power pack

Power Pack rectifies the Input AC & stores the same in predetermined number of Capacitors to ensure that sufficient DC energy is made available to Circuit Breaker for Shunt Trip operation, during failure of Input AC.


Application

During a fault or undesirable condition of the system, the protective relays primarily operate and give an impulse to the tripping coil of the breaker. To energize the trip coil when this impulse is given, a most reliable auxiliary DC supply is obtained from ‘battery’ which is considered to be the most reliable auxiliary DC supply. In unmanned sub-stations and / or in installations where only one or two panels are installed, the provision of battery becomes quite expensive, as the provision of battery becomes quite expensive, as also its maintenance. In such cases, Power Pack can be conveniently used for obtaining DC supply for tripping.
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General Description

Power Pack is a ‘Capacitor Storage Device’ [also known as : ‘Energy Storage Device’] for Circuit Breaker Shunt Trip & Close Operations, where ‘Batteries’ [DC source for Shunt Trip & Close Operation] are not available [or] viable.

Power Pack rectifies the Input AC & stores the same in predetermined number of Capacitors to ensure that sufficient DC energy is made available to Circuit Breaker for Shunt Trip & Close Operations, during failure of Input AC.

Salient Features
  • Adequate DC energy for energizing shut-trip coil of Circuit Breakers.
  • Built-in capacitors to store energy on failure of AC supply.
  • Trip Supply Healthy Indication by LED (optional)
  • Can be used as “Capacitor Trip Device” in unmanned substation etc.,
  • Application Notes
  • Power Packs Comparison
  • General Description
  • Standard I/O Ratings
  • Construction
  • Technical Data
  • Terminal Drawings

Guidelines for Selection of Input/Output Ratings of Power Pack


Application Notes Pdf »

    Stored Output” of Power Pack

  • This is the ‘Primary’ Output of Power Pack [for which the Product is meant for]. This Output provides “Stored” DC Energy to Shunt Trip & Close Coil Operations.
  • It is generally recommended that ONE Power Pack shall be used per Circuit Breaker.
  • Trip Coil of Breaker shall & must be connected ONLY to “Stored Output” of Power Pack.
  • It should be understood that the ‘Primary’ function of Power Pack is to Trip the Breaker using “Stored Output” even during the worst-case condition: viz., when Input AC to the Installation & to Power Pack has failed.
  • Depending upon type of Circuit Breaker, Close Coil may also be connected to “Stored Output” of Power Pack. In such cases, care should be taken to include this Close Coil load while calculating the “WSec” Rating of “Stored Output” of Power Pack.
  • Other than Trip Coil & Close Coil of Circuit Breaker, no other Load should be connected to “Stored Output” of Power Pack, to ensure beyond doubt that Stored Energy of Power Pack is not wasted/drained unnecessarily.
  • Suitable ‘Inter-locks’ by means of Series Contacts of Relay/Contactors shall have to be provided in Trip Circuit of the Scheme; in a manner that connection from “Stored Output” of Power Pack to Trip/Close Coil be ‘Instantaneously’ cut-off once either a Trip or a Close is complete. This ensures that Stored Energy of Power Pack is not wasted/drained unnecessarily.

    Non Stored Output” of Power Pack

  • This Output is an ‘Optional’ Output of Power Pack and is provided only when specified.
  • This Output provides ‘simple’ rectified DC Output, without any storeage facility for Energy and hence becomes instantaneously ‘Zero Volts’ when Input AC to Power Pack has failed/Off.
  • Depending upon type of Circuit Breaker, Close Coil may also be connected this Output.
  • This Output may be used for illuminating ‘Indicating Lamps’ & other misc. loads.
  • Since this Output becomes instantaneously ‘Zero Volts’ when Input AC to Power Pack has failed/Off, it is generally recommended that operating voltages of loads such as ‘Indicating Lamps’ & other misc loads, may as well be chosen to work directly on Input AC Voltage and shall be connected to accordingly.
  • Foregoing shall help in reducing the general burden on Power Pack and also shall greatly help in reducing the Unit Price of Power Pack.
  • Foreging points shall be taken into consideration while finalising Loads and further, care should be taken to sum-up total “Watts” of “Non Stored Output” required from Power Pack.

    DC Output Voltage of Power Pack :

  • During manufacture, No Load DC Output Voltage of Power Pack, is always set at 110% to 115% of Rated DC Output Voltage.

    Maximum OFF Time :

  • On fully Charged condition of Capacitors [and Power Pack], when Input AC to Power Pack fails /switched-OFF, the Maximum Time for which the Power Pack retains/maintains 80% of Rated Output Voltage on No Load condition = 02 to 04 Hours.

    ‘Shelf-Life’ factor of Capacitors & associated ‘Pre-Conditioning’

  • Power Pack employs Aluminium Electrolytic can-type Capacitors. “Electrolyte” is a high-density Insulating Liquid present inside Capacitors.
  • During normal operation of a Capacitor [ie., when Input Voltage is applied to Power Pack and when Power Pack is in Service], this ‘Electrolytic liquid’ is homogeneously circulated well inside the ‘can’ housing the Capacitor and the Capacitor exhibits its normal Properties.
  • When Power Pack is kept ‘Unused’ [ie., when No Input Voltage is applied to Power Pack] for a prolonged length of time [say, beyond TWO weeks], the Electrolytic liquid slowly ‘settles’ to the bottom of the ‘can’ housing the Capacitor.
  • During this condition when Input Voltage to Power Pack is suddenly applied, the Capacitors [due to settling down of Electrolyte] may not exhibits its normal Properties instantaneously. It might take a little amount of time for the Capacitor to exhibits its normal Properties, ie., until Electrolyte spreads homogeneously inside.
  • This phenomenon is known as : ‘Shelf-Life’ factor of Capacitors.
  • To overcome this ‘Shelf-Life’ factor, ‘Pre-Conditioning’ of Capacitors is done by applying Rated Input AC Voltage to Power Pack for about 2 to 3 Hours, to ensure homogeneous circulation/distribution of Electrolyte inside Capacitor.
  • This ‘Pre-Conditioning’ enables Capacitor to Charge to and deliver the Rated/desired Output.

    LED + Push Button provided for ‘DC Healthy Test’

  • ‘DC Healthy Test’ LED with Push Button is provided, if specified by User, to check for ‘Healthiness’ of DC Output Voltage present in Power Pack.
  • This ‘DC Healthy Test’ LED glows as along as Push Button is kept pressed and thereby provides only an ‘Indication’ to User.
  • The glow of this ‘DC Healthy Test’ LED indicates only the presence of DC Output Voltage. This glow does not in any way represents either the quantum of desired Stored DC Charge or the magnitude of Rated DC Output Voltage required/suitable for the Load [for Trip/Close].

‘Capacitor’ based Power Packs … vs … ‘Battery’ based Power Packs

‘Energy Storage Device’ : As the very name implies, suits ‘Capacitor’ based Power Packs, which have are conventional in design with many inherent advantages, traditionally preferred by most Circuit Breaker & End-Users, all though the years.

There are, however, ‘Battery’ based Power Packs available in the Market. These are Marketed with vehemence. It is for the User to understand the implications & inherent disadvantages of this variety of Product, before procuring the same.

Few Points are Listed hereunder, comparing the TWO Varieties, with a view to educate the User & highlight the implications.
  ‘Capacitor’ based Power Packs  ‘Battery’ based Power Packs
1 Charging Time [after total drain-out] Less than 2 to 3 Seconds Approx. 6 to 8 Hours
2 Maximum No. of Charge-Discharge Infinite No. of Times [No upper limit]

Approx. 50 to 200 Times ONLY

[as recommended by Battery Manufacturer]
3 Component dependability ‘Capacitors’ are widely used in all Electronic Circuits and are proven for longivity & dependability Batteries consists of ‘Cells’ of 1.5 V each. As evident, ‘Electro-Chemical Reaction’ takes place inside ‘Cells’ to produce 1.5 V. [A 12 V Battery has 8 Cells & 24 V Battery has 16 Cells] • Say ~ 110 V is made of 9 Nos. 12 V Batteries [ie., 8 Cells x 9 = 72 Cells] • If ‘Electro-Chemical Reaction’ fails in ONE Cell, then balance 71 Cells Discharge into this defective Cell, resulting in ZERO Volts available for Tripping.
4 Guarantee for quantum of Stored DC Guaranteed. Since ‘Capacitance’ Value remains Constant, always Quantum of Stored DC cannot be Guaranteed. Following Values are Time-bound. due to constant ‘Electro-Chemical Reaction’,:- • 1.5 V produced by each Cell decreases • Ampere-Hour Rating of Batteries decreases
5 Maintenance Practically ‘Zero- Maintenance’, [since it is ‘Passive’ Electronic Component] • Require Periodic Maintenance [by ‘Topping-up’ Acid & Distilled Water, etc.,] • Even if claimed to be ‘Maintenance-Free’ Batteries, above Periodic Checks are to be conducted.
6 Simplicity in Circuit Simple ‘Rectifier’ Circuit To ‘Float-Charge’ Batteries, “Invertor” Circuit is used. • “Invertor” Circuits are complicated and involves many ‘Active’ Semi-Conductor Components. • Failure of any ‘Active’ Semi-Conductor Component leads to TOTAL failure of Power Pack.
 
 

General Description of Product

  

Power Pack is a ‘Capacitor Storage Device’ [also known as : ‘Energy Storage Device’] for Circuit Breaker Shunt Trip & Close Operations, where ‘Batteries’ [DC source for Shunt Trip & Close Operation] are not available [or] viable.

Power Pack rectifies the Input AC & stores the same in predetermined number of Capacitors to ensure that sufficient DC energy is made available to Circuit Breaker for Shunt Trip & Close Operations, during failure of Input AC.


Power Pack has TWO Outputs, as detailed below :-
  • “Stored Output” …… Rated as : “WSec”.
  • This Output is the ‘Primary’ Output of Power Pack which provides “Stored” DC Energy to Shunt Trip & Close Coil Operations.
  • “NonStored Output” …… Rated as : “Watt”.
  • This Output is an ‘Optional’ Output of Power Pack and is provided only when specified.
  • This Output provides ‘simple’ rectified DC Output, without “Stored” DC Energy and hence becomes instantaneously ‘Zero Volts’ when Input AC to Power Pack has failed.
  • This Output may be used for illuminating ‘Indicating Lamps’ & other misc. loads.
When Input AC to Power Pack is present, the Power Pack shall be able to perform any number of Shunt Trip & Close Operations. Hence Power Pack is always Rated for the worst-case condition : viz., when Input AC to Power Pack has failed.

Calculation Procedure of “Stored Output” &  “NonStored Output” of Power Pack :

 

[a]. Calculation of “Stored Output” …… Rated as : “WSec”.

 

The Loads in “Watt-Sec” {‘WSec’ [Stored]} Power Pack has to cater during this condition is calculated and Rating of Power Pack is finalised, as explained below :
1. Using Trip/Close Coil Resistance(s) “R” & Voltage “V”, calculate Watt “W” of Coil(s) using formula : V2 / R = W
2. WSec [Stored] of Power Pack = W [Watt]  x  Operating Time of Shunt Trip/Close Coils in “Sec”  x  “No. of Trip + Close Operations required”
3.

Example : Trip Coil 80W + Close Coil 120W = Total 200W, Operating Time = 50 milliSec and 5 Operations [Trip+Close+Trip+Close+Trip].

Total 200 W x 0.05 Sec x 5 Operations = 50 WSec [Stored]
[b]. Calculation of “NonStored Output” …… Rated as : “Watt”.
This Output may be used for illuminating ‘Indicating Lamps’ & other misc. loads.
1. Watt [NonStored] of Power Pack = Sum-up Wattages of all Loads meant to be connected to this Output.
3. Example : [Lamps 4 Nos x 3W = 12W] + [Load ‘x’ 2Nos x 5W = 10W] + [Load ‘y’ 4Nos x 4W = 16W] + [Factor-of-Safety = 10W]. Total = 48W ~ say 50 Watt [NonStored]
Refer Product Brochure for “Power Pack” for following :
  • Features of Product are listed in detail.
  • ‘Ordering Information’ format. It is requested that all details called-for therein may be furnished, to enable finalisation of Ratings of Power Pack required for any Application.
  • Only after the Ratings of Power Pack are finalised, Unit Price & Dimensional details of required Power Pack are finalised.

    ‘Common’ for DC Output Voltages : 110 VDC [or] 30 VDC [or] 24 VDC

  • Standard Input/Output Ratings of Power Packs, ‘commonly’ used are listed below, along with our Dimensional Drawing Nos. & ‘Type-ref’ of enclosure
  • List below, however, is also applicable for other DC Output Voltages for Power Packs such as : 220 VDC [or] 48 VDC, etc..
  • For ‘Single Phase’ AC [110 V or 230 V] to Power Packs, as a Standard-feature, we provide Terminals for both AC Voltages, to enable User to use any One-pair, depending on Site-condition, without having to depend on us to alter Terminals.

Input Ratings

Output Ratings
SNo VAC
{230 [or] 110}		 Phase WSec
[Stored]		 W
[Non Stored]		 Our Dimensional Drawing Nos. & Type
1 110 V [or] 230 V 1 Phase 20 -Nil- 541 M 1231 ~ Type : D
2 110 V [or] 230 V 1 Phase 20 50 541 M 1216 ~ Type : C1
3 110 V [or] 230 V 1 Phase 20 100 541 M 1216 ~ Type : C1
4 110 V [or] 230 V 1 Phase 40 -Nil- 541 M 1216 ~ Type : C1
5 110 V [or] 230 V 1 Phase 40 50 541 M 1216 ~ Type : C1
6 110 V [or] 230 V 1 Phase 40 100 541 M 1216 ~ Type : C1
7 110 V [or] 230 V 1 Phase 60 -Nil- 541 M 1216 ~ Type : C1
8 110 V [or] 230 V 1 Phase 60 50 541 M 1216 ~ Type : C1
9 110 V [or] 230 V 1 Phase 60 100 541 M 1230 ~ Type : B
10 110 V [or] 230 V 1 Phase 80 -Nil- 541 M 1230 ~ Type : B
11 110 V [or] 230 V 1 Phase 80 50 541 M 1230 ~ Type : B
12 110 V [or] 230 V 1 Phase 80 100 541 M 1230 ~ Type : B
13 110 V [or] 230 V 1 Phase 100 -Nil- 541 M 1230 ~ Type : B
14 110 V [or] 230 V 1 Phase 100 50 541 M 1220 ~ Type : A
15 110 V [or] 230 V 1 Phase 100 100 541 M 1220 ~ Type : A
16 Any AC 3 Phase 20 -Nil- 541 M 1231 ~ Type : D
17 Any AC 3 Phase 20 50 541 M 1216 ~ Type : C1
18 Any AC 3 Phase 20 100 541 M 1216 ~ Type : C1
19 Any AC 3 Phase 40 -Nil- 541 M 1216 ~ Type : C1
20 Any AC 3 Phase 40 50 541 M 1216 ~ Type : C1
21 Any AC 3 Phase 40 100 541 M 1216 ~ Type : C1
22 Any AC 3 Phase 60 -Nil- 541 M 1216 ~ Type : C1
23 Any AC 3 Phase 60 50 541 M 1230 ~ Type : B
24 Any AC 3 Phase 60 100 541 M 1230 ~ Type : B
25 Any AC 3 Phase 80 -Nil- 541 M 1230 ~ Type : B
26 Any AC 3 Phase 80 50 541 M 1230 ~ Type : B
27 Any AC 3 Phase 80 100 541 M 1230 ~ Type : B
28 Any AC 3 Phase 100 -Nil- 541 M 1220 ~ Type : A
29 Any AC 3 Phase 100 50 541 M 1220 ~ Type : A
30 Any AC 3 Phase 100 100 541 M 1220 ~ Type : A

Power Pack consists of an input transformer (1Ø or 3Ø), bridge rectifier(s) and a set of aluminium electrolytic can-type capacitors mounted on varnished-impregnated hylam boards and housed in sheet metal enclosures. The ratings of above components are based on input/output parameters, application and other co-related operations, of specific models of circuit breakers to be tripped. In addition to the stored DC (Power Pack) output, simple rectified DC output (non-storage type) for use as auxiliary DC supply to other interconnected equipments, can also be provided, as an option. ‘DC Healthy Test’ facility for Power Pack output, by means of LED/Push Button combination, can also be provided, as an option.

  • Input – Any AC voltage, 1Ø or 3Ø
  • Output – Any DC voltage, with specified watt-sec rating
  • Maximum assured Shunt Trip operations – To be specified by user, so that Watt-Sec rating is provided accordingly. Minimum charging time shall be five seconds.
  • Maximum Off time – On fully charged co0ndition, the maximum time for which the Power Pack maintains 80% of rated Output Voltage on NO LOAD condition, after the failure of input AC Voltage = 2 to 4 hours.
  • Insulation – Unit withstands 2500V AC RMS 50Hz for 1 sec between earth and all output terminals (as per 15:3231)
Note : Product improvement is a continuous feature. Specifications / Design listed in this publication are therefore subject to revision, without notice.