Voltage measurement device with an insulating body
View Patent ↗A voltage measurement device includes an insulating body, for the use in medium- or high-voltage equipment or switchgears The insulating body includes an impedance divider having at least one high voltage impedance and at least one low voltage impedance in series, and with shielding electrodes. In order to optimize the circuit design for voltage measurement design in a given application and prevent the risk of malfunction when the same device it is used in multiple applications or at severe environmental or operating conditions, the device includes at least one high-voltage shielding electrode and/or at least one low-voltage shielding electrode which dimensions together establish a physical length of the impedance divider. The shielding electrodes surround the high and/or low voltage impedances, which provide a specified voltage division ratio and which are located inside or outside of the insulating body. An output of the impedance divider is connected to a shielded cable.
1. A voltage measurement device with an insulating body, for use in medium- or high-voltage equipment or switchgears, comprising:
an impedance divider including at least one high-voltage impedance, at least one low-voltage impedance, and at least two shielding electrodes,
wherein the at least one high-voltage impedance and the at least one low-voltage impedance are connected in series, provide a specified voltage division ratio, and together establish a physical length of the impedance divider,
wherein the shielding electrodes include at least one high voltage shielding electrode and at least one low voltage shielding electrode,
wherein the shielding electrodes are arranged to surround the at least one high-voltage impedance and the at least one low-voltage impedance,
wherein an output of the impedance divider is connected to a shielded cable, and
wherein the shielding electrodes are longer than a physical length of the high-voltage impedance and the low-voltage impedance surrounded by the shielding electrodes, such that a length of the high voltage shielding electrode is longer than a length of the high-voltage impedance and a length of the low voltage shielding electrode is longer than a length of the low-voltage impedance in order to sufficiently shield the whole high-voltage impedance and low-voltage impedance from external influences.
2. The voltage measurement device according to claim 1 , wherein the shielding electrodes distribute the electric field and reduce electric field stress either inside or outside of the said device based on a location of the at least one high-voltage impedance and the at least one low-voltage impedance.
3. The voltage measurement device according to claim 1 , wherein the at least one high-voltage impedance and the at least one low-voltage impedance are located inside the insulating body.
4. The voltage measurement device according to claim 1 , wherein the shielding electrodes are in ring or bell shapes, having roundings at the edges with radius of at least 0.5 mm.
5. The voltage measurement device according to claim 1 , wherein the shielding electrodes are located at least 1 mm internally from a surface of the insulating body.
6. The voltage measurement device according to claim 1 , wherein a distance of the shielding electrodes from the impedance divider is larger than a distance that maintains the dielectric integrity of a material forming the insulating body for a voltage level under which the impedances are operating.
7. The voltage measurement device according to claim 1 , wherein a distance between the shielding electrodes is larger than a distance that maintains the dielectric integrity of a material forming the insulating body for a voltage level which occurs in an area between said shielding electrodes.
8. The voltage measurement device according to claim 1 , wherein the impedance divider is a resistive divider, a capacitive divider, or a combination thereof.
9. The voltage measurement device according to claim 1 , wherein the shielded cable is a twisted pair or a double shielded cable for achieving an electric and magnetic field immunity for output from the device.
10. The voltage measurement device according to claim 1 , wherein the shielded cable is a coaxial cable having a performance that reduces costs of the device as a whole.
11. The voltage measuring device according to claim 1 , wherein the insulating body has at least one of a shape and a functionality of a post insulator, bushing, or cable plug.
12. The voltage measuring device according to claim 1 , wherein the insulating body is a stand-alone voltage measurement module that is to be integrated into other devices.