operations.

Load-shedding returns

Eskom has re-introduced load-shedding over the past week, implementing stage 2 load-shedding on Thursday before escalating to stage 4 on Friday.

The national power utility attributed these power outages to a variety of reasons, including its generating plant operating at low levels of reliability, unplanned breakdowns totalling in excess of 12,500MW, and wet coal.

Eskom expects stage 2 load-shedding to take place on Sunday between 09:00 and 23:00.

Article originally from Mybroadband

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Eskom load-shedding escalated to stage 4

Eskom will initiate stage 4 load-shedding from 14:00 on Friday.

Eskom said on Twitter that available capacity has gone down and demand has increased.

“The increase in the load-shedding stage is intended, among other things, to cater for further unplanned trips and to create capacity to replenish water reserves for our pumped storage schemes.”

For now, the prognosis is that Eskom will implement stage 4 load shedding between 14:00 and 06:00 tomorrow.

The escalation to stage 4 load-shedding has also been reflected on popular load-shedding app EskomSePush.

Load-shedding returns

The power utility previously initiated stage 2 load-shedding from 16:00 on Thursday, which concluded on Friday at 05:00.

It also announced earlier on Friday morning that Stage 2 load-shedding would restart at 09:00 and would continue until 06:00 on Saturday.

“As the electricity system continues to remain under severe pressure with unplanned breakdowns remaining above 12,500MW, Stage 2 load-shedding will regrettably be implemented from 09:00 until 06:00 tomorrow morning,” Eskom said.

The power utility said it was using diesel at its open-cycle gas turbine to supplement its capacity and limit the amount of load-shedding taking place.

Eskom added that its technical teams would continue to work around the clock to return additional power units to the grid, but incessant rain was also causing coal-handling problems at numerous power plants.

“This could further impact supply as the rainy weather persists. While not expected or planned, further deterioration of plant performance or the emergence of other risks may necessitate invoking further stages of load-shedding.”

Eskom confirmed that the rain did result in coal-handling issues, which contributed towards the load-shedding escalation.

“If the wet persists, we are likely to implement load-shedding throughout the weekend,” Eskom said.

Article originally from Mybroadband

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Eskom: Loadshedding a last resort to avoid total blackout

Eskom said in a statement on Sunday morning that it wants to remind South Africans that loadshedding is a last resort to protect the power system from a total collapse or blackout.
Although the power system still remains constrained and vulnerable, Eskom does not expect to implement loadshedding on Sunday.

It cautioned, however, that any change in the situation could indeed lead to loadshedding at short notice. For example, additional unplanned breakdowns or the unavailability of diesel for our open cycle gas turbines or water levels at pumped storage schemes, could result in loadshedding at short notice.

This happened on Thursday evening, for example, when Eskom had to suddenly implement stage 2 loadshedding from 22:00 until 05:00 on Friday morning. Since then no loadshedding needed to be implemented.

According to Eskom, some progress has been made in replenishing diesel for open cycle gas turbines and improving water levels for pumped storage schemes. However, given that unplanned breakdowns are above 10 500 MW the probability of loadshedding remains, but will only be implemented if absolutely necessary.

The Emergency Response Command Centre continues to monitor the system and will be in a position to give a prognosis, for the week ahead, during the course of tomorrow.

Fin24 reported earlier that, after some of Eskom’s generating units failed over last weekend, power supply was running dangerously low by Wednesday morning.

Unplanned outages above 9 500 MW mean Eskom has to resort to emergency power generation by using open cycle gas turbines and pumped-storage hydroelectric plants.

These are very expensive ways of generating power, particularly the gas turbines, which require large quantities of diesel.

Article originally from Fin24

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Medupi: the unstable lifeline to Eskom and SA – Yelland

Last week’s loadshedding was another reminder of how fragile the Medupi power station is. With Kusile, these power stations were supposed to be the flagships of South Africa’s power generation but instead of that; it has become as Bloomberg put it “textbook studies on how not to execute large infrastructure projects.” There seems to be a realisation in government circles that these two power stations cannot be trusted to provide for the country’s future electricity needs as the government prepared itself to move away from coal power stations to renewable energy in its energy road map for the country that has recently been published. Medupi’s power station manager Rudi van der Wal also appears to have given it up as a lost case and has left Eskom to “take up a position overseas.” Eskom confirmed that Van der Wal’s resignation was not linked to the latest blackouts. Energy expert Chris Yelland unpacks what went wrong in the latest loadshedding schedule imposed on electricity users and concludes that it is “the stuff of nightmares.” – Linda van Tilburg

Medupi magic fails Eskom and South Africa – the stuff of nightmares

By Chris Yelland*

Following major problems that brought Eskom’s Medupi power station to its knees during the height of the load shedding last week, Medupi’s power station manager, Rudi van der Wal, is leaving Eskom to take up a position overseas.

Van der Wal had resigned before the mess started, and was due to leave in about two weeks. But after the mess started, he was made to step aside, and was replaced before his pending departure. 

Other staff at Medupi have been dismissed by Eskom’s head of generation, Bheki Nxumalo, for negligence, in what Eskom COO Jan Oberholzer calls “consequence management” following a number of major problems at Medupi that contributed to the load shedding last week.

Additional problems at Medupi power station have now been identified that have not been previously disclosed to the public by Eskom’s management, while Medupi and Kusile are emerging as major threats to the adequacy of the power system to meet demand in South Africa.

For some time, the stackers that load coal from Exxaro’s Grootegeluk mine onto the stockpiles at the Medupi stockyard, and the reclaimers that take coal from the stockpiles to feed coal by conveyor to the power station boilers, have not been working.

So, to get fuel to the Medupi boilers, the coal stockyard was bypassed, and the single main coal conveyor feed from Grootegeluk mine was feeding the power station directly, without any redundancy in the system. So, effectively, Medupi was running with minimal coal stock at its disposal.

Thus, when the 4,5 km single main coal conveyor feed from the Grootegeluk mine failed on the Eskom side with a broken belt, Medupi was left with no coal feeding its boilers other than about one or two shifts worth of fuel in the bunkers at each boiler.

To add to the disaster, it is now clear that blocked chute and belt rip detectors on the conveyor were not working. Thus, the conveyor did not trip when it should have done so in order to protect the system. This caused damage to some 700 m of belt, as well as damage to the conveyor structures.

With the main coal conveyor from Grootegeluk mine down, and the stacker/reclaimers at the Medupi stockyard not working, coal now had to be transported by truck from the stockyard, for offloading at the emergency Buffalo conveyors at the boiler bunkers, in order to get fuel to the boilers.  This was a major logistical nightmare due to the huge volumes of coal involved. Major congestion of coal trucks transporting coal from the stockyard to the bunkers forced the power output of Medupi to be reduced to a third of normal, thus contributing to load shedding

Then problems were experienced with the ash-handling plant, which conveys ash from coal that is burned in the boilers to the ash dumps. Staff working on the bunker feed problems were shifted to deal with the huge build-up of ash, thus compounding the problems.

The good news is that the main coal conveyor from Grootegeluk mine is expected to be operating again shortly, thus relieving the logistical problem of transporting coal by truck and manually offloading the coal at the emergency Buffalo conveyors to feed to the boiler bunkers.

The bad news is that the stacker/reclaimers are still not working. So, with the coal stockyard bypassed, Medupi remains vulnerable and dependent on a single, long, conveyor feed from Grootegeluk mine, without any redundancy if the conveyor should fail or trip for whatever reason.

Summary of issues at Medupi

In summary, the known problems at Eskom’s Medupi power station include:

  1. The main conveyor from Grootegeluk mine feeding coal to Medupi failed, causing belt and structural damage.
  2. Protection devices on the conveyor failed to detect the fault timeously.
  3. The stacker/reclaimers at the Medupi coal stockyard are not working, and the coal stockyard is thus bypassed.
  4. Coal was being transported by truck from the stockyard to the boiler bunkers, causing massive congestion and forcing reduced power output of the generators.
  5. The coal mills are of wrong design, causing excessive wear and tear, with increased maintenance and downtime.
  6. The design height of the boilers is inadequate (i.e. too low), thus causing excessive temperatures within the boiler and flue gas. 
  7. Excessive flue gas temperature is causing premature failure of the pulse-jet fabric filters, which are essential for fly ash collection and pollution control.
  8. The ash handling system is unable to cope with the volume of bottom ash and fly ash from the boilers.
  • Chris Yelland, investigative editor, EE Publishers. 
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Why we can’t retrench: Eskom executive

Eskom chief operating officer Jan Oberholzer says that retrenchments are currently not an option for the embattled power utility because of the high additional costs involved and potential harm to the economy.

In an interview with Beeld, Oberholzer said that job cuts would save Eskom approximately R7 billion a year.

However, he said there are additional costs that need to be paid out to retrenched workers – such as severance packages – which Eskom cannot afford.

Oberholzer said that job cuts of between 10,000 – 15,000 would also cause significant damage to the lagging economy. Bloomberg first reported a figure of 15,000 potential lay-offs at the state company in July 2018.

Despite these potential problems, he acknowledged that Eskom’s output was below par considering the size of its workforce.

“When I resigned from Eskom 11 years ago, the power giant had slightly more than 30,000 people in service and our productivity was better than it is now,” he said.

“Today we work with close to 44,000 employees and also pay for contractors. So something is not right.”

Eskom is currently surviving on government bailouts and sits with debt exceeding R450 billion, which puts the country’s entire economy at risk.

Its financial challenges are mainly due to unsustainable operating costs caused by expensive coal contracts, a high headcount, overall operating inefficiencies, high debt service costs, corruption in procurement and the excessive costs to build Medupi and Kusile power stations.

Bloomberg reported that billions in bailouts for South Africa’s power utility will probably widen the budget deficit to the biggest since the financial crisis, threatening the nation’s remaining investment-grade credit rating.

With the National Treasury’s medium-term budget due for release toward the end of the month, economists in a Bloomberg survey expect a fiscal gap of 6.1% of gross domestic product for this year as money for Eskom, the public broadcaster and national airline sap resources.

That’s compared with the Treasury’s 4.5% February estimate and would be the biggest gap since 2010.

South Africa’s R128 billion three-year package for Eskom will add to state liabilities and widen the deficit, Moody’s Investors Service said last month. It’s the only major ratings company that still assesses the country’s debt at investment grade, Bloomberg said.

Analysts are speculating that Moody’s may cut the stable outlook on the Baa3 rating to negative because of rising debt and lower economic-growth projections, putting the country on the verge of another junk rating.

A downgrade would leave South Africa without an investment-grade ranking for the first time in 25 years.

Article originally from BusinessTech

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Choosing a UPS System 101: The Fundamentals

New to the world of uninterruptible power supply (UPS) systems? Consider this UPS buying guide your introduction to the basic concepts behind UPS Systems and which type will work best for your requirements.

What is a UPS System?
A UPS, at its most basic, is a battery backup power system that supplies power long enough for equipment to properly shut down when utility power fails. It helps prevent loss of data and minimizes the stress a hard shutdown causes on your electronic equipment.

The UPS is also a surge protector that protects connected devices from power problems, like surges or abnormal voltages, which can damage, reduce lifespan, or affect performance of electronic equipment and devices.

Why do I need a UPS System?
In case of a blackout, the UPS switches immediately over to battery power to provide a continuous power source for the length of the battery. Battery life can vary by system and depends on how much power you use. The battery backup gives you time to power down sensitive equipment, servers, or even video game consoles without loss of data or progress. Different UPS systems also provide certain levels of protection for other power problems that arise.

What types of UPS Systems are there?
UPS systems have three different topologies, or categories, based on what type of power protection you need. The three topologies are Standby, Line-Interactive, and Double-Conversion.

What types of power problems do I have?
Many people are aware of only one type of power problem: a blackout. This is when the power goes out and stays out for a few seconds up to a few days. But, many more common power problems exist.

What are common power problems?
Below are definitions of common power problems. If you would like to learn more about power problems. Let’s define possible power problems you might experience:

  • Surge – A brief, but intense, spike in electricity commonly caused by lightning. Surges can damage and destroy electronics, and the intense “spike in electricity” or spike in voltage and current harms circuit boards and components.
  • Blackout – A power outage lasting anywhere from seconds to days. These are most commonly caused by severe weather, utility power shortages, accidents, and power grid failures.
  • Brownout – An intentional or unintentional drop in voltage for an extended period of time. In emergency conditions, power companies may lower the voltage of your electricity to reduce strained resources and avoid a total blackout.
  • Voltage Sags – A sag is also a type of under voltage, but, unlike a brownout, it’s sudden and brief.
  • Over Voltage – Occurs when incoming voltage is higher than normal and lasts longer than a surge but not high enough to be classified as a surge or spike.
  • Frequency Noise – Also known as line noise, frequency noise can disrupt or degrade the performance of a circuit by injecting abnormalities into the system.
  • Frequency Variation – Not a common problem when power supplies are stable, but it can occur when using generators and power frequency fluctuates more than desired.
  • Harmonic Distortion – A departure from the ideal electrical signal on a given power source.

What type of UPS Do I Need?
Make a list of your most common power problems from the definitions above, and use the chart below to pick which topology solves your problems.

What UPS system is right for me?


How Big Does My UPS Need to Be?

In order to make your UPS run properly, your UPS has to be large enough to support all of the equipment plugged into it. You will need to find the UPS capacity. Capacity is how much power a UPS system can provide (measured in Watts). The higher the capacity, the more electronic equipment, and devices it can support. To find the UPS capacity, you will need to calculate the load. The Load is the combined amount of power each of the devices use.

To identify the load, make an equipment list, including the total watts each piece of equipment requires to run properly. Include all of the devices the UPS will need to support. If a piece of equipment has a redundant power supply, only count the wattage of ONE power supply.

If you are unsure how many watts your equipment requires, consult the manufacturer or power supply specifications in the user manual.

Here is an example of an equipment list to verify the load:

Equipment list to verify the UPS load

Once you have calculated your load, count the number of power cords you want to connect to the UPS. Your UPS system will need to have enough outlets to cover the number of power cords.

How much time do I want electricity once the power goes out?
You have already decided your UPS’ topology and what size it needs to be. Now, you need to think about what you would like to do with the battery power when a power problem occurs. Would you like to focus on shutting down all of your connected devices safely? Do you want to keep your DVR and TV running during the power problem? Do you want to finish the section of the video game you are on or just save where you are at?

You must now determine runtime. Runtime is the number of minutes a UPS system can support the attached devices with electricity during a blackout. The minimum runtime is the time you need to complete proper equipment shutdown.

When shopping for runtime, you will be looking at the length of time the batteries in the UPS can support equipment through power outages when utility power is unavailable. Keep in mind the number of watts supported affects runtime: the smaller the wattage load connected, the longer the batteries will last. The larger the wattage load, the shorter the runtime will be.

To determine runtime, we want to look for a range. Begin with the number of minutes it will take to perform complete device shutdown and then build an acceptable range of runtimes. The broader the range, the more UPS system choices you will have.

Runtime example

Do I need sine wave output from my UPS?
Utility power supplies electricity in the form of sine wave alternating current. When the UPS is in normal mode, it passes the same electrical sine wave to your connected devices. If the UPS switches to operate in battery mode, it either produces sine wave or simulated sine wave electricity to power your electronics.

Here is an illustration of a sine wave and a simulated sine wave.

Sine Wave vs. Simulated Sine Wave

You will notice the simulated sine wave output has a power gap at each cycle. Sometimes this power gap may cause stress in the power supply in sensitive electronics, harming them.

You will need a UPS with sine wave technology if you want to plug-in the following:

  • Apple iMac Computers
  • Computers and Equipment that are Energy Star® or 80 PLUS® efficient systems using Active PFC power supplies.

Electronic equipment with Active PFC power supplies may shut down unexpectedly when using a UPS with simulated sine wave output, resulting in data loss or equipment damage. UPS systems that deliver sine wave output prevent unexpected shutdowns and damaging electronic stress.

If you need help determining whether a device uses Active PFC circuits, contact the device manufacturer.

What do I want my UPS to look like?
UPS systems have form factors. The form factor of a UPS indicates the shape and size of its housing. The most common 3 types are:
Desktop or compact
Tower or mini-tower
Rackmount

When choosing the form factor, the main consideration is where you are going to use it. A desktop or compact UPS can hide under a desk, unnoticed. A tower or mini-tower will have a pleasant aesthetic design making it an option to sit on top of a desk or table. A rackmount UPS works well in server rooms.

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Preventing Common Power Problems

Solutions for Spikes, Surges, and More

Uninterruptible power supply (UPS) units (also known as battery backups) and surge protectors guard computers and other sensitive electronics against sudden changes in utility power. They provide a form of insurance for important equipment, preventing component damage and keeping the electric current flowing.

Depending on the location and season, power problems can be both serious and likely. The most common power problems are too much voltage, known as power spikes and surges, and too little voltage, called brownouts and blackouts.

Power Spikes or Surges

A power spike is a burst of high voltage that lasts a few milliseconds. A power surge lasts longer–from 15 milliseconds to several minutes. Surges often happen when large electrical devices switch on and off, or because of faulty wiring or utility problems. Spikes are less frequent, and often result from lightning strikes near connected power lines.

Surge protectors guard against excess voltage. Surge protectors offer data line protection, noise filters for electromagnetic interference/radio-frequency interference (EMI/RFI), and impact-resistant casings for long service life. To protect computers and electronics after a major spike or surge, the metal oxide varistor (MOV) in a surge protector will shut off all power to the equipment. This prevents devices from operating without protection.

voltage 1
Sags, Brownouts, and Blackouts

Sags and brownouts occur when voltage drops below the normal range. In the United States, for example, nominal household current is 120 VAC. A sag can be as short as one cycle (1/60 of a second), while a brownout may last several minutes. A blackout (complete loss of utility power) can result in equipment damage, service interruption, and data loss.

A UPS system will protect against over voltages, like a surge protector, and provide continuous power during a brownout or blackout. Models with automatic voltage regulation (AVR) correct minor variations in input voltage. When utility power drops below acceptable levels, the UPS will supply power from its battery so you can keep working or playing. In case of a blackout, a UPS unit will provide power long enough to safely shut down your equipment and prevent data loss or equipment damage.

voltage 2
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How does an Uninterruptible Power Supply (UPS) work?

An uninterruptible power supply (UPS), also known as a battery backup, provides backup power when your regular power source fails or voltage drops to an unacceptable level. A UPS allows for the safe, orderly shutdown of a computer and connected equipment. The size and design of a UPS determine how long it will supply power.

UPS Topologies

Different UPS topologies provide specific levels of power protection. A UPS will belong to one of these three topologies: standby, line interactive, and double-conversion.

Standby is the most basic UPS topology. A standby UPS resorts to battery backup power in the event of common power problems such as a blackout, voltage sag, or voltage surge. When incoming utility power drops below or surges above safe voltage levels, the UPS switches to DC battery power and then inverts it to AC power to run connected equipment. These models are designed for consumer electronics, entry-level computers, POS systems, security systems, and other basic electronic equipment.

line interactive UPS incorporates technology which allows it to correct minor power fluctuations (under-voltages and over voltages) without switching to battery. This type of UPS has an autotransformer that regulates low voltages (e.g., brownouts) and over voltages (e.g., swells) without having to switch to battery. Line interactive UPS models are typically used for consumer electronics, PCs, gaming systems, home theater electronics, network equipment, and entry-to-mid-range servers. They provide power during such events as a blackout, voltage sag, voltage surge, or over-voltage.

double-conversion (online) UPS provides consistent, clean, and near perfect power regardless of the condition of incoming power. This UPS converts incoming AC power to DC, and then back to AC. UPS systems with this technology operate on isolated DC power 100 percent of the time and have a zero transfer time because they never need to switch to DC power. Double-conversion UPS systems are designed to protect mission-critical IT equipment, data center installations, high-end servers, large telecom installations and storage applications, and advanced network equipment from damage caused by a power blackout, voltage sag, voltage surge, over voltage, voltage spike, frequency noise, frequency variation, or harmonic distortion.

UPS output waveforms

Our UPS systems have either sine wave or simulated sine wave output, depending upon the model.

Sine wave output: The highest quality waveform output is sine wave, which is a smooth, repetitive oscillation of AC power. Enterprise-level UPS systems produce sine wave power to operate sensitive electronic equipment. Sine wave output ensures that equipment utilizing Active PFC power supplies do not shut down when switching from utility power to battery power.

Simulated sine wave output: An approximated sine wave output waveform. It uses pulse wave modulation to generate a stepped, approximated sine wave to supply more cost-effective battery backup power for equipment that does not require sine wave output. The technology used to produce this type of power output is less expensive to manufacture and is common in standby and line interactive UPS systems.

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