LZR-Series Neutral Grounding Resistor (NGR)
Low Resistance Grounding System
Low Impedance Grounding Equipment for Detecting Ground Fault Current of a Medium Voltage Generator or Transformer Neutral
SAFE RELIABLE EFFECTIVE GROUNDING
APT’s low impedance grounding Neutral Grounding Resistor and Reactor will reduce the stress and amount of damage to your power system equipment. They do this by controlling the magnitude of the ground fault currents.
- When used in generator neutral, these devices will also limit the amount of the generator available Line to Neutral fault current below the design limits set by the NEMA MG1 generators design standard.
- Additionally, APT Neutral Grounding Resistors and Reactors will reduce the magnitude of the harmonic currents. This circulates in the neutrals of paralleled generators due to the differences in the generator winding pitches, armature reaction, and other system conditions.
APT Neutral Grounding Resistors help switchgear sense that there is current in neutral/ground. The NGR’s help dissipate that current.
Voltage Ratings
2.4kV-15kV
Current Ratings
100A – 400A
Temperature Rise
1400°F (Maximum)
MV Part Number Configurator & Budgetary Pricing
[caldera_form id=”CF5bd8960ce7833″]
Neutral Grounding Resistor Core Features
- Used in the neutrals of generators, transformers, and other rotating machines
- Performs best when operated in a 120°F maximum ambient temperature, 0°F minimum ambient temperature, and an altitude 6000 feet or lower
- Standard Enclosure includes:
- Filtered ventilation louvers
- NEMA 1/3R for indoor/outdoor applications
- Hot Dip Galvanized
- Cables: Bottom Entry/Exit
- Enclosure Options:
- Aluminum, Stainless Steel (304 or 316)
- Powder coated ANSI 61 Gray or custom colors
- One or two connection bushings that can either be top or side mounted
- LZR-P Option to accommodate tight lead time requirements and other site-specific specifications
- Window Type or Bar Type Current Transformer, with secondary terminals available for field interconnection to the ground fault relay
- Unfused or Fused Voltage Transformer
- Maximum Dimensions: 40″W x 38″D x 28″H
- Approximate Weight: 500 lbs.
Neutral Grounding Resistor Product Applications
- Electric Utility & Manufacturing
- Water Treatment Plants
- Low Service Pump Stations
- Healthcare
- Data Centers
- Hotel Resorts
- Many more!
Engineering Bid Specifications
Installation Drawings & Diagrams
WE ARE HERE
TO SERVE YOU
We are committed to providing expert support and tailored power solutions. Contact our team today to find the right answers for your needs.
Our Service & Expertise
Advanced Power Technologies (APT) offers a full range of:
- Intelligent power distribution systems
- Low and medium voltage switchgear
- Walk-in equipment buildings
- And more!
We design and build our products in-house, based on how you would like it to be. APT has many different options to create the best and reliable switchgear for your power system.
APT will provide a comprehensive system commissioning and integration once we install our equipment. We will continue our ongoing support during the lifetime of the installation, including:
- Field service upgrades
- Retrofits
LZR-Series
Neutral Grounding
Resistor (NGR)
2.4kV - 15kV Low Resistance Grounding Systems
Engineered to limit ground fault current, protect critical equipment, and enhance personnel safety in medium voltage electrical systems.
VOLTAGE RATING
2.4kV - 15kV
CONTINUOUS CURRENT
100A - 400A
DUTY CYCLE
10 Seconds (Standard)
STANDARD
IEEE Std 32-1972
ENCLOSURES
NEMA 1, 3R & Custom
ENGINEERED
Custom Configurations
WHY LOW RESISTANCE GROUNDING?
- Limits ground fault current to a safe level
- Allows protective relays to operate correctly
- Protects transformers, generators, and cables
- Reduces arc flash energy and equipment damage
- Improves personnel safety
- Minimizes downtime and repair costs
HOW IT WORKS
The LZR-Series limits the ground fault current by introducing a calculated resistance between the neutral and ground, allowing protective devices to quickly clear the fault and protect equipment.
TECHNICAL SPECIFICATIONS
| Voltage Ratings | 2.4kV - 38kV |
| Interrupting Capacity | 25kA, 31.5kA, 40kA, 50* kA |
| Main Bus Ampacity | 600-4000* A |
| Bus Insulation Options | Standard: Bare Optional: Insulated |
| Operation Modes | Manual, Automatic Open Transition, Automatic Closed Transition, Delayed, Soft Loading, Parallel |
| Transfer/Control Configurations | Utility-to-generator, Utility-to-Utility, Generator-to-Generator, 3-way |
| Circuit Disconnect Types | Withdrawable Vacuum Circuit Breaker, Fixed Mount Vacuum Circuit Breaker, Air Insulated Load Break Switch |
| Reference Standards | ANSI/IEEE: C37.20.3, C37.04, C37.06 |
APPLICATIONS
DOCUMENTATION
Product Brochure
Specifications
Installation Drawings
Need help finding the right solution?
Our team of experts is here to help you select the right switchgear for your application.
Reliable Performance
High-performance vacuum circuit breakers provide fast fault clearing and long service life with minimal maintenance.
Enhanced Safety
Mechanical interlocks and compartmentalized construction prevent unsafe operation and protect operators.
Modular Design
Configurable sections support multiple system architectures including main-tie-main and generator paralleling.
Low Maintenance
Draw-out breaker design with test, disconnected, and connected positions simplifies servicing and reduces downtime.
The MED-Series combines high-quality components with a design focused on durability, accessibility, and long-term performance. Its drawout construction and modular architecture provide flexibility for a wide range of applications and environments.
- Draw-out vacuum circuit breakers with multiple operating positions
- Silver-plated copper bus bar connections
- Front-accessible current transformers
- Fixed or draw-out voltage transformers
- Indoor and outdoor enclosure options
Voltage Ratings
2.4kV – 38kV
Interrupting Capacity
25kA, 31.5kA, 40kA, 50kA
Main Bus Ampacity
600–4000A
Bus Insulation Options
Standard: Bare
Optional: Insulated
Optional: Insulated
Operation Modes
Manual, Automatic Open Transition, Automatic Closed Transition,
Delayed, Soft Loading, Parallel
Delayed, Soft Loading, Parallel
Transfer/Control Configurations
Utility-to-generator, Utility-to-Utility,
Generator-to-Generator, 3-way
Generator-to-Generator, 3-way
Circuit Disconnect Types
Withdrawable Vacuum Circuit Breaker,
Fixed Mount Vacuum Circuit Breaker,
Air Insulated Load Break Switch
Fixed Mount Vacuum Circuit Breaker,
Air Insulated Load Break Switch
Reference Standards
ANSI/IEEE: C37.20.3, C37.04, C37.06
Industrial
Textile, steel mills, stamping
Data Centers
Medium Voltage Switchgear, Low Voltage Switchgear, Automatic Transfer & Distribution
University & Medical Campuses
Hospitals, medical clinics, airports, train stations
Utilities
Power generation and distribution systems
Renewables
Solar, wind, and energy storage systems
Commercial Buildings
Office buildings, retail, mixed-use developments
Infrastructure
Transportation hubs, rail, and municipal systems
Oil & Gas
Refineries, pipelines, and processing facilities
Need help finding the right solution?
Our team of experts is here to help you select the right switchgear for your application.