Series Resonance Test Device
LHV-135kVA/108kV Resonant Test System for High Voltage Applications
Product Introduction
The LHV-135kVA/108kV Resonant Test System represents the cutting-edge solution for high-voltage cable and transformer testing, combining advanced DSP technology with series resonance principles to deliver unmatched testing efficiency. Compliant with GB 50150-2016, DL/T 849.6-2016, and DL/T 474.4-2018 standards, this system is engineered for demanding field applications.
Main components of the device
Serial number | Device name | Specification and model | Unit | Quantity |
1 | Variable frequency power supply | LHV-7.5kW | Tower | 1 |
2 | Excitation transformer | LHV-7.5kVA/1.5/3/6kV/0.4kV | Tower | 1 |
3 | High voltage reactor | LHV-33.75kVA/27kV | Section | 4 |
4 | Capacitive voltage divider | LHV-1000pF/110kV | Set | 1 |
Main Functions and Features
The UHV-135kVA/108kV series resonance scheme adopts the method of adjusting the power supply frequency to achieve resonance between the reactor and the test capacitor, thereby obtaining high voltage and large current on the test object. Due to its small required power supply, light weight, and compact size, it has received widespread acclaim and application both domestically and internationally. It represents a new method and trend in high-voltage testing.
The main functions and technical features of our company's frequency conversion resonance device are as follows:
1, Protection Functions: The device is equipped with protection functions such as overvoltage, overcurrent, zero-start, and system detuning (flashover). The overvoltage and overcurrent protection values can be set according to user needs. In case of test object flashover, the flashover protection will activate and record the flashover voltage value for test analysis.
2, Lightweight Design: The entire device is lightweight, making it easy to use on-site.
3, Multiple Operation Modes: The device offers three working modes: fully automatic mode, manual mode, and automatic tuning with manual voltage boosting mode. This allows users to flexibly choose based on on-site conditions, improving test efficiency.
4, Data Storage and Printing: The device can store and remotely print data. The stored data is numbered digitally, making it easy for users to identify and retrieve.
5, Automatic Frequency Sweeping: During automatic frequency sweeping, the starting frequency can be set arbitrarily within a specified range, and the sweeping direction can be chosen as upward or downward. A large LCD screen displays the scanning curve, allowing users to intuitively understand whether the resonance point has been found.
6, DSP Platform Technology: The device uses DSP platform technology, allowing for the addition or reduction of functions and upgrades based on user needs. The human-machine interface is more user-friendly.
7, Reduced Power Supply Capacity: The series resonance power supply generates high voltage and large current through resonance between the reactor and the test object's capacitance. In the entire system, the power supply only needs to provide the active power consumption, so the required power supply capacity is only 1/Q of the test capacity.
8, Reduced Weight and Volume: The series resonance device eliminates the need for bulky high-power voltage regulators and conventional high-power frequency test transformers. Moreover, the resonant excitation power supply only requires 1/Q of the test capacity, significantly reducing the system's weight and volume, typically to 1/10-1/30 of conventional test devices.
9, Improved Output Voltage Waveform: The resonance power supply uses a resonant filter circuit, which improves the waveform distortion of the output voltage, providing a high-quality sinusoidal waveform and effectively preventing harmonic peaks from causing false breakdowns in the test object.
10, Prevention of Large Short-Circuit Currents: In a series resonance state, when the insulation weak point of the test object breaks down, the circuit immediately detunes, and the current rapidly drops to 1/Q of the normal test current. In contrast, when using parallel resonance or a test transformer for withstand voltage testing, the breakdown current immediately increases by tens of times. Compared to this, the short-circuit current and breakdown current differ by hundreds of times. Series resonance effectively identifies insulation weak points without the risk of large short-circuit currents damaging the fault point.
11, No Recovery Overvoltage: When the test object breaks down, the high voltage immediately disappears due to the loss of resonance conditions, and the arc extinguishes instantly. The process of re-establishing the recovery voltage is long, making it easy to disconnect the power supply before reaching the flashover voltage again. This voltage recovery process is an intermittent oscillation of energy accumulation, which is prolonged and does not result in any recovery overvoltage.
Main technical parameters and functions
Rated capacity | 135kVA |
Rated voltage | 27kV;54kV;108kV |
Rated current | 5A;2.5A;1.25A |
Measurement accuracy | System RMS level 1.5 |
Operating frequency | 30-300Hz |
Device output waveform | Sinusoidal wave |
Quality factor | Device Q≥30(f=45Hz) |
Waveform distortion rate | Output voltage waveform distortion ≤1% |
Input power supply | Single-phase 220 or three-phase 380V voltage, frequency 50Hz |
Working hours | Allow continuous 60min under rated load; Overpressure 1.1 times 1 minute |
Temperature rise | Temperature rise ≤65K after continuous operation under rated load for 60 minutes |
Protection function | Overvoltage, overcurrent, zero start, system mismatch (flashover) and other protection functions |
Ambient temperature | -20℃-55℃ |
Relative humidity | ≤90%RH |
Altitude | ≤3000m |
Device capacity verification (device capacity is 135kVA, divided into three reactors, reactor single section is 33.75kVA/27kV/1.25A/100H)
Serial number | Test | Test Frequency | Test Current |
1 | 10kV/300mm2 cable 3km AC voltage withstand test, capacitance ≤1.1265μF, test frequency 30-300Hz, test voltage 22kV, test time 5min. Use four reactors in parallel, L=100/4=25H | f=1/2π√LC=1/(2×3.14×√25×1.1265×10-6)=30Hz | I=2πfCU =2π×30×1.1265×10-6×22×103=4.67A |
2 | A35kV/300mm2 cable 1km AC voltage withstand test, capacitance ≤0.1945μF, test frequency 30-300Hz, test voltage 52kV, test time 60min. Use two reactors in series (mutual inductance coefficient 1.15) two groups in parallel, L=100×2×1.15/2=115H | f=1/2π√LC=1/(2×3.14×√115×0.1945×106)=33.65Hz | I=2πfCU =2π×33.65×0.1945×10-6×52×103=2.14A |
3 | Ac voltage withstand test of 35kV/31500kVA main transformer, capacitance ≤0.02μF, test frequency 45-65Hz, test voltage 68kV, test time 1min. Use four reactors in series (mutual inductance coefficient 1.25), L=100×4×1.25=500H | f=1/2π√LC=1/(2×3.14×√500×0.02×10-6)=50.33Hz | I=2πfCU =2π×50.33×0.02×10-6×68×103=0.43A |
Equipment combination method during testing
Test Object | Reactor Selection (33.75kVA/27kV four sections) | Excitation Transformer Output Selection | Test Voltage (kV) |
10kV/300mm2 Cable 3km | Using four reactors in parallel | 1.5kV | ≤22kV |
10kV switch and other substation equipment | Using three reactors in series | 3kV | ≤42kV |
35kV/300mm2 Cable 1km | Using two reactors in series and two groups in parallel | 3kV | ≤52kV |
35kV/31500kVA main transformer | Using four reactors in series | 6kV | ≤68kV |
35kV switch and other electrical equipment | Using four reactors in series | 6kV | ≤95kV |
System Configuration Parameters
(一) Variable Frequency Power Supply UHV-7.5kW (1 unit)
Rated Output Capacity | 7.5kW |
Operating Power Supply | 220/380±10%V(single/three-phase), industrial frequency |
Output Voltage | 0-400V |
Rated Input Current | 18.75A |
Rated Output Current | 18.75A |
Voltage Resolution | 0.01kV |
Voltage Measurement Accuracy | 1.5% |
Frequency Adjustment Range | 30-300Hz |
Frequency Adjustment Resolution | ≤0.1Hz |
Frequency Stability | 0.1% |
Operating Time | Continuous 60min at Rated Capacity |
Maximum Component Temperature at Continuous 60min Operation at Rated Capacity | ≤65K |
Noise Level | ≤50dB |
Dimensions (L×W×H mm) | 400×280×400 |
Weight | Approximately 10kg |
(二) Excitation Transformer UHV-7.5kVA/1.5/3/6kV/0.4kV (1 unit)
Rated Capacity | 7.5kVA |
Input Voltage | 0-400V |
Output Voltage | 1.5/3/6kV |
Structure | Dry Type |
Dimensions (L×W×H mm) | 450×330×430 |
Weight | Approximately 50kg |
(三) High Voltage Reactor UHV-33.75kVA/27kV (4 knots)
Rated Capacity | 33.75kVA |
Rated Voltage | 27kV |
Rated Current | 1.25A |
Inductance | 100H/unit |
Quality Factor | Q≥30(f=45Hz) |
Structure | Dry Type |
Dimensions (Inner Diameter×Height mm) | 302×435 |
Weight | Approximately 55kg |
(四) Capacitive Voltage Divider UHV-1000pF/110kV (1 set)
Rated Voltage | 110kV |
High Voltage Capacitance | 1000pF |
Dielectric Loss | tgσ≤0.5% |
Voltage Division Ratio | 1500:1 |
Measurement Accuracy | Effective Value 1.5 Grade |
Dimensions (Inner Diameter×Height mm) | 140×1000 |
Weight | Approximately 8kg |
Delivery List
No. | Equipment Name | Model and Specifications | Unit | Quantity |
1 | Variable Frequency Power Supply | LHV-7.5kW | Unit | 1 |
2 | Excitation Transformer | LHV-7.5kVA/1.5/3/6kV/0.4kV | Unit | 1 |
3 | High Voltage Reactor | LHV-33.75kVA/27kV | Section | 4 |
4 | Capacitive Voltage Divider | LHV-1000pF/110kV | Set | 1 |
5 | Internal Connection Cables | Set | 1 | |
6 | Factory Inspection Report | Copy | 1 | |
7 | User Manual | Copy | 1 | |
8 | Product Certificate | Copy | 1 | |
9 | Packing List | Copy | 1 |
Reference Test Standards
DL/T 596-1996 | "Preventive Test Code for Electric Power Equipment" |
GB50150-2016 | "Standard for Handover Testing of Electrical Equipment in Electrical Installation Engineering" |
GB10229-88 | "Reactors" |
GB1094 | "Power Transformers" |
GB1094.1-GB1094.6-96 | "Degrees of Protection Provided by Enclosures" |
GB2900 | "Electrotechnical Terminology" |
GB/T16927.1~2-1997 | "High Voltage Test Techniques" |
DL/T474.4-2006 | "Guide for Insulation Test Implementation on Site - AC Withstand Voltage Test" |
DL/T1015 | "Guide for the Use of Voltage Measurement Systems for On-site DC and AC Withstand Voltage Tests" |
GB/T311.1-1997 | "Insulation Coordination and Insulation of High Voltage Power Transmission and Transformation Equipment" |
GB191-2000 | "Pictorial Markings for Packaging and Storage" |
JB/T9641-1999 | "Test Transformers" |
IEC358(1990) | "Coupling Capacitors and Capacitor Dividers" |
GB4793-1984 | "Safety Requirements for Electronic Measuring Instruments" |
GB/T3859.2-1993 | "Application Guide for Semiconductor Converters" |
GB/T2423.8-1995 | "Basic Environmental Testing Procedures for Electrical and Electronic Products" |
DL/T849.6-2004 | "General Technical Specifications for Special Test Instruments for Power Equipment Part 6: High Voltage Frequency Tuning Test Devices" |
Key Specifications:
135kVA/108kV testing capacity
3km cable testing capability (10kV/300mm²)
DSP-controlled precision measurement platform
30-300Hz adjustable test frequency range
1/Q power efficiency (up to 90% energy saving)
Standard Test Capabilities
Test Object | Parameters | Test Voltage | Duration |
---|---|---|---|
10kV/300mm² Cable (3km) | ≤1.1265μF | 22kV | 5min |
35kV/300mm² Cable (1km) | ≤0.1945μF | 52kV | 60min |
35kV/31500kVA Transformer | ≤0.02μF | 68kV | 1min |
35kV Switchgear | - | ≤95kV | 1min |
Core Technologies
Series Resonance Principle
The system utilizes LC resonance between the reactor and test object's capacitance to:
Generate high voltage with minimal input power (1/Q of test capacity)
Produce pure sinusoidal waveforms (THD <3%)
Automatically limit fault currents to 1/Q values during breakdown
DSP Control Platform
Real-time frequency sweep (30-300Hz range)
Automatic resonance point detection
Digital protection algorithms
Upgradable firmware architecture
Safety Protection System
Overvoltage Protection
110% rated voltage cutoff with 1ms response
Overcurrent Protection
120% current threshold with adjustable settings
Flashover Protection
Automatic arc extinguishing and voltage collapse
Zero-start Interlock
Prevents improper energization sequences
Field Operation Advantages
Feature | LHV-135 System | Conventional Test Sets |
---|---|---|
Power Requirement | 10-30kW | 100-150kW |
Total Weight | ≈800kg | ≈3000kg |
Setup Time | <30 minutes | 2-3 hours |
Waveform Quality | THD <3% | THD 5-8% |
Unique Technical Features
1. Intelligent Frequency Sweep
Bidirectional scanning (up/down frequency)
Customizable start frequency
Visual resonance curve display
2. Flexible Operation Modes
Fully Automatic: One-touch test completion
Semi-Automatic: Manual voltage ramp after auto-tuning
Manual: Expert control mode
3. Data Management
1000+ test records storage
Digital timestamp indexing
Remote printing capability
Safety Benefits
Fault Current Limitation
Breakdown currents limited to <10% of test current
No Voltage Overshoot
Gradual resonance re-establishment prevents transients
Instant Arc Quenching
Automatic de-energization within 1ms of flashover