Univ.-Prof. Dr.-Ing. Frank Berger
Head of Electrical Apparatus and Switchgear Group
+49 3677 69-2834
Kirchhoffbau, Gustav-Kirchhoff-Straße 1
R. K 1009
Intended use:
The surge voltage test system is used to determine the behaviour of electrical systems and their components when subjected to brief overvoltages, such as those that can occur due to atmospheric influences. The knowledge gained is used for the further development of insulating material applications.
Plant description:
The surge voltage test facility consists of DC voltage generation, surge generator according to "Marx" with surge capacitors, charging and discharging resistors as well as spark gaps, voltage divider for measuring the peak value of the voltage and a control panel which contains all necessary operating and monitoring elements. Additional equipment includes a measuring spark gap and a surge voltage triggering device for the timed provision of the surge voltage. Positive and negative impulse voltages can be realized by reversing the polarity of the DC voltage generation.
Technical data:
| Surge voltage form | 1.2 / 50 µs |
| Surge voltage peak value | max. 750 kV |
| Number of stages | 6 |
| Pulse power | 6,6 kWs |
| Surge capacitance | 23.4 nF |
| Surge capacitors per stage | 4 |
| Voltage divider capacitance | 1.125 nF |
Intended Use:
The DC voltage test equipment is used for testing insulation arrangements and for testing devices and equipment, such as testing cables or high-voltage capacitors.
Thus, its place of application can be found in test fields of device and plant manufacturers and in research and development.
Structure of the plant:
The structure of the system consists of a variable transformer for stepless regulation of the voltage with fine adjustment. A high-voltage transformer transforms the mains voltage and feeds it to a Greinacher doubler circuit, which consists of 2 high-performance rectifiers connected against each other and 2 high-voltage capacitors. To limit the current, a protective resistor is switched on towards the pickup. The voltage is measured by means of an ohmic divider, the low-voltage side of which is fed to a peak or r.m.s. meter. The control of the system can be operated manually or automatically with voltage preselection. The control panel contains all necessary operating and monitoring elements. Ball spark gap and digital storage oscilloscope serve as additional equipment for exact determination of the voltage.
Technical data:
| Maximum voltage level | 1.2 / 50 µs |
Polarity of voltage against earth | max. 750 kV |
| Number of stages | 6 |
| Pulse power | 6,6 kWs |
| Surge capacitance | 23.4 nF |
| Surge capacitors per stage | 4 |
| Voltage divider capacitance | 1.125 nF |
Intended use:
The AC voltage test equipment is used for the generation of high-voltage single-pole earthed operating-frequency AC voltages which are continuously adjustable from zero to a maximum value of 250 kV. Its main application is the testing of insulation arrangements as well as devices and plant components. However, breakdown and flashover voltages on insulators and cables can also be determined.
Design of the system:
The system consists essentially of a single-phase high-voltage transformer, a variable transformer for stepless regulation of the voltage, a high-load resistor for damping and limiting the current, a compressed gas capacitor for setting up a voltage divider for voltage measurement, and a control panel with all the necessary operating and monitoring elements. Additional equipment includes a current measuring and voltage measuring device, a spherical spark gap and a partial discharge measuring device. The temporal course of current and voltage can be followed via an oscilloscope.
Technical data:
| Maximum voltage level | 250 kV rms |
| Nominal current at nominal voltage | 200 mA |
| Connected load | 50 kVA |
| Supply voltage | 220 V |
| Transformation ratio of the high voltage transformer | 1:715 |
Intended use:
This small test kit up to 100 kV nominal voltage is primarily intended for engineering education of students, but also for job-related training. Its diversity is so comprehensive that it can be used to implement any type of test circuit. Not only AC and DC test circuits, but also surge voltage and measuring circuits can be realized. Thus, in the medium-voltage range, it can be used in insulating material research and diagnostics of equipment, but also for voltage generation for certain technological processes (for example, the automation of high-voltage tests).
Structure of the system:
The modular system consists of the elements high-voltage test transformer, various rectifiers, capacitors from 100 pF to 160 nF, resistors between 800 ohms and 460 kOhms, a blocking inductance of 40 mH, voltage dividers for DC, AC and surge voltage measurement, a compressed gas capacitor of 102.64 pF as well as insulating and connecting elements, discharging and grounding devices. The modular system is controlled by a control cabinet with PC and power section as well as the safety and monitoring devices required for safe operation.
Technical data:
| Rated voltage | 220 / 0 ... 100 kVrms |
| Rated power | 7.3 kVA |
| Max. Rated currents prim/sec. | 36.4 /0.08 A |
| Control cabinet | |
| Control section | WSM-3 |
| Power unit | H 386 |
| Voltmeter (Ueff) | MU 14 |
| Peak value voltage measurement | |
| Field strength meter | Type 704 |
| Pressed gas capacitor | max. 135 kV SW |
| Capacitive voltage divider 0.1 and 0.6 nF | max. 150 kV SW |
| Rectifier elements | max. 270 kV |