October 17, 2002
Mr. Mario Posillico
Incorporated Village of Saltaire
P.O. Box 5551
Bayshore, New York 11706
Re: Inc. Village of Saltaire Power Quality Monitoring Evaluation
Dear Mr. Posillico,
We are pleased to present our evaluation of the power quality monitoring conducted throughout the village of Saltaire, New York. This study evaluates any disturbances, such as voltage spikes, dips, and losses, recorded during the monitoring periods along with information provided by the local utility (LIPA). This study also provides insight on grounding systems and methods for ensuring proper grounding.
The power monitoring was conducted by Wire to Water, a local electrical contractor. Power monitoring equipment was placed in the village Hall from July 23, 2001 thru August 20, 2001 and the Saltaire Incinerator from August 23, 2001 thru February 12, 2002. For reference, a typical single phase to neutral waveform is shown below.
During disturbances waveforms typically, become distorted for a varied period of time depending on the type of disturbance (i.e. phase loss, system voltage sag, etc...) but usually return to the a waveform very similar to the waveform shown above.
The Village Hall is provided with a 120/240 Vac, 200A Single Phase, Three Wire electrical Service from LIPA. The Electrical Utility provides power to the Village Hall via overhead service mast. This is a typical service size/type for a building of this size and usage. While power monitoring was underway, a total of five (5) power outages were recorded. In all instances, the same phase lost power but returned immediately thereafter. The dates of these outages were 7/24/01 @6:07 PM, 8/7/01 @8:31 AM, 8/10/01 @4:41 PM, 8/10/02 @4:48 PM, 8/20/02 ~ 2:53 AM. A representative waveform showing the above mentioned disturbance is shown below:
As illustrated in the above waveform the voltage loss was complete for approximately 350 milliseconds (0.35 sec) and then returned to its normal voltage. A power loss such as this is unlikely to harm any equipment but is long enough to restart typical home computers. It is suggested that small UPS systems (relatively inexpensive and obtainable at local stores) be provided for village computers to prevent any inadvertent data loss. In addition to the phase loss on 7/24/01, the remaining phase had severe voltage sag. This sag would behave like a "Brown Out" where lights would dim and would brighten once the full voltage returned. All of these disturbances are really typical of any residential or even light commercial electrical services.
The Saltaire Incinerator facility is provided with a 120/240 Vac, 200A Three Phase, Four-Wire electrical Service from LIPA. The Electrical Utility provides power to the Incinerator facility via underground electrical conduit. This appears to be an adequately sized service for a facility of this size and usage. While power monitoring was underway, a total of three disturbances were recorded. In all instances, the disturbance returned to normal operating conditions in less than 6 cycles (approximately 0.1 sec). The dates of these outages were 10/9/01 @11:03:53 AM, 10/9/01 @ll:0l:56 AM, and 11/26/01 @ 10:26AM. In addition to power outages, multiple voltage sags were also recorded. A representative power loss waveform showing the above mentioned disturbance and a representative voltage sag waveform is shown below
Based on the recordings of the Incinerator facility, there did not appear to be any atypical events for general electrical utility service. Please note that there was no disturbance recorded during the incinerator motor controller failure. It would appear that the failure was an equipment related failure and was not associated with any abnormal electrical utility service.
The Electrical Utility (LIPA) servicing the Incorporated Village of Saltaire reviewed our request for information from our letters dated October 23, 2001 and April 22, 2002 and met with H2M and a representative from Saltaire at Saltaire on April 10, 2002 to discuss the Villages concerns. The Electrical Utility was unable to provide us with a detailed mapping of the area due to increased security measurements currently in place. The Utility did, however, provide us information in letter form dated May 2, 2002. In the letter, the Utility states that it is currently involved in providing system enhancements at the Village of Saltaire. This system enhancement includes the addition of a second phase from Pole #112 at the corner of the Light house Promenade and Neptune Walk to Pole #17, located on Neptune Walk. The Utility states that this measure is being made to correct under-voltage during high load periods (typically the summer months), not to correct voltage sag conditions. The Village should notice increases in utilization equipment (household appliances, Pumps, motors, etc) efficiency during high load periods once this system enhancement is completed.
As mentioned during the site visit with LIPA, the village is currently utilizing mostly copper and some aluminum feeders throughout the system. This is standard practice throughout the United States, as many areas still use mostly copper overhead primary feeders (i.e. Fire Island). Utilities typically use aluminum or copper as current supply and availability dictates. Copper primary feeders are more expensive and are usually heavier than aluminum feeders. Copper feeders are, however, more naturally suited for environments like Saltaire that are located in marine areas. Although the utility uses aluminum feeders, the feeders are insulated from the elements and meet all performance and safety requirements set forth by the National Electrical Code (NEC) and the National Electrical Safety Code (NESC).
The Electrical Utility also stated in the letter dated May 2, 2002 that there are no PCB transformers in service by the Electrical Utility at the Village of Saltaire as per the Environmental Protection Agency regulations.
Based on the power quality measurements, it appears that the Electrical Utility, with its system enhancement, is providing adequate power to the Village of Saltaire, as the power outages shown are typical. The utility is providing electrical utility within its acceptable ranges. Permanent Monitoring in a selected area could provide a more detailed history and provide evidence in future disturbances.
Existing Grounding Systems
During our site visits to the Village of Saltaire, it was brought to our attention that much of the Main water service piping was no longer metal and most residences were still utilizing the incoming water main as their main source of earth ground. The National Electrical Code clearly states in section 250 the absolute need and requirement for proper grounding, for both equipment and services. The National Electrical Code defines a metal underground water pipe as:
"A metal underground water pipe in direct contact with the earth for 10 feet or more (including any metal well casing effectively bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or sections or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors."
Due to the removal of much of the metal piping, any and all grounding conductors grounded to this metal pipe may not be considered sufficiently grounded even with the small supplemental grounding electrodes. The National Electric Code states in section 250-52 (c) that a rod and pipe electrodes shall not be less than 8 ft. in length.
Most importantly, the National Electrical Code requires a minimum resistance to ground of 25 ohms and additional electrodes shall be provided at not more than 6 ft. apart until the minimum resistance to ground of 25 ohms is obtained. Please note that this is the minimum requirement and takes into account a wide range of variables such as location, climate temperature, and soil type. While compliance of the Code requires a minimum resistance to ground of 25 ohms, we recommend a resistance to ground of 10 ohms. Ideally, the resistance to ground should be as low as possible in order to, as stated in 250-2 (a), limit the voltage imposed by lightning, line surges, or unintentional contact with higher voltage lines and that will stabilize the voltage to earth during normal operation. We strongly suggest the Village investigate all areas that have modified water-piping systems to ensure that the grounding is sufficient. A qualified electrical contractor should be able to investigate these areas of concern. H2M can provide a list of contractors to the village as necessary.
While insufficient grounding external to any residences may exist, improper grounding at the service entrance equipment may also exist. Examples of improper service entrance equipment grounding can vary from poor bonding (by code, bonding must be made either through exothermic weld or listed compression type lug), insufficiently sized grounding
conductor, and weathered rusted connections. Most electrical contractors can easily rectify an evaluation of the ground conductors.
Recommended Surge Suppression System
Usually, good grounding is adequate for residences but in some instances where special or expensive equipment is being utilized or surges are more periodic, a small Transient Voltage Surge Suppression system may be installed. A popular system currently being sold for residences and light commercial facilities is the MCG Electronics model 90M. This surge suppression system provides a robust warranty and can easily be installed by a local electrician.
If you have any questions please do not hesitate to contact me at 631-756-8000 ext. 1010 or Jeff Czajka at 631-756-8000 ext. 1413.
Very truly yours,
HOLZMACHER, Mc LENDON & MURRELL, P.C.
George Skrelja Project Engineer