The distribution transformers, switchgear and controlgear are important components of power distribution system. The conformance of these products to standards/specifications is crucial for the reliability and safety of electrical equipment. To ensure high quality of these equipment, testing has to be carried out as per National, International or user specified specifications to qualify them for their intended applications. Thus, availability and access to highly sophisticated testing facilities is a prerequisite for ensuring high quality of material/products. The short circuit test is one of the type tests to be carried out to check the quality and performance of electrical equipment under abnormal conditions, i.e. under short circuit condition.

ERDA had established an “On-line Short Circuit Testing Laboratory” at its Makarpura complex in the year 1998. This laboratory has a capacity of 50kA, 500V for testing of LT switchgear and 80kA, 415V for testing of HRC fuses.

Considering the increasing demands and requirement of low voltage switchgear manufacturers and distribution transformer manufacturers, ERDA has now established an online short circuit test facility of 120kA at 570V for LV switchgear and for 33kV/0.433kV, 4000kVA distribution transformers at Savli at a cost of approximately Rs. 17 crores.

This facility was inaugurated by Shri Saurabhbhai Patel (Dalal), Hon’ble Minister for Industry, Mines, Energy and Petrochemicals, Govt. of Gujarat, on 5th July 2008. Hon’ble Minister also laid the foundation stone of the proposed 1200 kV Impulse Test Laboratory. The projected cost of this is about Rs. 6.0 crores. Shri Balubhai Shukla, Mayor, Vadodara graced the occasion as Guest of Honour, Shri S.K. Negi, MD, GETCO, Shri Anoop Shukla, MD, MGVCL, Shri R.J. Shah, Principal Chief Industrial Advisor, Govt. of Gujarat and Prof. S.M. Joshi, Pro-Vice Chancellor, The M.S. University of Baroda attended the Inaugural Function. The function was also attended by eminent personalities from industry, power sector and academia. Shri Saurabhbhai Patel, in his address congratulated ERDA for setting up such an important test facility in Gujarat and suggested to expand and add to the existing capacity for testing of various equipment. He applauded ERDA for establishing a world class laboratory in Gujarat.


Chief Guest Shri Saurabhbhai Patel delivering the inaugural address	Dignitaries on the dais (L to R) Shri M.K. Patki, President, ERDA; Shri Anoop Shukla, MD, MGVCL; Shri Balubhai Shukla, Mayor, Vadodara; Shri Saurabhbhai Patel, Chief Guest; Shri S.K. Negi, MD, GETCO; Shri R.J. Shah, PCIA, Govt. of Gujarat; Shri A.K. Singh, Director, ERDA	The Chief Guest unveiling the plaque marking the inauguration of the new short circuit laboratory


Front View of 120 kA On-line Short Circuit Laboratory	Chief Guest laying the Foundation Stone for the proposed Impulse Laboratory

Participation in Exhibitions

"South China International Electric Equipment and Technology Exhibition-2008”

ERDA participated in the above exhibition held at Jinhan Exhibition Center, Guangzhou, China during 31^st August - 2^nd September 2008. ERDA had displayed charts showing its capabilities, infrastructure, recognitions, services etc. Many industries from Singapore, Malaysia, Korea, Indonesia and China also participated in the exhibition. The response was very encouraging. A lot of industries looking for export market were keen to utilise the services of ERDA. During the exhibition. Mr. Gautam Bambawale, Consul General of Indian Consulate in Guangzhou visited the stall and interacted with ERDA delegation. The delegation also visited SEARI (Shanghai Electrical Apparatus Research Institute) formerly known as TILVA and STIEE (Shanghai Testing & Inspection Institute for Electrical Equipment) Shanghai, BHT (Beijing Hua Tian Mechanical-Electrical Institute Co. Ltd.) Beijing, M/s HuYu (Huanyu Group Co. Ltd.) Wenzhou, M/s CHINT, Wenzhou etc.


Shri A.K. Singh, Director, ERDA in discussion with a Malaysian visitor	Mr. Gautam Bambawale, Counsul General signing the visitors’ book	Visitors from Dubai in discussion with Director	ERDA team in discussion with CHINT Officials of International Trade Department

Our Director and other executives are visited Zhejian Chint Electrics Co.Ltd., China.

“INDIA ELECTRICITY 2008” International Exhibition

ERDA also participated in the “INDIA ELECTRICITY 2008” International Exhibition organized by the Federation of Indian Chamber of Commerce and Industry (FICCI) and Ministry of Power, Government of India, at Pragati Maidan, New Delhi from 11–13 September 2008.

Prototypes of various technologies developed through its in-house R&D work and charts giving details of various services offered by ERDA were displayed in the exhibition. Efforts were made to explore the possibilities of expanding ERDA activities in the northern region of India. About 500 Visitors from Industries, Academia, foreign countries visited our stall. The response from the visitors was quite encouraging.


Visitors at ERDA stall	Visitors interacting with Shri A.K. Singh, Director, ERDA and other officers	Director flanked by Shri S.C. Angirish, (our Delhi representative) and others

Important Visitors

1. Mr. Joop Hooijmans, Manager - High Power Lab. from KEMA Laboratory along with Mr. B.N. Kishore, Consultant KEMA India visited ERDA on 6^th August 2008. They discussed about areas of mutual interest. KEMA is interested in utilizing ERDA’s facilities for testing various products manufactured by Indian Industries.

Mr. Joop Hooijmans and Mr. B.N. Kishore from KEMA with Director and other officers of ERDA at Savli Laboratory

2. The following experts from R&S, Singapore and R&S India visited ERDA on 18^th August 2008 for technical discussion on EMI / EMC.

1. Nicholas Lai, Product Specialist – EMI/EMC

2. King Wee, Product Manager, MIL Standards

3. Yoon Leon Cha, System Integration Engineer

3. Shri S.K. Negi, Managing Director, GETCO and other senior engineers of GETCO visited ERDA on 22^nd August 2008 for technical discussions.

4. Shri O.N. Narzary, General Manager (Mech) and Head (SMP) Oil & Natural Gas Corporation Ltd., Vadodara visited ERDA on 26^thAugust 2008 along with his colleagues. Shri Narzary showed keen interest in our activities in general and in the training programmes in particular. ERDA has been training GTE’s from ONGC in specific areas for the last two years.

5. Shri P.L. Kulkarni, Group Director, Systems Reliability Group and Shri M.H. Thaker, Head (EMQD / SRG), Space Applications Centre, Ahmedabad visited ERDA on 1^st September 2008 and held discussions with senior officials. They are particularly interested in EMI / EMC testing, metallurgical testing and also wires testing. The visiting officials went round our laboratories and development of long business relationship between ERDA and SAC is expected.

6. Mr. H. Wadhwan, Head – Product Testing, from Voluntary Organisation in Interest of Consumer Education (VOICE) and Mr. Rajeev Ralhan, from Price Waterhouse Coopers Pvt.Ltd., Gurgaon, Haryana visited ERDA on 13^th September 2008. They are particularly interested in utilizing our testing facilities for washing machines.

OTHER ACTIVITIES

Industrial Seminar

The District Industries Centre (DIC), Vadodara and Electrical Research and Development Association (ERDA) jointly organised the “Industrial Seminar” at ERDA on 20^th August 2008. Shri D. O. Shah, General Manager & Jt. Commissioner, DIC graced the function as Chief Guest. In his speech, Shri Shah discussed in detail various government schemes for the industries in Gujarat and also the procedure for availing the same. Many senior industrialists including Shri A. D. Chanpura, General Manager, GSFC; Shri J. B. Prajapati, Chief Manager, GACL; Shri Madhubhai Desai, President, Sardar Estate Industries Association; Dr. Paresh Raval, Secretary, Makarpura Industries Association and Shri Govindbhai Shah President, Dabhoi Industries Association attended the programme apart from many officers from DIC, representatives from local industries and ERDA Officers. Shri A. K. Singh, Director, ERDA presided over the function and in his presidential speech, highlighted the importance of energy audit and ERDA’s activities in this area. Our scientists made two technical presentations namely Energy Audit and Energy Saving Potential and ERDA’s R&D Activities on the occasion.

The participants showed keen interest in the presentations and also went round the laboratories.


Shri D.O. Shah, General Manager & Jt. Commissioner, DIC inaugurating the programme	A view of the audience

IEEMA IT Division Meeting

ERDA hosted IEEMA Instrument Transformer Division Meeting on 25^th September 2008 at its Vadodara Campus. Members showed keen interest in our facilities and they also gave some suggestions to update our facilities. ERDA agreed to consider the same. The members of the committee were taken to our Savli Laboratory to visit our On-line Short Circuit Test Facility.

Shri A.K. Singh, Director, ERDA with the IEEMA Team

RAC Meeting

The Twentieth Meeting of the Research Advisory Committee of ERDA was held on 26th September 2008 under the Chairmanship of our Vice – President Dr. J.J. Patel. Presentations were made on the 24 R&D Projects by the respective Project Investigators. This included sponsored, internal and completed projects.

TUTORIAL PLANNED

ERDA proposes to organize a tutorial course on “Power Electronics & AC/DC Drives” from 02^nd to 06^th December 2008. Prof. S.K. Gosavi, visiting faculty, M.S. University of Baroda is the main faculty for the same. The course aims at refreshing the fundamentals and application of AC-DC Drives used in:

[1] Cold Rolling Mills
[2] Cement Industries
[3] Machine Tools

Practicing Engineers having Graduate / Post Graduate qualification with 2 to 5 years experience will gain major benefits.

Those interested may write to Director, ERDA.

Abstract— Bulk consumers with captive power plant prefer to generate electrical power for their own use from the waste heat or by product. They generate electricity for reliable, quality, cost effective and un-interrupted power supply. The bulk consumers with captive power plant preferred to have parallel connection with utility grid to supply the surplus power to the grid or to import additional power from the grid as per their requirement and to maintain stability. The bulk consumers with captive power plant are having certain types of fluctuating loads like arc-furnace, induction furnace, rolling mills etc. This type of load generates harmonic, negative phase sequence voltage and negative phase sequence current, voltage flickering etc. These are the power quality parameters generated by such types of loads and are harmful to the system. If the bulk consumers with captive power are connected with grid, grid absorbs this ill effect to larger extent because fault level at Point of Common Coupling is normally very high compared to fault level contribution by CPP units. Because of higher fault level, CPP can function more reliably and efficiently.

I. INTRODUCTION

Eelectrical power is essential raw material for economical growth of industry today. It is required as a continuous flow- it cannot be conveniently stored in quantity - and it cannot be subject to quality assurance checks unlike other commodity at manufacturing stage.

What do we mean by ‘power quality’? A perfect power supply would be one that is always available, always within voltage and frequency tolerances, and has a pure sinusoidal wave shape. Just how much deviation from perfection can be tolerated depends on the user’s application, the type of equipment installed etc.

Power quality defects – the deviations from perfection – fall into five categories: –

1.       Harmonic distortion
2.       Under or over voltage
3.       Dips (or sags) and surges (Swells)
4.       Transients
5.       Flicker

Each of these power quality problems has a different cause. Some problems are result of the shared infrastructure. For example, a fault on the network may cause a dip that will affect some customers and the higher the level of the fault, the greater the number affected. A problem on one customer’s site may cause a transient that affects all other customers on the same subsystem. Other problems, such as harmonics generated within the customer’s own installation, may or may not propagate onto the network / affect other customers. Harmonic problems can be dealt with by a combination of good design practice and well proven reduction equipment.

ERDA has studied various system data and system parameters of selected CPPs. ERDA had measured various system parameters like harmonics, unbalance current, plant load factor, load cycle, fault level calculation etc. by measurement at selected CPPs and relevant substation.

1) Independent Power Plant (IPP): This power plant consists of only generating plant. This power plant exports the generated electric power to utility grid.

2) Captive Power Plant (CPP): This power plant consist of generating plant with process plant industry. Parallel operation provides CPP to export surplus electricity and source of imported power in emergency / need.

When the industrial plant generates part of its own electric power and purchase the rest from the utility system, it is always highly desirable for industrial plant to operate the generating plant in parallel with utility system to obtain the most flexible, reliable and efficient operation for industrial plant.

The bulk consumer with CPP prefer to run their plants in parallel with grid supply to get instantaneous peak power demand during the starting of heavy equipment like motor, electric furnace etc. This instantaneous peak demand in many cases is much higher than the installed capacity of the captive power plant. Alternatively CPP is required to install the generator of much higher capacity. Thus by parallel operation, the bulk consumers save the cost of generating plant which is required for supplying the instantaneous peak demands in isolated mode of operation. Captive Power Plants are expected to have higher fault level when connected at higher voltage level & thus reduces the voltage drop. Parallel operation facilitates running the captive power plant at higher Plant Load Factor. In the absence of utility connection, the CPPs will have to operate their plants at lower plant load factors which is not desirable economically for CPPs. Thus bulk consumers are getting advantages in financial as well as in technical respect by connecting their plant in parallel with the grid.

II. OBJECTIVE

1. Study of electrical parameters i.e. change in voltage, frequency, power factor, MVAr, MW loading for industries (having high intensity fluctuating loads) during incidence of high intensity peaking load.

2. Study of harmonics produced by industries having fluctuating loads and unbalance loads.

3. Study of voltage unbalance and negative phase sequence current and voltage during operation for different types of industries.

III. METHODOLOGY

The above mentioned study was carried out at 10 sampled industries, which draw power from their CPPs. The CPPs were selected based on their processes like Cement, Aluminum, sponge Iron, Ferro-Alloys and based on the major loads connected like Arc-furnace, Rolling mill etc.

ERDA has carried out the measurement at following two locations at each selected CPPs for 24 hours:

The power quality parameters were measured using precision power analyzer having accuracy up to 0.03 % and capable to record up to 99^th order of harmonics. The system voltage and the load current were fed to the recording device through system PT/CT. The voltage and current waveforms were analyzed up to 25^th order of harmonics using the Fast Fourier Transform (FFT) algorithm. The total harmonic distortion (THD %) is computed as given below.

The measurement of power parameters (Viz. Active power, Reactive Power, Apparent Power) is carried out by averaging the data for every 30 seconds. The sampling rate used is 3MHz per channel.

Percentage of unbalance in three phase current and three phase voltage is calculated from the I_rms and U_rms measured at sites.

IV. RESULTS

Short circuit is a very important concept in power system. For instance, it is often specified or referred to as a contractual value, as far as voltage fluctuations are concerned in medium voltage or high voltage power system. The voltage fluctuation caused by fluctuating loads are strongly depending on the impedance of network at point of common coupling (PCC), which is classically related to the concept of short circuit level.

In addition to the measurements of power quality parameters, the fault level at point of common coupling (PCC) have been computed through system study analysis as total fault level and quantum of fault level contributed by CPP.

From the above data, it is clear that the fault level at point of common coupling is very high compared to the fault level contributed by individual captive power plant.

V. CONCLUSION

From the above technical studies and results obtained, we can summarize the following:

The above are the results of power quality parameters measured for 10 nos. of sampled Captive Power Plants. From above it is clear that grid provides support through parallel operation in terms of:

ACKNOWLEDGMENT

The authors acknowledge the support received from officers of CPPs during the study.

Sr. No.	CPPs	Fault level at point of common coupling (MVA)	Fault level contributed by CPP (MVA)
1	A	9609.60	2540.20
2	B	3446.50	1095.20
3	C	507.50	86.80
4	D	1393.50	167.90
5	E	2956.30	71.50
6	F	109.00	20.30
7	G	1155.60	59.70
8	H	1230.10	156.70
9	I	653.30
10	J	287.60	55.90