# HJ International Latin America, Inc.

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HJ International Latin America, Inc.
Installed capacity of Distribution Transformers. The situation and a proposal of solution. HJ International Latin America, Inc.

Presentation of the situation
There is an excess of installed capacity of distribution transformers HJ International Latin America, Inc.

HJ International Latin America, Inc.
An interesting ratio Invoiced energy, Gwh per year Fi = CITD * fp * 24 * 360 CITD: Installed capacity in Distribution Transformers, GVA fp: Global system power factor HJ International Latin America, Inc.

Determining the magnitude of the Over-Capacity
One indicator of the over-capacity is the ratio between the installed capacity of Power Transformers in the Substations at the end of the transmission lines and ….. HJ International Latin America, Inc.

Determining the magnitude of the Over-Capacity
…. the total installed capacity of distribution transformers reducing medium voltage to low voltage levels. HJ International Latin America, Inc.

Determining the magnitude of the Over-Capacity
In most cases, the ratio R : Installed Capacity of Distribution Transformers R = Installed Capacity of Power Transformers > 2.0 HJ International Latin America, Inc.

Since the flow of energy in the system is the same for Power and Distribution Transformers….. AVERAGE LOAD AVERAGE LOAD DISTRIBUTION POWER TRANSFORMERS TRANSFORMERS = R HJ International Latin America, Inc.

HJ International Latin America, Inc.
Now, transformer size can be selected based on maximum load (Utilization Factor, Fu)... Max Load Fu = Transf. Size HJ International Latin America, Inc.

…or based on the rms equivalent load...
TRANSFORMER AVERAGE LOAD : rms equiv. load La = Transf. size TRANSFORMER OVERSIZE HJ International Latin America, Inc.

HJ International Latin America, Inc.
Then we realize that... If transformers are selected just thinking of maximum load… …this conduces to select capacities much higher than the actually needed. Transformer sizes should be selected as possible based on the average load taken from the actual load curve (projected)… It is important to take advantage of the transformer overload capacity. HJ International Latin America, Inc.

Oversize magnitude comes from...
Ratio R, commented before, and A ratio K depending on the load curve and defined as... K = Fu / La = Maximum load / Average load Maximum oversize magnitude comes from the product given by……. OSmax = R * K HJ International Latin America, Inc.

Since the flow of energy in the system is the same for Power and Distribution Transformers….. AVERAGE LOAD Fu OF THE DISTRIBUTION POWER TRANSFORMERS TRANSFORMERS = R * K HJ International Latin America, Inc.

HJ International Latin America, Inc.
A typical value for K is This makes OSmax = 4.8 Thus, the average load of distribution transformers in the system can be so low as…. HJ International Latin America, Inc.

Immediate goal is... To increase the average load of Distribution Transformers in the System. TIP Importance of the load losses in this process HJ International Latin America, Inc.

Average Load of Distribution Transformers in the system (Instance)
Average transformer ratings may be reduced in the system by factors from 2 up to 5 !! HJ International Latin America, Inc.

HJ International Latin America, Inc.
However…. There are 2 aspects to be taken into account as increasing average load of distribution transformers TRANSFORMER LOSSES TRANSFORMER FAILURES HJ International Latin America, Inc.

Increasing or reducing through higher La in the system??
LOSSES COST... Increasing or reducing through higher La in the system?? HJ International Latin America, Inc.

WHERE WE ARE TODAY INDICATES OUR COMPROMISE
CURRENT SITUATION 20 % WHERE WE SHOULD BE 60 A 75 % HJ International Latin America, Inc.

TRANSFORMER FAILURES It is experienced an increment of overload failures along with a higher “La” in the system UNLESS THE TRANSFORMER BE ADEQUATELY PROTECTED AGAINST OVERLOADS !! HJ International Latin America, Inc.

Our proposal of solution is...
THE SELF PROTECTED TRANSFORMER To increase the Average Load “La” without increasing overload failures To allow the reduction of the Over-Capacity factor “R” along with the losses in the system without increasing other related costs To reduce installation costs To get a significant reduction of the overall transformers failure rate in the distribution system HJ International Latin America, Inc.

HJ International Latin America, Inc.
P – A – U – S - E HJ International Latin America, Inc.

SUMMARY OF THE SELF - PROTECTION PRINCIPLES
A GUIDE THAT SHOWS THE MAIN CONCEPTS TO SUCCESSFULLY INTRODUCE THE SELF - PROTECTION PHILOSOPHY HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 1 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

HJ International Latin America, Inc.
Using Self Protected Transformers is not only to add some components to the transformer…!! BREAKER ARRESTER SIGNAL LIGHT FUSES OPERATING HANDLE & EMERGENCY OVERLOAD HJ International Latin America, Inc.

…it is to use a COMPLETE philosophy to protect and handle with...
THE TRANSFORMERS... HJ International Latin America, Inc.

…it is to use a COMPLETE philosophy to protect and handle with...
...THE DISTRIBUTION SYSTEM... HJ International Latin America, Inc.

…it is to use a complete philosophy to protect and handle with...
...AND THE CUSTOMERS ! HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 2 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

Main transformer protecting tasks, including selection and coordination…
ARE TRANSFORMER MANUFACTURER ISSUES !! BLACK BOX CONVENTIONAL SELF - PROTECTED HJ International Latin America, Inc.

HJ International Latin America, Inc.
This causes... Simplification of the transformers installation Less warranty discussions between Utility and transformer manufacturer Longer warranty terms HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 3 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

HV Fuse should be internally connected
THIS TO AVOID: Fuse rating changed Dangerous operation of damaged units Miss-coordination of the transformer protecting devices HJ International Latin America, Inc.

This arises a question... IS IT NEEDED TO INSTALL THE FUSED CUT-OUT WITH EVERY TRANSFORMER ? HJ International Latin America, Inc.

Some responses from self-protecting principles to this question are:
The load-break operation is made in LV side by operating the breaker operating handle (this is a safer operation) Fuse has one main and one secondary function: MAIN FUNCTION of the fuse is to act like an over-current protection by isolating a failed transformer from the system. SECONDARY FUNCTION is to act like a back-up protection To eliminate the use of fused Cut-out with every transformer it is important to have well trained people to handle with energized lines It is strongly recommended to use Wildlife Guards in those case fused Cut-out is not used HJ International Latin America, Inc.

Cut-outs continue to be an essential part of the distribution circuits for circuit maintenance proposals... SPECIALLY AT THE BEGINNING OF THE CIRCUIT BRANCHES HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 4 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

Signal Light is an essential part of one integral self-protecting policy to get an effective load management OFF SHOWS A NORMAL LOAD OR CIRCUIT SITUATION ON SHOWS AN ABNORMAL LOAD OR CIRCUIT SITUATION HJ International Latin America, Inc.

HJ International Latin America, Inc.
The signal light is an essential part of an integral self-protection policy It’s an easy and economical way to detect any thermal abnormal operating condition without the need of costly measuring and monitoring methods It operates like a PREVENTIVE ALARM without customer disconnection It can be factory calibrated to meet the actual load curve requirements and the desired trip conditions It’s a very effective way to detect energy robbery If attended, it’s a very effective way to reduce non-planned loadbreaks HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 5 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

Arresters are to be installed at the transformer’s tank
IN CONVENTIONAL TRANSFORMERS CUT-OUT FUSES WOULD BE INSTALLED UP- STREAM HJ International Latin America, Inc.

HJ International Latin America, Inc.
Arresters arranged far from transformer tank makes the transformer not right protected HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 6 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

Any overload, at peak hours, above the maximum allowed is to be detected and alarm is to be given by the transformer itself Any transformer giving reiterative alarm information is to be changed for a larger capacity unit. Before that, a load analysis is to be made According to above change policy a SELECTIVE transformers load analysis in the system is made. Signal light acts like a sample selector. Overload capacity of the transformers is to be actually used HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
PRINCIPLE # 7 IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

Assets Management of the transformers in service is to be made
LIKE ANY OTHER ASSET, TRANSFORMER’S LIFE AT THE INSTALLATION PLACE IS TO BE PLANNED ACCORDING TO THE LOAD AND TO A REPLACEMENT POLICY AN INVENTORY ROTATION POLICY SHOULD BE DEFINED ! HJ International Latin America, Inc.

THE SELF - PROTECTION PHILOSOPHY
OTHER PRINCIPLES & FINAL ISSUES IMPORTANT NOTE APPLICABILITY OF THESE PRINCIPLES MAY VARY DEPENDING ON THE PARTICULAR CIRCUMSTANCES OF THE UTILITY HJ International Latin America, Inc.

HJ International Latin America, Inc.
UNBALANCED LOADS UNBALANCED LOADS ARE EASILY DETECTED IN A 3F BANK OF 1F SELF PROTECTED UNITS. UNBALANCED LOADS IN 3F BREAKERS CAN CAUSE PREMATURE SIGNAL LIGHT OR BREAKER TRIP. FOR THIS REASON OUR PRINCIPLE # 6 CALLS TO MAKE A LOAD ANALYSIS IN EACH CIRCUIT CAUSING SIGNAL LIGHT OR BREAKER TRIP. AGAIN SELF PROTECTION PHILOSOPHY APPLICATION ACTS LIKE PREVENTIVE WAY TO DETECT SYSTEM PROBLEMS WITHOUT HIGH COSTS INTERRUPTIONS. HJ International Latin America, Inc.

Making an economical evaluation of a conventional transformers project vs. self-protected project
TRANSFORMER SIZES COMPARED ARE DIFFERENT !! CONVENTIONAL SELF - PROTECTED kVA RATING = X kVA RATING = X/2 HJ International Latin America, Inc.

HJ International Latin America, Inc.
Introducing Self Protecting Philosophy can help to simplify and to reduce costs of Distribution Circuits No use of cross arms for arresters No use of cross arms for Cut-outs Use of line spacers & wildlife guards No LV fuse holders HJ International Latin America, Inc.

HJ International Latin America, Inc.
LOAD HARMONICS LOAD HARMONICS CAUSING OVER HEATING INSIDE THE TRANSFORMERS WILL ALSO CAUSE OVER HEATING OF THE BREAKER’S BIMETALIC, TRIPPING IT. HJ International Latin America, Inc.

HJ International Latin America, Inc.
Breaker Losses ANY COST ANALYSIS OF THE BREAKER LOSSES BASED ON THE ACTUAL LOAD CURVE WILL SHOW THAT IT IS TOO LOW PER YEAR MAKING THE LOW VOLTAGE BREAKER THE MOST ECONOMICAL AND FLEXIBLE ALTERNATIVE TO PROTECT THE TRANSFORMER HJ International Latin America, Inc.

Light & Breaker trip temperatures can be selected based on the kWh demand curve
LOAD CURVE kWh DEMAND CURVE TEMPERATURE PROFIL TRIP TEMPERATURES DETERMINATION HJ International Latin America, Inc.

HJ International Latin America, Inc.
SELF PROTECTION APPLICATION COVERS SMALL DISTRIBUTION TRANSFORMERS (UP TO 500kVA) THAT NORMALLY DON’T USE THERMOMETERS OR LIQUID LEVEL GAUGES BREAKER’S BIMETALIC ACTS LIKE A TEMPERATURE DETECTOR WITH ALARM & TRIP FEATURES WHEN INTERNAL TRANSFORMER’S TEMPERATURES REACH DANGEROUS PREDETERMINED LEVELS BREAKER’S BIMETALIC ACTS ALSO LIKE A LOW OIL LEVEL DETECTOR WITH ALARM & TRIP FEATURES WHEN INTERNAL OIL REACHES LEVELS WHERE THE BIMETAL GET NOT OIL IMMERSED HJ International Latin America, Inc.

Expected life of the transformer oil
DUE TO THE OPERATING TEMPERATURE CONTROL, SELF-PROTECTED TRANSFORMERS MAKE OIL LIFE LONGER THAN CONVENTIONAL POSSIBLE OIL DETERIORATION CAUSED BY UNDER-OIL ARCING IS FAR COMPENSATED BY THE LOW OIL OPERATING TEMPERATURE DURING THE LIFE OF SELF-PROTECTED TRANSFORMERS NUMBER OF BREAKER OPERATIONS DURING TRANSFORMER’S LIFE IS MINIMIZED BY MAKING A RIGHT USE OF THE SIGNAL LIGHT HJ International Latin America, Inc.

Customized thermal protection based on heat run test
THERE IS A DIFFERENT CALIBRATION AVAILABLE EVEN FOR THE SAME kVA RATING TEMPERATURE RANGE FOR TRIP CALIBRATION SIGNAL LIGHT BREAKER OTHER PROTECTING DEVICES LIKE FUSES OR COOPER MAGNEX ARE NOT SO FLEXIBLE HJ International Latin America, Inc.

COMPARISON BETWEEN SECONDARY BREAKER VS PRIMARY MAGNEX INTERRUPTER
HJ International Latin America, Inc.

HJ International Latin America, Inc.
COMPARISON BETWEEN SECONDARY BREAKER VS PRIMARY MAGNEX INTERRUPTER …CONTINUED... HJ International Latin America, Inc.

HJ International Latin America, Inc.
COMPARISON BETWEEN SECONDARY BREAKER VS PRIMARY MAGNEX INTERRUPTER …CONTINUED HJ International Latin America, Inc.

HJ International Latin America, Inc.
SUMMARY We have seen during this presentation: Over capacity problem of the Distribution Systems & causes Our proposal of solution Effect of the over capacity & its solution on losses and failures What is and how works the self protected transformers concept Principles of Self Protection philosophy & performance of a self protected unit in the distribution circuits How to begin a change process to successfully introduce the Self Protection philosophy without mistakes HJ International Latin America, Inc.

HJ International Latin America, Inc.
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