SAP Ariba – Good or Bad?

SAP Ariba is the leader in spend management. It began with a mission to help companies control spending and cut costs by making it easier for buyers and suppliers to work together. In 2012, Ariba was acquired by SAP, the world’s largest business software company, and in 2016 launched its new new brand identity.

While SAP Ariba is open to all systems and all types of goods and services, its unified name conveys to customers the value of combining solutions for procurement and supply chain collaboration with SAP’s expertise in enterprise application software and supply chain management.

SAP Ariba is how companies connect to get business done. On the Ariba Network, trading partners from more than 3.6 million businesses, operating in more than 190 countries, discover new opportunities, collaborate on transactions, and deepen their relationships.

  • Large, midsize, and growing companies use an end-to-end, automated system that simplifies the management of everything from sourcing to payments, all in one place.
  • With intelligent spend management tools and network-generated insights, customers establish sustainable, trusted connections with partners while ensuring efficient, error-free transactions.
  • Buyers can manage the entire purchasing process as they control spending, find new sources of savings on both direct and indirect goods, and build healthy, ethical supply chains
  • Suppliers can connect with profitable customers and efficiently scale existing relationships, simplifying sales cycles and improving cash control along the way.

The Ariba Network makes it easy for buyers and suppliers to collaborate on transactions, strengthen their relationships, and discover new business opportunities. Buyers can manage the entire procurement process from source to settle, while controlling spending, finding new sources of savings, and building a healthy, ethical supply chain. Suppliers can help buyers achieve their procurement transformation goals, while boosting customer satisfaction, simplifying the sales cycle, and improving cash flow.

Content Source: Ariba.com

In the end it is the choice of the supplier to either join or not. Some of your customers may insist while others are not on the platform, that is all fine at least you are able to make an informed judgement. It might be sales related or foresight to where you want to see your business in the future to join. Our experience over the past years has been good and are able to engage and participate in number of projects easily.

Find Instrument Transformers Limited on SAP Ariba

Need an Instrument Current Transformer or Voltage Transformer?

Drop our technical team an email to discuss your requirement or jump over to our contact form and complete, we would love to hear from you.

G59 Installation Loss of Mains Changes & How it Affects You!

Loss of Mains Change Programme Logo

If you have installed renewable generation before 1st February 2018 in accordance with EREC G59 requirements, then it is likely you will need to undertake an update.

The "Accelerated Loss of Mains Programme (ALoMCP)" is being led by National Grid and run by Distributed Network Organisations (DNO's) & Independent Distribution Network Organisations (IDNO's). 

Covering the United Kingdom but excluding Northern Ireland; it aims to reduce the risk of spurious tripping of the protection system. For renewable electricity generators, this means realigning the RoCoF limits (rate-of-change-of-frequency) in their generation equipment.

If you are a domestic generator of power, then thankfully this does not affect you. However, if you generate & sell back to the grid, using wind generators, hydro or solar PV, means you have until 31st August 2022 to implement the necessary changes. Failure to do so may open you up to an enforcement programme.

Why the change?

RoCoF or Vector Shift (VS) relays usually provides Loss of Mains Protection to prevent "power islanding." RoCof relays were programmed to trip when sensing changes of frequency as low as 0.125Hz. Both these and Vector Shift relays have found to respond to transmission faults that do not cause power islanding leading to low demand disconnections.

Who is responsible for the change implementation?

It's intended that the generators will undertake the settings changes themselves through their qualified contractors. Where a generator doesn't have these facilities, contractors such as ourselves are here to help. Instrument Transformers Limited in partnership with Switchgear Services & Solutions Limited offer changes & complete testing in accordance with the Accelerated LoM programme. Or where necessary, removal of existing LoM relay and install a new relay that is compliant with the new LoM requirements.

Generators can recover the cost of making these changes directly via an online portal located on the Distribution Network Operators (DNO), Independent Distribution Network Operators (IDNO), Energy Networks Association (ENA) & National Grid (NG) websites.

The rates paid for the work will vary from:

£1,000 to £1,500 for change in settings.

£2,500 to £4,000 for a relay change.

Payments will be fixed-rate rather than individual circumstances and are on a first-come, first-serve basis.

Still got questions?

 

or check out more information on the ENA Website Loss of Main Change Programme.

Loss of Mains process at a glance

LoM process at a glance

CT for ANSI & IEC Applications

"Plastic case current transformers are so versitile and simple to install" is a comment customers often tell us. Now its even more enticing, with the devaluation of sterling against a basket of currencies has made this range, even more, cost-competitive leading it to become one of our the best runners for our switchgear and control panel customers.

Designed specifically for IEEE /ANSI C57.13 & IEC 61869 standards, Single Ratio or Multi-Ratio variants complete with integral mounting points. Suitable for Protection/Relaying or Measuring Classes up to 6000A with a 5A secondary makes this robust current transformer makes this a popular choice for our customers.

Secure your order today for this amazing current transformer.

 

Switchgear Protection & Measurement

M78x CT

Protecting Your Ass-ets

Protective Current Transformers are designed to measure the actual currents in power systems and to produce proportional currents in their secondary windings which are isolated from the main power circuit. These replica currents are used as inputs to protective relays which will automatically isolate part of a power circuit.

Satisfactory operation of protective relays can depend on accurate representation of currents ranging from small leakage currents to very high overcurrent's, requiring the protective current transformer to be linear, and therefore below magnetic saturation at values up to perhaps 30 times full load current.

This wide operating range means that protective current transformers require to be constructed with larger cross-sections resulting in heavier cores than equivalent current transformers used for measuring duties. For space and economy reasons, equipment designers should, however, avoid over-specifying protective current transformers ITL technical staff are always prepared to assist in specifying protective CT's but require some or all of the following information.

  • Protected equipment and type of protection.
  • Maximum fault level for stability.
  • Sensitivity required.
  • Type of relay and likely setting.
  • Pilot wire resistance, or length of run and pilot wire used.
  • Primary conductor diameter or busbar dimensions.
  • System voltage level.

A WORD OF CAUTION: RELAY MANUFACTURER'S RECOMMENDATIONS SHOULD ALWAYS BE FOLLOWED

Characterisation of a protective current transformer class is as follows:

Class P & PR  (A current transformer to meet the composite error requirements of a short-circuit current under symmetrical steady-state conditions).

Class PX & PXR (A current transformer by specifying its magnetising characteristic).

Class TPX, TPY & TPZ (A current transformer to meet the transient error requirements under the conditions of an asymmetrical short-circuit current).

Rated Output: The burden including relay and pilot wires generally follow standard burdens 2.5, 5, 7.5, 10, 15 and 30VA.

The accuracy designation "P" (which stands for protection)  uses the highest percentage composite error followed by the Accuracy Limit Factor (ALF).

Standard Protection Accuracy Classes are shown as 5P & 10P with Accuracy Limit Factors 5, 10, 15, 20, 30

Therefore the electrical requirement of a protection current transformer can be defined as:

RATIO - VA BURDEN - ACCURACY CLASS - ACCURACY LIMIT FACTOR

For example, 1600/5A, 15VA 5P10.

Switchgear Protection

Switchgear Protection

Accuracy limit Factor is defined as the multiple of rated primary current up to which the transformer will comply with the requirements of 'Composite Error'. Composite Error is the deviation from an ideal CT (as in Current Error) but takes account of harmonics in the secondary current caused by non-linear magnetic conditions through the cycle at higher flux densities.

Selection of Accuracy Class & Limit Factor.

Class 5P and 10P protective current transformers are generally used in overcurrent and unrestricted earth leakage protection. With the exception of simple trip relays, the protective device usually has an intentional time delay, thereby ensuring that the severe effect of transients has passed before the relay is called to operate. Protection Current Transformers used for such

 

In some systems, it may be sufficient to simply detect a fault and isolate that  circuit. However, in more discriminating schemes, it is necessary to ensure that a phase-to-phase fault does not operate the earth fault relay.

 

Need a Protection Current Transformer, reach out to us and let us help you in your next project.

 

Accelerated Loss of Mains Programme

National Grid ESO and GB Distribution Network Operators (DNOs) / Independent Distribution Network Operators (IDNO) are undertaking electricity transmission and distribution industry-led initiative managed on behalf of the Distribution Code Review Panel.

It is a requirement of the "Distribution Code" that all owners of generation installed before February 2018, and where the generation equipment is not type-tested, to comply with new setting requirements for the interface protection per EREC G59. Owners of generation have to comply with the Distribution Code and have until May 2022 to comply with these modified interface protection requirements. After that date, owners who have not made the change will be the subject of an enforcement programme.

The purpose of the initiative is to consider Loss of Main (LoM) protection and their settings. The aim is to reduce the risk of inadvertent tripping and reduce system balancing issues by giving National Grid ESO more considerable latitude with regards to system Rate of Change of Frequency (RoCoF) limits.

To help owners of generation make the necessary changes, through ENA, National Grid Electricity System Operator (NGESO), the Distribution Network Operators (DNO) and Independent Distribution Network Operators (IDNO), have set up a database to allow generators to register their intention to make settings changes and to facilitate the development of a prioritised delivery programme. This database is available to generators from early-May 2019. It is intended that generators who make the settings changes will be recompensed by the DNO / IDNO they are connected to according to the degree of work involved in making the changes.

Source: Energy Networks Association.

Accelerated Loss of Mains Programme

Achilles – UVDB Registration

The utility market is fast moving, subject to ever more stringent regulation and new technologies. UVDB is the utility industry pre-qualification system used across the UK. Working closely with key buying organisations in the sector, this community helps them achieve the highest standards of supply chain assurance.

ITL is proud to continue its qualified status registration and contributing its part in the high-quality supply chain.

054610

Scope

3.5.20 Transformers - Current

3.5.21 Transformers - Voltage

3.5.99 other Transformers

4.99.5 Testing & Analysis Services (Utilities)

 

 

UVDB Achilles Community Certificate

Agent Appointed – NIGERIA

ITL are happy to welcome Sunria Limited as a representative agent in Nigeria. Located in Ikeja (Lagos State) the companies goal to be a one-stop shop for the power industry resonates with ITL's own goals to be the "Go To Guys" for transformer related equipment.

With the markets desire to return to higher quality products due to poor experiences and the mindset thinking cheaper was better from lower-cost economies. Instrument Transformers Limited brings the necessary quality and is able to design, manufacture and supply cost-effective current transformers and voltage transformers for accurate measurement of power and protection of electrical plant.

Transformers often are hidden from view but are an essential element in our everyday lives. Without electricity in some form, economies cannot grow beyond local bartering on what you can hand make. Electricity gives us industrialisation, innovation and the world we live in. Why wouldn't you want to contribute to that?

Critical to ITL's success is a field support function. A dedicated Engineering & Sales Team members regularly engage and support our international agent network ensuring we understand the techno-commercial aspect of any project and enabling us to exceed an end users expectations, thus guaranteeing additional projects. In addition, regular sharing of market intelligence data allows between ITL & its country agent allows timely adaption of its marketing strategy or deploy extra resources to maximise local market opportunities.

Next time you need a CT or PT and are based in Nigeria, then speak to Sunria Limited on +234 809 984 9392 or email info@sunrialimited.com where they will be more than happy to assist you in your project.

If you would like to be considered as an independent sales agent for Instrument Transformers Limited send an email to Office.ROW@itl-uk.com to start the process.

Agent Certificate for Pakistan

Agent -Certificate

Transformer Accuracy

Transformer Accuracy Principles

Measuring instruments, such as ammeters, voltmeters, kilowatt-hour meters, etc , whether electromechanical or electronic, meet insuperable design problems if faced with high voltages or high currents commonly used in power systems.

Furthermore, the range of currents employed throughout is such that it would not be practical to manufacture instruments on a mass production scale to meet the wide variety of current ranges required.

Current transformers are therefore used with the measuring instruments to:

(a)  Isolate the instruments from the power circuits.

(b) Standardise the instruments, usually at 5 amps or 1 amp.

(The scale of the instrument (according to the CT ratio), then becomes the only non-standard feature of the instrument)

Accuracy classes for various types of measurement are set out in the relevant IEEE(ANSI), CAN/CSA, AS or in our case BSEN /IEC 61869.

It will be seen that the class designation is an approximate measure of the accuracy, eg. Class 1 current transformers have ratio error within 1% of rated current. The phase difference is important when power measurements are involved, i.e. when using wattmeter's, kilowatt‑hour meters, VAr meters and Power Factor meters.

 

Importance of Accuracy

Transformer Accuracy

The table below details the limits of error for current transformers for special applications and having a secondary current of 5A.

 

Design Considerations:

As in all transformers, errors arise due to a proportion of the primary input current being used to magnetise the core and not transferred to the secondary winding. The proportion of the primary current used for this purpose determines the amount of error.

The essence of good design of measuring current transformers is to ensure that the magnetising current is low enough to ensure that the error specified for the accuracy class is not exceeded. This is achieved by selecting suitable core materials and the appropriate cross-sectional area of the core. Frequently in measuring currents of 50A and upwards, it is convenient and technically sound for the primary winding of a CT to have one turn only.

In these most common cases the CT is supplied with a secondary winding only, the primary being the cable or busbar of the main conductor which is passed through the CT aperture in the case of ring CTs  (i .e. single primary turn) it should be noted that the lower the rated primary current the more difficult it is (and the more expensive it is) to achieve a given accuracy.

Considering a core of certain fixed dimensions and magnetic materials with a secondary winding of say 200 turns (current ratio 200/1 turns ratio 1/200) and say it takes 2 amperes of the 200A primary current to magnetise the core, the error is therefore only 1% approximately. However, considering a 50/1 CT with 50 secondary turns on the same core it still takes 2 amperes to magnetise to the core. The error is then 4% approximately, to obtain a 1% accuracy on the 50/1 ring CT a much larger core and/or expensive core material is required.

Still not sure & need help? Feel free to reach out to us with your enquiry where we will be happy to help.

 

CT12-100 MV CT Launch

New 12kV Medium Voltage CT by ITL

ITL proud to announce the launch of its updated medium voltage current transformer CT12-100. Always listening to customer feedback, an area of their frustration was the desire was to allow for changes in the primary ratio rather than only on the secondary. With many such customers requesting the same the die was cast for ITL’s R & D team to improve on existing models to meet their customer's yearning.

In any development, it is important to weigh up the costs and benefit whilst getting the maximum performance from the equipment and at the same time achieve improvements in manufacturing productivity. ITL’s highly skilled engineering & production teams have achieved both in the CT12-100 range.

“The CT12-100 is the first in an updated line of indoor MV current & voltage transformers in development at ITL” Paul Munro (ITL’s Marketing Director) said.

With the Highest System Voltage 12kV, primary ratios from 100A to 1200A designed with both tariff measurement & protection class accuracy in mind ensures that ITL continues to provide their global customer base with the right product for the right job and at the right price.

Got Questions?

Drop our technical team an email to discuss or jump over to our contact form and complete, we would love to hear from you.
New MV Current Transformer

CT12-100

Defining CT Characteristics

Current Transformer Terminology

Current transformers convert an alternating current usually high into a proportional lower one, depending on their use. Measurement type CTs are required to transform the primary current, at various classes of accuracy, as specified by the class designation, over a current range from 1 to 120 per cent of its rated primary ratio.

 

The design of this type of transformer requires a "steel" core and winding wire, typically copper which will when connected to its rated burden (load); perform within the limits of error as indicated by the standard’s specification e.g. IEC 61869 or IEEE C57.13. It is an advantage for a measurement type transformer to saturate above this range, which provides a protection against damage to instruments by limiting the secondary current when surge currents or faults appear in the primary circuit.

 

What Is:

Measuring transformer:

A current transformer intended to supply indicating instruments integrated meter, relay and similar apparatus.

Current transformer:

An instrument transformer in which the secondary current, in the normal condition of use, is substantially proportional to the primary current and differs in phase it by an angle which is approximately zero for an appropriate direction of connections.

Rated primary current:

The value of primary current which appears in the designation of the transformer and on which the performance of the current transformer is based.

Rated secondary current:

- The value of secondary current which appears in the designation of the transformer and on which the performance of the current transformer is based.

Rated transformation ratio:

The ratio of the rated primary current to the rated secondary current.

Current error (ratio error):

The error with a transformer introduces into the measurement of a current and which arises from the fact that actual transformation ratio is not equal to the rated transformer ratio. The current error expressed in percentage is given by the formula:
Current error, percent = (Ka.Is-Ip) x 100 / Ip
Where Ka= rated transformation ratio
Ip= actual primary current
Is= actual secondary current when Ip is flowing under the conditions of measurement

Phase displacement:

The difference in phase between the primary and secondary current vectors, the direction of the vectors being so chosen that the angle is zero for the perfect transformer. The phase displacement is said to be positive when the secondary current vector leads the primary current vector. It is usually expressed in minutes.

Accuracy class:

A designation assigned to a current transformer the errors of which remain within specified limit under prescribed conditions of use.

Burden:

The impedance of the secondary circuit in ohms and power factor.

Rated burden:

The impedance of the secondary circuit on which the accuracy requirements are based. It is usually expressed as apparent power (in VA), at the rated secondary current and at a specified power factor.

Rated output:

The value of the apparent power (in volt-amperes at a specified power (factor) which the current transformer is intended to supply to the secondary circuit at the rated secondary current and with rated burden connected to it.

Highest system voltage:

- The highest rms line to line voltage which can be sustained under normal operating conditions at any time and at any point on the system. It excludes temporary voltage variations due to fault condition and the sudden disconnection of large loads.

Rated insulation level:

That combination of voltage values (power frequency and lightning impulse, or where applicable, lightning and switching impulse) which characterizes the insulation of a transformer with regard to its capability to withstand by dielectric stresses. For low voltage transformer the test voltage 4kV, at power-frequency, applied for 1 minute.

Rated short-time thermal current (Ith):

The rms value of the primary current which the
current transformer will withstand for a rated time, with their secondary winding shortcircuited
without suffering harmful effects.

Rated dynamic current (Idyn):

The peak value of the primary current which a current transformer will withstand, without being damaged electrically for mechanically by the resulting electromagnetic forces, the secondary winding being short-circuited.

Rated continuous thermal current (Un):

The value of current which can be permitted to flow continuously in the primary winding, the secondary windings being connected to the rated burdens, without the temperature rise exceeding the specified values.

Instrument security factor (ISF or Fs):

The ratio of rated instrument limit primary current to the rated primary current. The times that the primary current must be higher than the rated value, for the composite error of a measuring current transformer to be equal to or greater than 10%, the secondary burden is equal to the rated burden. The lower this number is, the more protected the connected instrument is against.

Routine test:

Tests carried out on each current transformer to check requirements likely to vary during production.
Depending on which standard the transformer is to meet e.g. IEC or IEEE/ANSI. In general, the following tests apply to each individual transformer:
1. Verification of terminal markings
2. Power-frequency withstands test primary winding.
3. Partial discharge measurement.
4. Power-frequency withstand test on secondary windings.
5. Power-frequency withstand test, between sections.
6. Inter-turn overvoltage test
7. Determination of errors.
The order of the tests is not standardised, but the determination of error shall be performed after the other test.

Type test:

Tests carried out to prove the general qualities and design of a given type of current transformer in accordance with the requirements of the applicable standers Tests may be carried out on a prototype which may incorporate special arrangements for the measurements required by the applicable standard.
The following tests are type test:
1. short time current test
2. temperature rise test
3. lightning impulse test
4. switching impulse test
5. wet test for outdoor type transformer
6. determination of errors
7. radio interference voltage measurement (RIV) (As specified in IEC 61869-1 for 123kV and above)
All the dielectric type test should be carried out on the same transformer unless otherwise specified.

Special tests / optional tests:

Chargeable testing which may be in the nature of type tests or routine tests, and are carried out only by agreement between ITL & the customer.

Got Questions?

Drop our technical team an email to discuss or jump over to our contact form and complete, we would love to hear from you.
Defining a Current Transformer

Measurement CT