WO2001048498A1

WO2001048498A1 - ELECTRICAL FLASHOVER MONITOR-E FOM?x+¿

Info

Publication number: WO2001048498A1
Application number: PCT/IN1999/000066
Authority: WO
Inventors: Sudha Shankar; Raman Venkata Raghavan
Original assignee: Udaya Shankar, Srikantiaha, Rama, Rao
Priority date: 1999-11-24
Filing date: 1999-11-24
Publication date: 2001-07-05
Also published as: AU2318400A

Abstract

Problems of electrical equipments generally arise due to over heating from loose connection and/or poor connection. To avoid this, an electrical flashover monitor protects and monitors the loose connections by means of a set of sensors (2) fixed near/inside the equipment (1). Temperature thus sensed is fed to a micro processor (4) based software driven programmable temperature data logger/scanner which gives continuous display (5) of the temperature monitored. When the temperature exceeds the preset value, which is more than the maximum temperature attained by the monitor device when the ambient temperature is maximum and rated maximum permissible current is flowing through the equipment (1) an alarm is initiated so that corrective action can be initiated.

Description

DESCRIPTION

TITLE OF INVENTION

Electrical flashover monitor

FIELD OF INVENTION

This invention relates to an apparatus titled ELECTRICAL FLASH OVER MONITOR for on line automatic and continuous Electrical loose connection, flashover and protection against the same in any of the electrical equipments) including the parts of equipment(s), electrical bolted joints, links, contact points, junction boxes, cable terminations in motors, generators, power and motor

control centers and cubicles having cable terminations, flexible secondary connection of transformers / generators, joints in Bus Ducts and any other equipment where it has to be guarded against High temperature, otherwise, which may cause fire hazard, explosions or any other environmental disaster

there of including destruction of property. This invention is, therefore, referred to as ELECTRICAL FALSH OVER MONITOR REPRESENTED AS E - FOM^x+

The object of this invention is to provide an excellent continuous, automatic, on line, monitoring and protective device against loose connection and flash over in any of electrical equipment(s) including the parts(s) of the equipment, electrical bolted joints, links, cable joints, cable termination on to motor Terminals, cubicles, Bus bar chambers, fuse switch units, Motor and Power control centres, Flexibles secondary connection of transformers and any

other equipment, which needs to be guarded against high temperature in advance so that corrective action may be initiated and unscheduled stoppages / destruction of equipment monitored is prevented. This also increases the

equipment availability and reduces equipment down time. The basic guiding principle of the said invention is "any loose connection generates abnormal quantity of heat which if not detected and prevented will result in electrical flash over and or destruction or failure of the equipment." By continuously monitoring the temperature of the electrical cable joints, cable termination in motor control centers, power control centers, motor terminals, current transformers, power transformer and bus bar joints, flexibles of transformer,

secondary connection wherein heavy current flows, appropriate action can be initiated so that any electrical flash over and or failure / destruction of the equipment is prevented.

The first apparatus of the invention consists of Bolt-on or Button type / adhesive type 0 - 200° C/K type Thermo Couple or PT 100 RTD /

Temperature sensors with protective covering to protect the sensor against corrosion, high temperature and any other adverse ambient conditions which may destroy the sensor, aiongwith sufficient length of leads which will be terminated on to a temperature scanner / data logger.

The second apparatus of this invention comprises of microprocessor based software controlled temperature scanner / data having the following facilities :

a) Programmable key board to select type of temperature control and sensor inputs. b) Provision to work as temperature indicator, scanning different channels, data logging, with latching relay contacts for alarm and trip.

c) Provision with a selectable time delay for alarm so that nuisance / false alarm due to transient temperature surge is

avoided. d) Has provision to set up different individual setting temperatures for each channel; e) Each channel has latched relay contacts actuating at programmed set temperature values - one for alarm and other for tripping of the equipment which is monitored / cutting off electrical supply to the equipment; f) Printer facilities to provide record of temperature monitored so that Thermal profile of equipment can be studied with normal graph in Black / Blue and Red colour for high temperature. g) Date for each 24 Hour period. h) 72 Hours battery back up for calender, programmed data and real time clock,

i) Log-in- facilities with pass word so that only authorised person can programme the data / alter the set points, j) Continuous scanning for all channels for high temperature / hot spot points so that alarm is actuated, k) Protection against failure of sensors and sensor leads open circuit for each channel so that corrective action can be

initiated. I) Channel skip facilities so that during fault rectification of faulty channel, nuisance continuous alarm is avoided, m) Digital display of monitored temperature / high temperature;

n) Programmable scanning and sampling frequency depending on application and criticality of the equipment, o) Facilities for alarm, led display software self test in a sequence so that by pressing of one key all hardware, software, display tests are done, p) Channel arrangement at site; q) All programming done by Key Board Operation data logger; r) Individual relay status for all channels is displayed; s) 24 - 240 V AC/DC control supply; t) Record of last 10 dates when temperature has crossed set points for each channel both alarm and trip.

This invention, E-FOM^x+ therefore monitors an apparatus on continuous basis and protect it against loose connection and / or flash over in any of the electrical apparatus including parts of it like electrical bolted joints / links, cable joints, cable termination on to motors, power and motor control

centers, bus bar chambers, fuse sv/itch units, flexible secondary connections of transformers and any other equipments which has to be guarded against high temperature in advance so that corrective action may be initiated to prevent unscheduled stoppages / failures of monitored electrical equipment. This also maximises equipment availability resulting in increased output from connected utilities / services as the case may be.

The apparatus consists of a plurality of 0 - 200° C 'K' type

Thermo couples / PT - 100 resistance temperature detectors either bolt on / button / adhesive type arranged in an array. The number of sensors being depending on the degree of monitoring required with more number of sensors fixed at all electrical joints, cable termination for critical equipments and a maximum of 3 nos. on the main power cable termination - these sensed signals or out put signals from the sensors are fed to a common in put device known as Temperature data logger / scanner in a sequence corresponding to an order of arrangement of the temperature sensors output requirement of data logger /

scanner and thereby processing the said signals from sensors into a series of output signals corresponding to one sensed and appearing at the common digital display of data logger.

A reference member subjected to set temperature corresponding to a value of signal information regarding the increased temperature of the equipment monitored / scanned by temperature sensors.

A means of storing the output temperature as a reference temperature when the reference member is being set by programmable keys and output temperature which is going beyond set point which has been set by programmable keys. A means for reading the reference temperature and subtracting the reference temperature from the output temperature when the temperature which is scanned by the temperature sensors fixed to the equipment being

monitored.

A means for storing the data temperature representing the as the case may be so that equipment monitored is protected against electrical flashovers OR total failure of equipment otherwise which may cause fire hazard, explosions or any environmental disasters there of as mentioned earlier.

Figure 1 of the accompanying sketch / drawing is the block diagram of the invention and has following components.

1. Equipment monitored

2. Sensor

3. Sensor leads

4. Data logger / processor

5. Display unit

6. Feed back signal for switching off power supply to monitored equipment.

Figure 2 of the accompanying drawing shows front view of the typical monitored device for illustration, one Bus Bar joint is shown. Monitored equipment also means termination from which power is fed to the equipment through cable termination or any electrical links, bolted or any other type of joints, fuse switch ;._nits, motors, generators, flexible connection between transformer secondary between bus ducts to power control centre / motor control centres or any other joint in electrical path wherein current is flowing and failure of such entity causes electrical flashover, fire hazard, explosions or any other environmental disaster, loss of production, and process stoppages, or loss of power supply to township, industry or any other electrical power consumers.

Figure 3 of the accompanying drawing shows the temperature sensor fixed to the monitored equipment. Number of sensors / channels and corresponding type of data logger 1 scanner depends on the degree of

protection / monitoring required and criticality of the equipment. With the maximum number of sensors provided at all the joints, termination points for most critical equipment to minimum of 3 numbers at main power supply points of 3 phase equipment and one number for the single phase equipment.

Figure 4 of the accompanying drawing shows terminals of the data logger to v/hich sensor leads are connected and has the following components:

1 ,2, 3,4, 5,6 7.8 terminals for termination of sensor leads as

representation, 4 sets of terminals are shown. Data logger with printer being used in critical applications and without printer for non-critical applications.

Figure 5 of the accompanying drawing shows the first embodiment of the invention.

1. Leads of sensor

2. Sensor

Figure 6 of the accompanying drawing shows that graphs of variation of temperature when connections of the monitored device are both healthy and when loose connection has developed.

Figure 7 of the accompanying drawing shows schematic drawing explaining the apparatus of first embodiment of the invention and has the following components.

1. Equipment monitored

2. Sensor / Detector

3. Sensor leads to data scanner / logger]

Figure 8 of the accompanying drawing shows front view diagram of the apparatus of the second embodiment of the invention and has the following components :

1. Programming keys

2. Printer unit

3. Channel status display

Figure 9 of the accompanying drawing shows the rear view of the second embodiment of the invention and has the following components:

1. E - earthing terminal

2. L - supply wire terminal of for 24 - 240 V AC/DC control supply voltage.

N - neutral wire terminal

1 ,2, 3,4, 5,6. 7,8 terminals for termination of sensor leads as representation, only four sets are shown.

NO - 1 NO - 2 Relay contacts for alarm and trip. O 01/48498

Figure 10 of the accompanying drawing shows the block diagram of the Second embodiment of the invention and has the following components:

1. 24 - 240 V AC/DC control supply leads

2. Power supply and battery back up unit

3. Programmable keys

4. Sensors

5. Sensor leads

6. Data logger / scanner

7. Clock and Calender

8. Display unit

9. Printer

10. Alarm

11. Trip

12. Feed back for equipment trip

With reference to the figure - 5 of accompanying drawing an

apparatus according to the first preferred embodiment of the invention includes a plurality of sensors which are fixed on to the equipment being monitored. Sensors may be of K type. Thermo couples or PT - 100 RTD's having a temperature range of 0 - 200 ° C sensors are glass embedded or sheathed or provided with protective covering to protect the sensor against corrosion or any

other adverse conditions as the case may be. Fixing of sensors can be either bolted type, button type or adhesive type depending upon the type of / profile of monitored equipment. Any loos© connection generates abnormal quantity of heat which

can be measured in adequate quantity over the normal temperature. Also, there is a sufficient time interval in most of the cases between the beginning of loose connection to total failure of connection which will result in electrical flash over

and or failure of equipment. This duration of time varies from instantaneous to 24 hours or even more depending upon the various condition, the age of the equipment, amount of current flowing through equipment, ambient temperature and interval of time for which the equipment is put into service even after loose connection has begun. The E- FOM thus senses generated heat by plurality of sensors and is fed to microprocessor based software controlled temperature data logger for further processing and to initiate corrective action. Since response time between sensing by the sensors and corrective action initiated /

alarm given by data logger is very low and E-FOM is very fast . Figure 3 of the accompanying drawing shows one method of fixing sensor to the equipment monitored. For illustration a Bus Bar joint is shown.

With reference to figure 8 of the accompanying drawing, second embodiment of the invention includes a microprocessor based software controlled multi function data processor functioning as temperature scanner indicator, controller, alarm and trip controller and data logger with a built in single key operation for diagnostic fault finding of hardware, software, and indication devices ( EDs).

Figure 8 of the accompanying drawing represents arrangement of front panel aiongwith programmable / functional keys, 7 / 8 segment green / red LED display system, for scanned temperature, real time clock, calender

with day, month, year format. Sensor / channel number over the range and sensor failure and lead failure / open circuit protection, sensor / channel SKIP facilities, temperature set point for each sensor / channel, individual sensor / channel status indication, printer with programmable print interval setting with printing of time, sensor / channel number of scanned temperature of each sensor / channel with blue colour, printing the scanned temperature in red

colour if it is beyond set values for alarm, keys for alarm accept, reset, self driven, automatic, one touch operation for programmed diagnostic test for hardware, software and LED display.

Figure 9 of the accompanying drawing shows the rear view of the typical data processor with terminals for in put power supply, terminals for

sensor cables from individual sensor / channels to corresponding terminals and common latched relay out put contact terminals for alarm and trip signals.

Figure 10 of accompanying drawing shows Block diagram of the data logger showing function of individual modules with connected interdependent out put parameters for accurate functioning of the device.

As shown in figure 10 of the accompanying drawing data logger has

1) 24 - 240 V AC/DC control supply to data logger ;

2) Has built in rechargeable battery back up supply to run the data processor for 72 Hours in the event of failure of Auxiliary supply to the processor. Battery is continuously charged so

that battery is in perfect condition. Processor has digital clock and calender facilities having 24 hours format, with one minute least count and accuracy of +1-5 seconds/day, calender format being DD/MM YR i.e. Date, month and year. 3) It has a feather touch key board having 16 / 20 keys to enable the programme of data processor for on / off. Alarm set point, trip set point for each channel and has the facilities of individual channel alarm status display.

SEQUENCE LISTINGS

Any loose connection generates abnormal quantity of heat which can be measured in adequate quantity over the normal temperature. Also, there is a sufficient time interval in most of the cases between the beginning of loose connection to total failure of connection which will result in electrical flash over and or failure of equipment. This duration of time varies from instantaneous to 24 hours or even more depending upon the various condition, the age of the equipment, amount of current flowing through equipment, ambient temperature and interval of time for which the equipment is put into service even after loose

connection has begun. The E- FOM thus senses generated heat by plurality of sensors and is fed to microprocessor based software controlled temperature data logger for further processing and to initiate corrective action. Since response time between sensing by the sensors and corrective action initiated / alarm given by data logger is very low and E-FOM is very fast.

Signals from plurality of temperature sensors is fed to the processor. These values are compared with set values of temperature as set

by programmable keys (3) in the comparator portion of the processor (5). If the signals of sensors are more than that of set values, processor starts a set of activities after initial time delay in order to prevent false signals due to transient temperature surges, a signal is given to audible alarm unit, to record the increased temperature in red colour (10) and to trip the equipment or supply to the equipment is switched off so that the equipment monitored is protected from hazards of high temperature. Setting for alarm and trip condition depends on the maximum temperature attained by the monitored equipment when rated maximum current is flowing in the equipment when ambient temperature is highest.

Once the sensors are fixed near / on to the equipment and the equipment is put to use, the maximum temperature as recorded by recorder over a period of 24 hours taking into account the variation of ambient temperature during the hottest day is noted to this value is added a value of temperature is added so that the resultant temperature value is normal

designed, limiting allowed safe temperature as per specifications of the monitored equipment. This value is alarm setting. Similarly, a value of temperature is added so that the resultant temperature value is as per

maximum limiting temperature raise as per specifications of the monitored equipment for normal and healthy operation of the equipment. This is the trip setting.

This is a very important and critical procedure. Ideal setting varies from equipment to equipment and depends on maximum designed rated current carrying capacity of equipment taking into consideration permissible variation in power supply conditions and maximum value of ambient temperature and the actual value of current that is flowing.

Substantially as herein before described with particular reference to the accompanying drawing an apparatus titled electrical flashover monitor represented E-FOM^Λ+ is an on line automatic continuous, advance electrical O 01/48498

loose connection and flash over monitor and protection against the same in any

of the Electrical equipment(s) including the parts of equipment(s) electrical bolted joints, links, contact parts, junction, boxes cable termination in motors,

generators, power and motor control centers, cable terminations in cables, fuse switch units, flexible link connection in transformer secondaries, Bus ducts and any other equipment where it has to be guarded against high temperature, otherwise, which may cause fire hazard, explosions, or any other environmental disaster there of and has a) Plurality of 0 - 200° C 'K' type thermo couples or PT 100 RTDs temperature sensors either bolted on / button type or adhesive type arranged in a array. The number of sensors being depending on the degree of criticality of monitoring. Maximum numbers fixed at all electrical joints, terminations for critical equipment and a minimum of three sensors on the main three phase power cable terminations for the non-critical equipments.

b) Means for a reference member subjected to set temperature

corresponding to a value of signal information regarding the increased temperature of the equipment monitored / scanned by temperature sensors.

A means of storing the output temperature as a reference temperature when the reference member is being set by programmable keys and output temperature which is going beyond set point which has been set by programmable keys. O 01/48498

16

A means for reading the reference temperature and subtracting

the reference temperature from the output temperature when the temperature which is scanned by temperature sensors fixed to the equipment being

monitored.

A means for storing the data temperature representing the information related to the different temperature values as sensed by temperature sensors fixed to the equipment monitored.

A means for converting this output data to drive latched relay so that contacts from relay is used to initiate an audible alarm / LED display and switching off supply to the monitored equipment as the case may be so that equipment monitored is protected against electrical flashovers total failure of equipment otherwise which may cause fire hazard, explosions or any environmental disasters there of.

ELECTRIC FLASHOVER MONITOR E.FOM*⁺ is an apparatus wherein an on line automatic continuous advance, electrical loose connection and flash

over is detected and prevented the same in any of the Electrical equipments) including the parts of equipment(s) electrical bolted joints, links, contact parts, junction, boxes cable termination in motors, generators, power and motor control centers, cable terminations in cables, fuse switch units, flexible link

connection in transformer secondaries, bus ducts and any other equipment which it has to be guarded against high temperature, otherwise, which may cause fire hazard, explosions, or any other environmental disaster there of.

Claims

1. E - FOM ⁺ can effectively used to prevent flashovers / failures / damages to fuse switch / switch fuse units, power control centers, motor control centers, circuit breaker chambers, Bus ducts, Junction boxes, current transformer chambers, motor terminal boxes cable termination at motor control centers, power control centers, power distribution and all types of transformers, including current and potential transformers, flexible connection between

transformers to Bus ducts, Bus ducts to power control centers / motor control centers between Bus ducts and all other electrical equipment including parts of equipment where failure due to increase in flash over resulting in damages to equipment, environment explosions, loss of production due to production / process stoppages, fire hazards and any other damages leading to loss of human life, destruction of property, and environmental disaster.

2. E - FOM*⁺ can be used for automatic on line continuous recording / monitoring of Tightness of / Healthiness of electrical connections, joints, male- female joints, plug and socket joints and all types of electrical connections, terminations.

3. E - FOM*⁺ can be used to record / monitor thermal profile of electrical joints in any electrical equipment or devices including parts of equipment and any other non-electrical equipment, wherein limiting the temperature raise of the monitored equipment within the designed continuous temperature value is of utmost importance for smooth and accurate functioning of the monitored equipment.

4. E - FOM*⁺ is Accurate, reliable, automatic, maintenance free and economical as it does not require deployment of labour and can be used in un-manned sub-stations and equipments including mining and space applications for accurate monitoring of electrical terminations and thermal profile of the same.

5. E - FOM^x+ has cutting edge novelty with add on features and can be readily used in most of the equipment which are in service without any

modification of design or structural changes to the equipments, and also it does not alter, affect the normal performance of the monitored equipment.