UPS: Up Goes the UPS

Telecom service providers account for approximately one-third of the UPS
customer market. Typically, the market is cyclical since it is primarily driven
by ramp-ups in infrastructure. Since the initial buildup involves major capital
expenditure and sustains for a period of 3—5 years, the next phase or the next
rollout often comes after this period.

Sometimes the market dynamics in the telecom space change drastically because
of other reasons also. For example, last year, cellular operators who received
licenses to operate as the fourth cellular providers in particular circles,
invested in building new infrastructure, leading to a spurt of growth in the
telecom vertical.

In order to offer continuously high levels of services, the
power-architecture deployments at telecom service providers necessarily need to
have multiple redundancies built in, considering that downtime can create huge
financial losses. For any enterprise, an uninterrupted power supply (UPS) is the
core component of a good power-conditioning architecture.

Impact on Business

MAIT and Emerson Network Power India, along with Feedback Consulting carried out
a survey in Dec ember 2003, across six cities, eight segments, and covering 302
firms (22 from telecom and IDC/ISP vertical) on network power downtime.
According to the study, India could be losing over Rs 22,000 crore in direct
losses, due to poor power quality and operating environment related downtime-estimated
to be around 2.2 percent of the gross output of the total industrial and service
sectors.

For service providers (SP), it is very critical to have their power needs
carefully listed with the assumption that 99.999 percent availability is an
expected norm and non-delivery results in high penalties.

Power Architecture at SPs

• DC Power Supplies with multiple redundancy and battery backup for four to
  eight hours.

• Redundant UPS Systems with load bus synchronization and
  redundant distribution, to provide a high 9s uptime solution.

• Load Bus Synchronization or LBS is required to keep the
  output of the two UPS systems in sync, so that loads can be transferred
  seamlessly between them.

• Super Switch, an automatic static transfer switch (STC)
  that enables ultra fast switching between two independent AC power sources
  to provide uninterrupted power. When used with redundant AC power sources,
  it enables maintenance without shutting down critical equipment.

Latest Technology Trends

• Stackable UPS systems

• IP-based UPS system monitoring software

• High-performance UPS systems with voltage accuracy for
  non-linear loads

• Lower input power consumption

• Wide input voltage range based on load level-for remote
  locations.

• New compact designs save space.

• Low component count for greater immunity to noise

• Advanced battery management for better battery life

• Advanced communication with networks SNMP for remote
  management

• Redundancy and scalability

Geographies and Power Requirements

The Telecom Engineering Center (TEC) has laid out certain specifications for
mobile switching centers (MSC). As per these guidelines, each MSC should have a
DC power system that provides between 4—8 hours of backup. Over and above this
minimum, geographies step in to dictate the exact nature of the power solution.
For instance, voltage fluctuations would vary across different locations. An MSC
in a city like Mumbai, with a ±10 percent voltage range, could function with
merely a DC power system vis-à-vis a more remote place that faces a higher
voltage variation, which would necessarily require a generator set and a voltage
stabilizer at the input source of power. Also, in the case of UPS systems used
for the billing computers and OMCTs, the backup time for UPS systems in remote
places would be greater than in the case of metros. While in cities like Mumbai
the UPS backup time could be half an hour, in other locations where the UPS is
utilized as an alternate source of power, the backup time may need to extend up
to two hours, at the minimum. Other than availability of power, its quality and
the number of hours it is available in a region, also influence the power
requirements.

Power at a Few Service Provider

VSNL, a leading service provider to most of the top 500 corporations in the
country, has a power solution that includes power supply, power distribution,
cooling, and a few other components which give it a 24x7 power-availability
quotient. According to VSNL, their endeavor is to rule out downtimes of any kind
to maintain a quality of services to their customers.>

Sify requires 100 percent uptime, given the nature of its business as an ISP.
The losses it could incur in case of an outage would be enormous in terms of
loss of data, failure of communication links, discontinuation of services, end
of physical security services, loss of revenue, and loss of faith in business
from the customers. To align its business needs, Sify has made heavy investments
to build and design its power layout. It uses UPS systems in parallel redundant
mode (PRS) for redundancy at its NOC locations. These are provided with battery
backups that can sustain for over four hours.

In addition, all these locations are provided with diesel gensets as a
secondary backup to the mains power. The center has two feeds for power supply,
in the form of a ring mains supply. It has a 2N redundant power network that
includes transformers, generators, HT/LT distribution, cables, and UPS units,
all in multiples of two, to ensure that there is not even a single point of
failure.

Power Conditioning Needs of GSM Operators

• Main Switching Center (MSC) & Base Station Controller (BSC): The
  customer equipment-which includes main switch exchanges, home location
  server-is heart of the business communications. Power disturbances can
  wreak havoc with these high-end, microcontroller-based systems. Many of
  these networks also require a separate DC power sources for operation.
  Dedicated equipment rooms are in need of extra cooling for rack-mounted
  enclosures.

• Base Transreceiver Station (BTS): Telecom shelters
  and other remote sites have very different requirements from larger,
  centrally located installations. Because, they are usually unmanned, are
  located in a wide variety of climates, are often at the end of a long
  utility-power circuit, and in any case the remote sites pose special
  environmental and power problems. The reliability and monitoring required
  for them is also different, depending on the criticality of the
  facility. 

Calculate Your Power Requirement

The power requirement is calculated based on a zonal system. Pure user zones
are calculated at 1.4 times of power needed for a desktop equipment. Server
zones are calculated based on power requirements of servers, calculated at
present plus future growth with a 40 percent add on.

Minu Sirsalewala

Sify's Power Conditioning Policy

Sify has a well-documented power conditioning policy. It ensures that:

• All electrical components meet IS/IEC standards during and after
  installation

• Incoming power parameters like voltage, frequency, and
  the 'power factor current' in each phase are monitored on a regular
  basis and corrective action taken immediately if there are irregularities

• All UPS output parameters like voltage, frequency, power
  factor, and current; and generator parameters like speed, voltage, and
  frequency in each phase are monitored. And necessary adjustments are made as
  and when necessary

• Regular preventive maintenance of power equipment is
  carried out. They also carry out insulation tests to ensure cable and
  distribution bus bar has strong insulation between phases and neutral, and
  between phases and earth

• Conduct power audits once in six months to check
  transient voltage, harmonic levels, noise, waveform distortion, and
  frequency variation and make the necessary corrections. Check actual versus
  defined current levels in the cable and bus bar, to ensure there are no
  overload situations

• Ensure pure and clean output power to the equipment, which is not affected
  by sags, surges, spikes, noise, harmonics, low/high frequency, and power
  outages

Preventing and Preparing for Power Outages

UPS Components