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1. (WO2019002222) SWITCHGEAR OR CONTROLGEAR WITH UNMANNED OPERATION AND MAINTENANCE, AND METHOD OF OPERATING THE SAME
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Switchgear or controlgear with unmanned operation and maintenance, and method of operating the same

The invention relates to a switchgear or controlgear with unmanned operation and maintenance, and method of operating the same, according to the preamble of claim 1 and 2.

Background

Switchgears or controlgear with unmanned operation and maintenance ensures the same personnel safety levels as current generation of switchgear or controlgear by excluding human operators from the operation and maintenance processes and by the outer enclosure. However, due to open internal space without segregations 22 and embedded robotic system 21 new requirements to equipment safety assurance must be defined. Current common practice of protection provided by enclosure would not be beneficial inside switchgear or controlgear with unmanned operation and maintenance, therefore other means to ensure equipment safety are required.

Object of the invention

So the object of the invention is, to enhance safety in operation of unmanned switchgear operation.

Invention

The internal segregation in current design of switchgear or controlgear serve primarily personnel safety purpose and secondarily equipment safety purpose by preventing foreign solid objects entering potentially hazardeous areas with live primary circuits. The degrees of protection provided by enclosure (Code IP) are described in I EC 60529 standard.

So considering what was said in the object of the invention,

the equipment safety system of switchgear and controlgear with unmanned operation and maintenance consists in its action radius of a division of the acting area in the internal switchgear or controlgear space into virtual zones, and each action in such a zone is calculated predictively as a kind of a micro simulation, in which actual sensor data are considered, before the intended action will be really triggered.

That is shown in figure 2.

So by the invention great risks in operating a switch- or controlgear are overcome.

In unmanned switchgear or controlgear system enegized primary circuits are in the same space with moving robotic system. The robotic system represents foreign solid object moving near the enegized circuits and the robotic system has to ensure it does not cause equipment faults.

According to a method of operating such a switch- or controlgear, the invention is, that an equipment safety system of switchgear and controlgear with unmanned operation and maintenance consists in its steering and control system of means for calculating the action radius of a robot system, wherein the acting area in the internal switchgear or controlgear space is divided into virtual zones, and each action in such a zone is precalculated predictively as a kind of a micro simulation, in which actual sensor data are considered, before the intended action will be really triggered.

In a further advantageous embodiment, the complete action area is divided and structured automatically under consideration of the following conditions:

detection of a main busbars zone, which contain all horizontal busbars and T-offs circuits of one busbar section up to all points of disconnection,

and/or

detection of each switch-disconnector, which have own zone including the moving contact of the switch- disconnector when in earthed position and all the circuits up to the next point of opening like circuit breaker main contacts,

and/or

each primary circuit continuing from the circuit breaker main contacts, which have own zone covering the circuits up to the next point of disconnection or to the point where the circuits go out of the enclosure, and/or

the zones containing auxiliary circuits and mechanisms, limited by metalic earthed segregation of the auxiliary circuit space from the primary circuit space.

An embodiment of the invention is shown in the drawing.

Figure 1 : Example crossection of switchgear or controlgear with unmanned operation and maintenance

Figure 2: Example of dividing the internal space to virtual zones

Figure 3: 3D view of switchgear or controlgear segregation to virtual zones

The virtual zones are main busbar zone 40, disconnector switch zone 41 , circuit breaker auxiliary zone 42, feeder primary circuits zone 43 and default secured zone 44. One common default sacured zone 44 and one common main busbar zone 40 can exist across the whole section of feeders with no limits in z-axis, like shown in figure. 3 , while the disconnector switches zones 41 a, 41 b, 41 c, circuit breakers auxiliary zones 42a, 42b, 42c, ... and feeders primary circuits zones 43a, 43b, 43c, ... are limited by virtual boundaries in z-axis and are separated for each particular feeder, see Fig.3.

In general, the zones boundaries shall be defined in such way, that the robotic system cannot get to shorter than safe distance from energized circuits of a zone that is not secured when operating within zones that are secured. The safe distance depends on the primary circuits nominal voltage (Un), voltage withstand level (Ud) and basic insulation level (Up) and distances from current safe clearance and creepage distance practice shall be applicable here.

Other zones layouts than shown on the examples Fig. 2 and Fig.3 are possible, the zones should always respect physical layout of the primary circuits and the switching devices location in the circuits. The zone creation rules in general shall be following:

- The main busbars zone shall contain all horizontal busbars and T-offs circuits of one busbar section up to all points of disconnection.

- Each switch-disconnector shall have own zone including the moving

contact of the switch- disconnector when in earthed position and all the circuits up to the next point of opening (for example circuit breaker main contacts).

- Each primary circuit continuing from the circuit breaker main contacts shall have own zone covering the circuits up to the next point of disconnection or to the point where the circuits go out of the enclosure. - The zones containing auxiliary circuits and mechanisms should be limited by metalic earthed segregation of the auxiliary circuit space from the primary circuit space

Each virtual zone containig primary circuits 40, 41 and 43 can have one of following statii:

1 . zone energized: when primary circuits of corresponting zone are

energized

2. zone de-energized: primary circuits of corresponding zone are de- energized but not earthed

3. zone secured: primary circuits of corresponding zone are de-energized and earthed

4. zone locked in secured: zone is secured and any status change is locked as the robot is operating in the zone

Robotic system movement limitations in zones containing primary circuits then depend on virtual zone status:

1 . zone secured: robotic arm and tooling can physicaly interact with circuits inside the zone, before robot access secured zone, the zone status is switched to Locked in secured and when the inteaction finishes the zone status is switched back to secured

2. Zone de-energized: robotic arm and tooling must respect the clearance and creepage distance between de-energized circuits and robotic arm - only insulated tools can be used for interaction in de-energized zone

3. zone energized: robot arm and tooling cannot enter the zone

The status of the primary circuits (energized/de-energized/earthed) in each virtual zone can be learned from signals received from the limit switches associated with the switching devices (switch-disconnectors and circuit breakers) or can be learned by visual confirmation of the device status using optical camera and automatic image recognition algorithms inside the

switchgear or controlgear. The switching device status confirmation system can be made redundant by combining both above mentioned methods.

Confirmation of the primary circuits de-energized status can be obtained by real time voltage detection by electrical field measurement located on the robotic manipulator wrist. A voltage proximity detector with directional discrimination is preferred due to complicated electrical field conditions in the switchgear or controlgear internal space.

Detection of rapid increase of electrical field strenght while approaching primary circuits or even simple detection of strong electrical field in proximity to the conductors should cause immediate stop of the robot movement in the direction towards the primary circuits followed by retraction and reevaluation of the circuits status.

In alternative design to the one described in previous section, the voltage detection by electrical field measurement device or voltage detection contact tester is included into the robot tooling. Robot then start equipment interrogation with voltage check routine using the voltage check device from his toolbox as the first step before interacting with the primary circuits in the virtual zone.

The virtual zones containing auxiliary circuits and mechanisms 42 can have following statii:

1 . zone energized or charged: when auxiliary circuits in corresponting zone are energized or the auxiliary mechanisms are charged

2. zone secured: auxiliary circuits in corresponding zone are de-energized and auxiliary mechanisms are discharged

3. Zone locked in secured: zone is secured and any status change is locked as the robot is operating in the zone

Robotic system movement limitations in zones containing auxiliary circuits then depend on virtual zone status:

1 . zone secured: robotic arm and tooling can physicaly interact with circuits and mechanisms inside the zone, before robot access secured zone, the zone status is switched to locked in secured and when the interaction finishes the zone status is switched back to secured

2. zone energized or charged: robotic arm and tooling interaction is limited to replacement of pre-defined parts, that are built in such way, that no dangerous contact with energized circuits or charged mechanisms can happen