BACKGROUND OF THE INVENTION In large electric power consuming communities such as schools, buildings, apartment complexes, and factories, there are their own reception power transforming facilities, so that the necessary electric power can be obtained.

In such communal power facilities, there are included transformers, switching devices and safety devices, so that a high voltage can be stepped down to a proper low voltage.

In the conventional reception power transforming facilities, the transformers together with the peripheral switching devices and metering devices are disposed in a planar form. Further, between the transformers and the peripheral devices, sufficient separation distances are provided. The result is that the installation area becomes large. Further, a great difficulty is encountered in transporting the large apparatuses.

Further, in the conventional reception power

transforming apparatuses, in order to prevent any accident caused by a leakage of the high voltage power, the case consists of multiple layers, with the result that the total weight is increased.

Such a bulk increase and a weight increase not only cause an increase in the installation time period, but also adds to the installation cost.

Further, in the conventional reception power transforming apparatuses, no much consideration was given to the noises and to the harmful electromagnetic waves.

Therefore, the transforming apparatuses are disposed at places remote from the power users, and consequently, a considerable amount of power is lost. However, if the reception power transforming apparatus is installed closely to the power user to avoid the mentioned loss, then a measure is required to shield the noises and the harmful electromagnetic waves. Accordingly, an additional expense is incurred.

The recent target in designing and manufacturing the reception power transforming apparatus is the reduction of the bulk and weight of the facility for alleviating the burden of the installation task. Further, the target is focusing on the safety and the prevention of a power leakage.

SUMMARY OF THE INVENTION The present invention is intended to overcome the above described disadvantages of the conventional techniques.

Therefore it is an object of the present invention to provide a package type reception power transforming apparatus which steps down a high voltage of 6,600-22,900 V to a low voltage of 220-380 V to supply the low voltage to buildings and factories, and in which reception power distribution devices and a power monitor-controller together with a high efficiency transformer are packed into a single box, thereby miniaturizing the package to reduce

the installation area and making it possible to carry out a manless operation.

In achieving the above object, the package type reception power transforming apparatus is characterized in that: a case is divided into a plurality of compartments; an ASS (automatic section switch) (of a high voltage inletting part), a lightning arrest, a line breaker, a power metering device, a high voltage transformer, and a central control breaker are disposed in the respective compartments in a power flow order and in a multi-layer structure; a high voltage side and a low voltage side are separated but unitized; and a forcible blow cooling system is applied to the transformer, whereby the reception power transforming apparatus is made to have a reduced bulk and a light weight owing to an improved power transformation efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS The above object and other advantages of the present invention will become more apparent by describing in detail the preferred embodiment of the present invention with reference to the attached drawings in which: FIG. 1 is a circuit diagram showing the constitution of the circuits of the package type reception power transforming apparatus according to the present invention; FIG. 2 is a perspective view showing the internal structure of the package type reception power transforming apparatus according to the present invention; FIG. 3 is a frontal view showing the high voltage side of the package type reception power transforming apparatus according to the present invention; FIG. 4 is a frontal view showing the low voltage side of the package type reception power transforming apparatus according to the present invention ; FIG. 5 is a side view of the package type reception power transforming apparatus according to the present invention;

FIG. 6 is a side sectional view showing the internal structure of the package type reception power transforming apparatus according to the present invention; FIG. 7 illustrates a cooling device for the high voltage transformer according to the present invention; FIG. 8 is a frontal view of a second embodiment of the high voltage transformer of the apparatus according to the present invention; FIG. 9 is a plan view of the second embodiment of the high voltage transformer of the apparatus according to the present invention; FIG. 10 is a plan view of a radiating part provided in the second embodiment of the high voltage transformer of the apparatus according to the present invention; FIG. 11 is a frontal view of the radiating part provided in the second embodiment of the high voltage transformer of the apparatus according to the present invention; FIG. 12 is a side view of the radiating part provided in the second embodiment of the high voltage transformer of the apparatus according to the present invention; FIG. 13 illustrates the attachment of a temperature tape for sensing the radiated heat under a connection defect of a low voltage outputting bus bar of the apparatus according to the present invention; FIG. 14 illustrates the flow of the cooling gas showing the function of the radiating vane provided in the radiating part of the second embodiment of the high voltage transformer of the apparatus according to the present invention; FIG. 15 is a partial perspective view showing the installation structure of a cooling fan of the apparatus according to the present invention; FIG. 16 illustrates the circuit connections to the peripheral devices for carrying out the functions of an intelligent power monitor-controller according to the present invention; and

FIG. 17 is a flow chart showing the safety control procedure of a controller of the power monitor-controller according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing the constitution of the circuits of the package type reception power transforming apparatus according to the present invention.

As shown in this drawing, a 3-phase 22,900V high voltage which is supplied through a high voltage transmission line 34 into the package type reception power transforming apparatus according to the present invention passes through an ASS (automatic section switch) 11 and then through a high voltage transmission line 48 to be supplied to a lightning arrest 13 and a cold current fuse 12, the lightning arrest 13 being grounded.

A set of the cold current fuses 12 consists of three pieces, and each of them is installed on each RST line of the 3-phase input lines.

On each of the 3-phase lines which have passed through the cold current fuses 12, there is installed an MOF (metering outfit) 14, to measure the voltage and current used so as to measure the used amount of power. The voltage and current values which are detected by the MOF 14 are supplied to a volt meter and an ammeter which are installed on a power meter 15.

Meanwhile, the high voltage which has passed through the cold current fuses 12 is supplied through a high voltage transmission line 65 into a A-connected high voltage input terminal 44 of a high voltage transformer 16, so that a low voltage would be outputted through a secondary side low voltage terminal from a Y-connected circuit. The low voltage which appears in the secondary low voltage terminal 43 of the high voltage transformer 16 is supplied through 4-terminal MCCB (mold-cased circuit breakers) 19 and 22 to a load.

The secondary side low voltage output terminal of the

high voltage transformer 16 is connected through a 3- terminal MCCB 17 to a capacitor 18 for improving the power factor.

A power monitor-controller 20 is connected to the secondary voltage value of the high voltage transformer which is connected through a fuse to the MCCB 19. The controller 20 is further connected to the load current value (for each phase) of a CT (current transformer) 21 which is installed at the output side of the MCCB 19.

FIGs. 2 to 6 illustrate the structure of the package type reception power transforming apparatus according to the present invention. FIG. 2 is a perspective view showing the internal structure of the package type reception power transforming apparatus according to the present invention. FIG. 3 is a frontal view showing the high voltage side of the package type reception power transforming apparatus according to the present invention.

FIG. 4 is a frontal view showing the low voltage side of the package type reception power transforming apparatus according to the present invention. FIG. 5 is a side view of the package type reception power transforming apparatus according to the present invention. FIG. 6 is a side section view showing the internal structure of the package type reception power transforming apparatus according to the present invention.

Referring to these drawings, the 6,600-22,900V high voltage which is incoming through a high voltage inletting part 28 and through the high voltage transmission line 34 is supplied into a high voltage input terminal 39 of the ASS 11 which has an ASS lever 38. The high voltage which appears in a high voltage drawing terminal of the ASS 11 is supplied through a high voltage transmission line 48 to a lightning arrest 13 and to the cold current fuse 12. The high voltage which has passed through the fuse 12 is supplied through a high voltage transmission line 49 to an MOF (metering outfit) 14. The high voltage which is drawn from the MOF 14 through a high voltage transmission line is

supplied to a high voltage terminal 44 of the high voltage transformer 16.

In front of the cold current fuses 12 through which the high voltage power flows, a transparent safety plate 32 is installed, so that people are made not to approach the transforming facility. Further, between the three cold current fuses 12, there are installed arc shielding plates 30.

On the ceiling of a case 24 along which the high voltage transmission lie passes, there is installed a grounding net 41-1 for picking up the arcs due to the power leakages, so as to ground them. This grounding net 41-1 consists of metal wires in a network form, in such a manner that numerous pockmarks are formed. In order to reduce the possibility of accidents, this grounding net 41-1 is grounded through a grounding box 27 independently from the grounding wire of the case 24.

Further, if a power leakage occurs at the high voltage transmission lines 49 and 65 which connect the high voltage terminals of the high voltage transformer 16 and the metering current transformer 21, then the leakage currents are quickly picked up to be grounded. For this purpose, a grounding net 41 is installed separated from the inner wall of the case 24 and in parallel with the wall, and this grounding net 41 is connected to a grounding terminal box 27 through a separate wire like the grounding net 41-1.

The grounding net 41 has also numerous pockmarks, and therefore, the arcs can be easily picked up. It also has network wires to reduce the bulk.

The 380 or 220V low voltage which appears on the low voltage terminal 43 of the secondary side of the high voltage transformer 16 is supplied through a bus bar 67 to a central control breaker (not shown in the drawings) of the low voltage part by being separated by a high voltage shielding wall 42.

Further, a high voltage side door 32 and a low

voltage side door 35 are installed respectively at the high voltage side and the low voltage side of the package type reception power transforming apparatus. The two doors are respectively provided with a see-through window 33 or 36.

Particularly, the see-through window 33 of the high voltage side door 32 is provided with a metal mesh 37 for absorbing the electromagnetic waves and the arcing currents to bypass them to the ground.

In the high voltage side, there is installed a high voltage side lamp to illuminate the interior when the high voltage side door 32 is open. In the same manner, the low voltage side door 35 is provided with a low voltage side lamp 24 to illuminate the interior when the door is open.

As shown in FIG. 5, on the side walls of the case 24, there are provided see-through windows 25 and 26 for monitoring the operation status of the ASS 11 from the outside, and for monitoring the operation status of the high voltage transformer from the outside. Beneath the case 24, there is installed a grounding terminal box 27.

FIG. 7 illustrates a cooling device for the high voltage transformer according to the present invention. As shown in this drawing, a low voltage terminal 43 is formed on the top of a high voltage transformer 15, and a high voltage terminal 44 is formed on a side upper portion of this transformer 16, while an oil injecting hole 45 is formed on the top of the transformer 16, the transformer 16 being filled with oil.

Further, in order to radiate the heat generated from the transformer, a plurality of heat radiating plates 46 are stacked around the transformer 16 with gaps between the plates 46.

FIG. 8 is a frontal view of a second embodiment of the high voltage transformer of the apparatus according to the present invention. FIG. 9 is a plan view of the apparatus of FIG. 8.

Referring to these drawings, a plurality of heat radiating plates 61 are stacked with gaps between them

around the transformer 50 so as to prevent the rise of the oil temperature within the oil tank 59.

In the transformer having the heat radiating plates 61, the transformer case 55 forms a sealed structure and an air path, while a heat insulating material 60 and a lid 54 are provided.

Further, auxiliary cooling plates 63 are disposed between the heat radiating plates 61.

Further, a gasket 62 is disposed between the oil tank 59 and the lid 54 to prevent the leakage of oil.

A ventilation hole 56 is formed on a lower side wall of the transformer case 55, and an air blowing hole 57 is formed on the bottom of the transformer. Inside the air blowing hole 57, there are formed a plurality of nozzles 58 along the bottom of the transformer case.

On the top of the oil tank 59 of the transformer 50, there are installed three high voltage terminals 51, so that high voltage power transmission lines can be connected to them based on A connections. Four low voltage terminals 53 are installed also on the top of the transformer case, so that power can be supplied through switch devices to a load based on Y connections.

FIGs. 10 to 12 are a plan view, a frontal view and a side view of a radiating part provided in the second embodiment of the high voltage transformer of the apparatus according to the present invention.

Referring to these drawings, a plurality of heat radiating plates 61 of the transformer 50 are formed in a continuous parallel form, while a plurality of auxiliary plates 63 are disposed between the heat radiating plates 61 so as to form flow spaces for the cooling air streams.

In order to improve the cooling efficiency by scattering the cooling air, the auxiliary cooling plates 63 are partly cut at different points to form vanes 64 as shown in FIG. 14, and the inclination directions of the vanes 64 are made to be opposite alternately at each layer.

FIG. 13 illustrates the attachment of a temperature

tape for sensing the radiated heat under a connection defect of a low voltage outputting bus bar of the apparatus according to the present invention. That is, a temperature tape 68 is attached on a connecting portion 67 of the bus bar 66 of a low voltage line, so that the connection status can be visually confirmed when the low voltage of the secondary side of the transformer is connected through a switch to a load.

FIG. 15 is a partial perspective view showing the installation structure of a cooling fan of the apparatus according to the present invention. A pair of cooling tray 69 with cooling fans 70 formed therein are inserted into insertion holes 29 which is originally intended for receiving the arms of a fork lift truck.

FIG. 16 illustrates the circuit connections to the peripheral devices for carrying out the functions of an intelligent power monitor-controller according to the present invention.

Referring to these drawings, a power monitor- controller 20 receives the system analysis source data such as the transformer temperature detection signals, the peripheral temperature detection signals, and the door open contact signals. Further, it receives the voltage and current values of the respective phases of the primary and secondary sides so as to control the peak power of the load side, the power factor, the lack of equilibrium of the transformer, and any skipping of the phase.

This power monitor-controller 20 includes a first peak expansion unit 71 and a relay unit 72 to control the load.

It further includes a second peak expansion unit 73 and a relay unit 74 to control the capacitors. It still further includes an input/output unit 75 and a relay unit 76 to control the breaker load operating circuit.

The control data which have been monitored and processed by the power monitor-controller 20 are transmitted to a computer 77 to be stored there and to be printed out through a printer 78.

The control data which have been monitored and processed by the power monitor-controller 20 can be transmitted through a communication modem 79 and a converter 80 to a local computer 81 which has a printer 82.

Further, they can be transmitted to a host computer 83 which has a graphic board 84 and a printer 85. Still further, they can be transmitted through a faxmodem 86 to a remote telephone 87 or to a facsimile 88.

The apparatus of the present invention constituted as above will now be described on its operations.

When a 22,900V high voltage is supplied, this high voltage passes through a high voltage transmission line 34 to be inputted into a high voltage input terminal 39 of the ASS 11 which has an ASS actuation lever 38. The ASS 11 selects one of a spare line (or an off-line) and a high voltage input line by the help of the ASS actuation lever.

The high voltage of the high voltage line which has been selected by the ASS actuation lever 38 appears on the high voltage drawing terminal 40. This high voltage is supplied through the high voltage transmission line 48 to the lightning arrest 13 and the cold current fuse 12.

That is, the ASS 11 supplies the high voltage through the grounded lightning arrest 13 and the cold current fuse 12 to the high voltage transformer 16 and the metering current transformer 21.

The cold current fuse 12 is a silicon fuse, because silicon is filled in the fuse box. Therefore, this fuse exerts a high resistance against the generation of arc, so that an accident current can be blocked in a short period of time.

A set of the lightning arrest 13 consists of 3 pieces to be disposed on every line of the 3-phase lines, and the lightning arrests 13 are disposed within an upper compartment. If a green ultra-high voltage of lightning is supplied, the lightning arrest 13 quickly bypasses it to the ground, thereby protecting the reception power transforming apparatus from the lightning.

The high voltage transmission line 48 which passes through the cold current fuse 12 and the lightning arrest 13 maintains a sufficient gap from the ceiling of the case 24. However, if an arc is generated due to a power leakage, the arc current is picked up by the grounding net 41-1 before the arc current reach the case 24, so that an accident can be prevented.

Particularly, the grounding net 41-1 consists of a metal wire network, and therefore, it is considerably lighter than a metal plate. Further, There are numerous pockmarks, and therefore, any leakage current can be easily picked up to be bypassed to the ground.

The MOF (metering outfit) 14 supplies the transformed voltage and current to a voltmeter and an ammeter of a meter box 15.

The meter box 15 accommodates gauges such as a power meter and the like.

Meanwhile, if a 3-phase A-connected high voltage which has passed through the cold current fuse 12 and the high voltage transmission lines 49 and 65 is supplied to the high voltage terminal 44 of the high voltage transformer 16, then a Y-connected 380/220V low voltage is induced in the secondary side of the transformer 16 to ultimately appear on the low voltage terminal 43.

This low voltage is transferred from the low voltage terminal 43 through the bus bar 67 to an output panel on which various meters and switches are disposed. Within the package, the output panel is isolated from the high voltage transformer by the high voltage shielding wall 42.

The low voltage terminal of the transformer 16 is connected through the MCCB 17 to the capacitors 18 for phase-leading for each phase. Therefore, the power factor is improved so that the power consumption efficiency would be improved. The phase-leading capacitors 18 are accommodated within different compartments, and thus, if an accident occurs at one capacitor, the accident is prevented from being propagated to the other compartments.

Meanwhile, a high voltage transformer is classified into an oil-filled type and an molded type. The transformer of the present invention is an oil-filled type, and therefore, the interior of the transformer is filled with oil. The heat which is generated during the operation of the transformer is dissipated through the plurality of the heat radiating plates 46 and the cooling fans 47.

This forced cooling improves the operating efficiency of the transformer. That is, in the case of a molded type transformer, the rated capacity can be improved up to 30- 50%, while in the case of the oil-filled type transformer, the rated capacity can be improved up to 10- 20%.

Thus power squandering can be prevented, and with the same rated capacity, the size of the transformer can be reduced.

Particularly, the transformer installation portion is intensively cooled, so that a more improved cooling efficiency can be obtained compared with the case of cooling the total bulk of the power transforming apparatus.

FIGs. 8 and 9 illustrate a second embodiment of the high voltage transformer of the apparatus according to the present invention.

A cooling air is sent through the air blowing hole 57 of the bottom of the case 55, so that air would be injected through the plurality of the nozzles 58, and that air would flow from the bottom of the transformer upward.

The cooling air which has been introduced through nozzles 58 flows upward through the heat radiating plates within the transformer to absorb heat. Then the air flows along discharge passage which is formed on the case 55 to be discharged through the discharge hole 56.

The heat insulating material 60 protects the heat dissipating function of the heat radiating plates 61, when the cooling air is discharged after being warmed by being heated by absorbing the heat from the heat radiating plates 61.

As shown in FIGs. 10 to 12, the specific structure of the heat radiating plates 61 is such that a plurality of heat radiating plates 61 are disposed in the peripheral region within the transformer case, and a plurality of auxiliary cooling plates 63 are disposed between the heat radiating plates 61 so as to form flow paths for the cooling air.

In order to improve the cooling efficiency by scattering the cooling air, the auxiliary cooling plates 63 are partly cut up at different points to form vanes 64 as shown in FIG. 14, and the inclination directions of the vanes 64 are made to be opposite alternately at each layer, in such a manner that they should lie in a zig-zag form.

Thus when the cooling air passes through auxiliary cooling plates, the cooling air is scattered.

Such a scattering phenomenon improves the cooling efficiency of the heat radiating plates, thereby ultimately improving the efficiency of the transformer.

FIG. 13 illustrates the attachment of a temperature tape for sensing the radiated heat under a connection defect of a low voltage outputting bus bar of the apparatus according to the present invention. That is, a temperature tape 68 is attached on a connecting portion 67 of the bus bar 66 of a low voltage line, so that the connection status can be visually confirmed when the low voltage of the secondary side of the transformer is connected through a switch to a load. If the connection status of the secondary side output terminal is defective, and so if heat is generated from it, then the color of the temperature tape 68 is changed.

The color change of the temperature tape can be easily observed from the outside through the see-through window, and therefore, any abnormality of the connection status of the output terminal can be checked even without opening the door.

Meanwhile, the package type reception power transforming apparatus according to the present invention

can be transported and installed only by heavy duty vehicles. Therefore, the transforming apparatus is provided with a pair of holes 29 which are for receiving the arms of a fork lift truck. Therefore, the power transforming apparatus according to the present invention can be easily transported and installed by using a fork lift truck.

After the installation of the power transforming apparatus by using a fork lift truck, a pair of cooling fan trays 69 are inserted into the holes 29 which have been used for receiving the arms of a fork lift truck. Cooling fans 70 are formed in the cooling fan tray 69, and therefore, the interior of the package, particularly the transformer can be efficiently cooled.

FIG. 16 illustrates the circuit connections to the peripheral devices for carrying out the functions of an intelligent power monitor-controller 20 according to the present invention. The controller 20 checks, records and remote-controls the supply of the secondary power to the load.

Referring to this drawing, a power monitor-controller 20 receives the system analysis source data such as the transformer temperature detection signals, the peripheral temperature detection signals, and the door open contact signals. Further, it receives the voltage and current values of the respective phases of the primary and secondary sides so as to control the peak power of the load side, the power factor, the lack of equilibrium of the transformer, and any skipping of the phase.

This power monitor-controller 20 includes a first peak expansion unit 71 and a relay unit 72 to control the load.

It further includes a second peak expansion unit 73 and a relay unit 74 to control the capacitors. It still further includes an input/output unit 75 and a relay unit 76 to control the breaker load operating circuit.

The control data which have been monitored and processed by the power monitor-controller 20 are

transmitted to a computer 77 to be stored there and to be printed out through a printer 78.

The control data which have been monitored and processed by the power monitor-controller 20 can be transmitted through a communication modem 79 and a converter 80 to a local computer 81 which has a printer 82.

Further, they can be transmitted to a host computer 83 which has a graphic board 84 and a printer 85.

Still further, they can be transmitted through a faxmodem 86 to a remote telephone 87 or to a facsimile 88.

FIG. 17 is a flow chart showing the safety control procedure of a controller of the power monitor-controller according to the present invention.

Referring to this drawing, if the system power of the reception power transforming apparatus is turned on, then the controllers of the power monitor-controller simultaneously carry out a transformer temperature detection, a system internal temperature detection, a power source voltage detection, a door open detection and an external impact detection.

In the transformer temperature detection procedure, the transformer temperature is detected to judge as to whether the detected present temperature has reached a first set temperature, e. g., 65°C. If the present temperature has reached the first set temperature, then the controller activates the cooling fans to cool down the transformer.

After the activation of the cooling fans, if the detected transformer temperature has reached, for example, 75°C after exceeding the first set temperature, then the controller activates a warning lamp and an alarm. Thus it is notified that the heat generating status of the transformer is very high.

Thereafter, if the detected transformer temperature reaches, for example, 90°C, i. e., a third set temperature, then the controller activates the ASS to block the inletting of the high voltage.

In the system internal temperature detection procedure, the system internal temperature is detected to judge as to whether the detected present temperature has reached a first set temperature, e. g., 60°C. If the present temperature has not reached the first set temperature, then a judgment is made as to whether a second set temperature, e. g.,-10°C has been reached.

If the detected present temperature is below-10°C, then a heater is activated to raise the system internal temperature.

On the other hand, if the detected present temperature has exceeded the first set temperature, then a warning lamp and an alarm are activated to notify the fact to the manager. If the system internal temperature reaches a third set temperature, e. g., 80°C, then the ASS is activated to block the inletting of the high voltage.

In the power source voltage detecting procedure, the incoming high voltage and the outgoing low voltage are checked, and the active power and the reactive power are calculated. Further, the fluctuation width of the power frequency is checked, and the supplying and blocking time information is also checked.

In the door open detection procedure, first the activeness of the high voltage side limit switch is judged.

If the limit switch of the high voltage side door is active, then the controller lights the internal illuminating lamp, activates the ASS, and activates the warning lamp and the alarm. However, if the high voltage side door is not open, then it is judged as to whether the limit switch of the low voltage side door is active. If thus the low voltage side door is open, the internal illuminating lamp of the low voltage side is lighted, and the warning lamp and the alarm are activated.

In the external impact detecting procedure, if an impact with more than the rated value is imposed on the impact sensor, then an impact detecting switch is

activated. If such an impact detection occurs, the warning lamp and the alarm are activated, and the ASS is activated to block the inletting of the high voltage.

When the transformer temperature detection, the system internal temperature detection, the power source voltage detection, the door open detection or the external impact detection is carried out, the relevant information is stored in the internal memory of the system. Further, the information is transferred to the power monitor- controller 20, so that an emergency transmission program can be executed, and that the occurrence of an accident can be notified to a remote place through a facsimile.

Thus the attention of the manager can be called under an emergency mode, and the accident information can be displayed on a digital display.

According to the present invention as described above, the high voltage transformer, the ASS and the like are accommodated within a single package in the form of a multi-layer structure. Thus it contributes to the reduction of the bulk of the package, and facilitates the transportation and reduces the installation time.

Further, there are provided grounding nets, so that the arcing current can be quickly picked up and grounded through a cable before the arcing current reaches the case, thereby making it possible to prevent accidents.

Further, in the present invention, the cooling efficiency is improved, and therefore, the power transforming efficiency is improved, with the ultimate result that the bulk of the power transforming apparatus is reduced.

Further, safety checking are comprehensively carried out so that the checked results can be transmitted from the power monitor-controller to a remote manager or to a host computer. Therefore, a plurality of power transforming apparatuses can be centrally controlled through a web type net work.